brazil84's Global Warming Thread

[aptronym]

As requested, this thread is mostly to elucidate brazil84's elusive stance on key questions of global warming.

Things to be discussed:

(1) Is global warming real?
a. Is the Earth heating up at all?
b. Can it be attributed to natural variability?
(2) Is global warming anthropogenic?
a. Are greenhouse gases sufficient to explain observed warming?
b. How much of current warming is anthropogenic?
(3) What are the effects of global warming?

Things not to be discussed:
(1') I believe there is a giant conspiracy between the ACLU, the Illuminati, NAMBLA and scientists to bring about the New World Order using global warming to crush democracy and freedom.
(2') Any solution we implement is going to have to involve China and India.
(3') It's going to cost too much to fix global warming.

Because of brazil84's apparent preference for the U.S. National Academy of Sciences, I'm going to primarily cite from the IPCC Third Assessment Report (2001), the last IPCC report to be reviewed by the NAS Climate Change Report (2001). The IPCC Fourth Assessment Report (2007) has the most current information, but the NAS has yet to say anything about it.

Is global warming real?

Yes. We have an instrumental temperature record that goes back to 1850, which means we have first-hand data (no proxies) for global warming. Satellite data also shows the same level of warming from 1980 to present, despite deniers' claims to the contrary - early reports of the satellite data failed to take into account the cooling of the stratosphere due to ozone depletion; as a result, the altitude-averaged temperatures appeared to remain constant, when the reality was that the stratosphere cooled while the troposphere warmed.

The existence of a Medieval Warm Period (which is included in the texts of the 3AR and 4AR but confusingly missing from the Summaries) really has limited influence on this conclusion - absolute temperature doesn't matter since humans are adaptable; rate of temperature change is the key. Historically, temperatures have moved about 0.3^oC per century in recent history, current warming is 1^oC per century.

Is global warming anthropogenic?

It may be helpful to clear up some easily-confused terms. The greenhouse effect is what keeps us alive - based on Earth's distance from the Sun and the Stefan-Boltzmann blackbody radiation law, Earth should be a frigid -15^oC on average. Yet its average temperature is +20^oC - a 35^oC warming which is due to greenhouse gases - about 95% due to water (H₂O), and 5% due to carbon dioxide (CO₂), with all the rest of the gases contributing some miniscule amount. If the greenhouse effect were to be doubled, water would start spontaneously boiling in the tropics, and if the greenhouse effect were to be eliminated, water would freeze everywhere except for the tropics.

Not surprisingly, increasing the CO₂ (or H₂O, but we don't generate enough) will increase the greenhouse effect. This difference is anthropogenic global warming. Experimentally, we're seeing a 38% increase in CO₂ levels since the Industrial Revolution, which, if the greenhouse effect were linear, would correspond to about a 0.7^oC warming. Just to be clear, the greenhouse effect is certainly not linear, but we're in the right ballpark here.

The IPCC has gone through great lengths to quantify the effects of all greenhouse gases, converting each into a unit called radiative forcing. This essentially means "how much brighter the Sun looks". Positive radiative forcing corresponds to warming; negative to cooling. Of all the things we do, emitting CO₂, CH₄, NO_x's, CFC's, and tropospheric ozone tend to warm the planet. Sending up particulates, sulfates, and stratospheric ozone depletion tend to cool the planet.

The radiative forcing from increases in solar output are also included. The Sun itself is warming the Earth, but about 12x less than the humans' net effect. Anthropogenic effects are currently "pushing" 12x harder than natural effects.

Of course, one could argue this was different in the past, and while we only have greenhouse gas data back to 1950, we have a lot of natural data back much further (or we can use proxies). We can then use computers to determine whether natural data can explain the temperature record we see.

In the case of a warming period from 1880 to 1940, we can. In the case of the current warming period from 1970 to 2000, we can't. Thus, the warming period from 1970 to 2000 is at least partially anthropogenic, and by 2001, we know it's nearly all anthropogenic. The IPCC sums it in 2001 as such: that the current warming is very likely (defined as 90% certainty) at least partially anthropogenic, and likely (defined as 66% certainty) mostly anthropogenic. In 2007, the confidence level was boosted so that it is now very likely mostly anthropogenic.

What are the effects of global warming?

Predicting the future is difficult, and while many deniers like to attack computer modeling, it's important to note that the major uncertainty in the climate models is economics, not climate. The models make assumptions about world economic growth and population growth; while many of the runs vary 2-fold or 4-fold in terms of predicting warming, I would challenge economists to come up with a simple economic model that doesn't have the same variability.

That being said, the IPCC has classified scenarios into four broad categories (with one category subdivided into 3 levels), called SRES. The "A" scenarios assume that countries will make economic, rather than environmental ("B") decisions. The "1" scenarios assume that countries will make united, rather than fragmented ("2") decisions. The A1 (united, economic) scenario is subdivided into three parts, depending on whether countries adopt alternative fuels as soon as available (A1T), keep using fossil fuels (A1F), or some blend (A1B).

It's important to note that every single scenario, even the enviro-fantasy B1, assumes population growth through 2050 and warming through 2100; every scenario besides B1 assumes we'll be emitting more (as a planet) in 2100 than we are now. Warming is inevitable; on the other hand, how bad of a warming is dependent on our actions.

This is an important point - how bad global warming will be is mostly a function of the scenario. The interscenario variability is greater than the intrascenario variability in most cases.

The B1 (united, environmental) scenario is obviously the best case. A 1.1-2.9^oC warming is anticipated (negligible to mild) and sea levels will rise 7-15".

The A1F (united, economic, fossil fuel based) scenarios are the worst, with warming of 2.4-6.4^oC and sea level rises of 10-23".

Concurrent with this warming will be a host of effects, starting with "increased coral bleaching" around +1^oC, progressing to agricultural shifts around +2^oC (decreases in low latitudes and increases in high latitudes), increased coastal flooding around +3.5^oC, and "substantial burden on health services" at +4.5^oC.

This should sound surprisingly mild to you - after all, people have been quoting figures of 20 feet or higher for sea level rises (if they watched Gore's movie but didn't read the fine print) or claiming that there will be some sort of "runaway" greenhouse effect that turns us into Venus (the possibility of which isn't even addressed in the IPCC report). However, this is what science says.

Why am I posting all this?

Well, first of all, to make the point that the global warming debate is (a) partitioned, and (b) sequential. The fact that the Earth is warming has really no bearing on whether it's our fault; that we're at fault doesn't necessarily mean that we need to fix anything (there's a 5% chance that we could burn fossil fuels to our heart's content for 100 years and only see +2.4^oC warming ... on the other hand, there's also a 5% chance that we'd see a disasterous +6.4^oC warming). Each of these questions is separate and independent.

Secondly, because I really think a lot of people end up with really skewed views of global warming. You have a faction which doesn't even know the difference between peer-reviewed journal articles and weblogs claiming "experts" have "debunked" global warming; on the other hand, there's a faction which thinks that the world is going to end in 20 years if we don't do something immediate and drastic. The evidence in favor of anthropogenic global warming is public (and free on the web, as linked above), it's readable for non-scientists (see the Summaries for Policymakers), and most of all, it's clear that the Earth is warming and that we're a major, if not the major, cause.

Economic analysis will play a greater role from now on, but the analysis can't rely on glib assumptions about how money can fix everything. You want a good analysis? Simply go through the effects of global warming from the IPCC report(s), quantify them so that we have a function of cost per degree warming, and then come up with a weighted average of the cost per SRES scenario. Then the question of whether it's cost-effective to fix something becomes trivial - if we need to bribe China with $100 billion in clean technology but save 0.5^oC warming (which works out to $150 billion in costs), then let's go for it. On the other hand, if a Kyoto extension going to cost us $200 billion and save the same amount of warming, it'd be better to deal with later.

[Quartz]

An excellent post.

Originally Posted by aptronym

Experimentally, we're seeing a 38% increase in CO2 levels since the Industrial Revolution, which, if the greenhouse effect were linear, would correspond to about a 0.7oC warming

Can you give a non-model cite for how that figure was calculated?

And I'm significantly skeptical of the IPCC. See here.

At a recent CIRES meeting, Gerald North stated that “cherry picking” is a legitimate method in palaeoclimatology. He said because one is looking for a certain, elusive “signal” from the noise, that’s the only way to find the data.

Sorry. Cherry picking is not valid at all.

Dr Mann was obliged to issue a corrigendum (PDF 44KB) in July 2004 acknowledging at least that his key IPCC study was documented in a careless way and was effectively unverifiable.

The Wegman Report (PDF 1.41MB) demonstrated that the various historic reconstructions alleged to corroborate the “hockey stick” were not as independent as claimed, sharing both authors and data.

Here's what I see as a major flaw in your post:

Originally Posted by aptronym

Predicting the future is difficult, and while many deniers like to attack computer modeling, it's important to note that the major uncertainty in the climate models is economics, not climate. The models make assumptions about world economic growth and population growth; while many of the runs vary 2-fold or 4-fold in terms of predicting warming, I would challenge economists to come up with a simple economic model that doesn't have the same variability.

That's irrelevant. Models can't be trusted and that's that. Remember how the Met Office said that 2007 would be one of the warmest?

Originally Posted by Met Office

Katie Hopkins from Met Office Consulting said: "This new information represents another warning that climate change is happening around the world. Our work in the climate change consultancy team applies Met Office research to help businesses mitigate against risk and adapt at a strategic level for success in the new environment."

2007 was actually very different. A wet and cold summer with floods here, a low hurricane season in America, record cold winters in South America, expansion of Antarctic ice...

Someone with access to the International Journal of Climatology of the Royal Meteorlogical Society might care to fact-check this link.

Has the Earth warmed? Absolutely. Has humanity anything to do with it? I don't know.

[brazil84]

Originally Posted by aptronym

The existence of a Medieval Warm Period (which is included in the texts of the 3AR and 4AR but confusingly missing from the Summaries) really has limited influence on this conclusion - absolute temperature doesn't matter since humans are adaptable; rate of temperature change is the key. Historically, temperatures have moved about 0.3^oC per century in recent history, current warming is 1^oC per century.

For reasons explained in my "temperature record" thread, I dispute this.

In the case of a warming period from 1880 to 1940, we can. In the case of the current warming period from 1970 to 2000, we can't.

Let's make sure we're clear here: Your argument is that scientists can't think of any explanation (besides CO2) that could account for the warming observed between 1970 and 2000 and therefore CO2 must be the cause. Right?

Predicting the future is difficult, and while many deniers like to attack computer modeling, it's important to note that the major uncertainty in the climate models is economics, not climate.

Do you have a cite for that?

I would challenge economists to come up with a simple economic model that doesn't have the same variability.

Probably they can't. As the saying goes, economists predicted 7 out of the last 3 recessions.

[aptronym]

Originally Posted by Quartz

Can you give a non-model cite for how that figure was calculated?

I'm not entirely sure which figure you're referring to, the 38% CO₂ rise or the 0.7^oC effect.

The latter is easier to settle: the difference between the calculated blackbody temperature of the Earth and the actual blackbody temperature of the Earth, multiplied by the increase in carbon dioxide times the global warming potential of carbon dioxide divided by the total concentrations of all greenhouse gases weighted by their global warming potentials.

The former is disputed by some scientists - they believe pre-Industrial levels are estimated to be too low. Without addressing the validity of their arguments or counterarguments, I'll point out that the direct instrumental record shows an increase from 310 ppm to 380 ppm, so it's undisputed there's been at least a 23% increase. If you believe the disputers, it's only 23%. If you believe the IPCC, it's 38% (280 ppm to 380 ppm). Either way, the main point is that the objection "CO₂ is a minor gas and cannot affect global climate" is false. The order of magnitude of the observed effect is correct.

Originally Posted by Quartz

I'm significantly skeptical of the IPCC.

I don't object. As a matter of fact, I'll give you an even better reason to be suspect of the IPCC - the members are picked by politicians. It's no surprise that their assessment will match certain political agendas.

However, being biased does not necessarily mean they're wrong. And the strongest case for accepting the IPCC Third Assessment Report is that the US National Academy of Sciences supported it.

Let's say you created a panel of top U.S. scientists, and charged them with investigating scientific matters and making policy recommendations to Congress. This panel would propagate itself by invitation of existing members. Now, you let them do their own thing for 100 years, and then ask them about global warming. They come back with an assessment which is contrary to the policies of the funding agency, and the funding agency ignores the assessment. Would you say that this panel is free of any charge of bias?

If so, then please accept the National Academy of Sciences report. They disagree with some of the details, but the basic message is clear: the IPCC (3AR) has it right, the Earth is warming and humans are a cause if not the cause.

Originally Posted by Quartz

Here's what I see as a major flaw in your post ... Models can't be trusted and that's that.

This is a philosophical argument - the claims are neither verifiable nor falsifiable. I think most people think models can be trusted. In the context of this thread specifically, brazil84 has much-touted trust in 100-year predictions of GDP, so he certainly trusts models.

I suppose if you don't trust models at all, then I agree - you have no reason to believe that the Earth will warm over the next 100 years any more than you have reason to believe that your 401k will grow at a long-term average of 7% per year. However, I suspect that you do trust the latter - and I would request you explain the difference.

Originally Posted by Quartz

Remember how the Met Office said that 2007 would be one of the warmest?

I don't know who or what the Met Office is, or why they would have any authority in picking which year is the warmest.

In any case, however, those sorts of predictions are irrelevant. Climate requires long-term averages. Solar cycles move in 11-year periods (which definitely affect temperature), so at the very least, any prediction which does not involve an 11-year average is useless. It's like predicting that the stock market will hit a new high in 2008. Based on history and computer modeling, this is a decent, but far-from-sure bet. However, if you were to bet that the stock market average from 2008-2018 will be higher than the average from 1998-2008, that would be an excellent bet.

Originally Posted by Quartz

Someone with access to the International Journal of Climatology of the Royal Meteorlogical Society might care to fact-check this link.

I don't have access to IJC, but I'll take the opportunity to point out the value of fact-checking. This is something that scientists have to do before publication - the process is called peer review.

Science magazine did a survey of climate change articles in 2003, checking the ISI database (not comprehensive, but pretty close and definitely includes all the most prestigious journals) to see which peer-reviewed articles agreed or disagreed with the 2001 IPCC "consensus". Of 928 articles found, 75% explicitly or implicitly agreed with the IPCC; 25% had no or neutral opinion, and 0 articles disagreed. Now, I know personally that there were at least two articles that did disagree in that time period, but they were probably just in journals too minor be covered by the ISI.

So, let's say that this article from the International Journal of Climatology checks out - that it vehemently disagrees with the IPCC. Is there a reason why we should trust these three opposition articles rather than the 650 articles in favor of the consensus?

Originally Posted by brazil84

For reasons explained in my "temperature record" thread, I dispute this.

Can you repost it here, or give me a post number so I could look it up?

Originally Posted by brazil84

Let's make sure we're clear here: Your argument is that scientists can't think of any explanation (besides CO2) that could account for the warming observed between 1970 and 2000 and therefore CO2 must be the cause. Right?

Half of the second half of my argument, yes. The first half revolves around radiative forcing - we know from first principles that CO₂ should warm the atmosphere and we know the Earth is warming. The second half revolves around the question of attribution - the estimated size of the effect (from first principles) matches the size of the observed effect, and if we combine natural and anthropogenic effects in computer models, we can reconstruct the last 100 years of temperature pretty well.

Originally Posted by brazil84

Do you have a cite for that [uncertainty in climate models is economic]?

I thought I had demonstrated this in the text. Each of the SRES scenarios has small variability within a set of economic assumptions; the variability between different sets of economic assumptions is much greater.

[Lamar Mundane]

Originally Posted by Quartz

That's irrelevant. Models can't be trusted and that's that. Remember how the Met Office said that 2007 would be one of the warmest?



2007 was actually very different. A wet and cold summer with floods here, a low hurricane season in America, record cold winters in South America, expansion of Antarctic ice...

Originally Posted by Goddard Institute for Space Studies

Through the first 11 months, 2007 is the second warmest year in the period of
instrumental data, behind the record warmth of 2005, in the Goddard Institute for Space Studies
(GISS) analysis. The unusual warmth in 2007 is noteworthy because it occurs at a time when
solar irradiance is at a minimum and the equatorial Pacific Ocean has entered the cool phase of
its natural El Nino – La Nina cycle.

http://www.columbia.edu/~jeh1/mailin...10_GISTEMP.pdf (.pdf)

[jshore]

Originally Posted by Quartz

An excellent post.

Since aptronym has given a nice response to your post, I will just comment on things that I have something additional to say on.

And I'm significantly skeptical of the IPCC. See here.

Perhaps you ought to also reserve some skepticism for your own link. It is to an opinion piece by someone whose qualifications (according to the blurb at the bottom) are that he was trained as an engineer and worked in the computer industry. He claims to have followed the debate on climate change and notes that he has published in two journals although one is apparently an economics journal while the other is an interdisciplinary journal with a rather pathetic reputation.

Sorry. Cherry picking is not valid at all.

And, this is even worse. The claim in that piece that North in fact said this is (if you follow the link) a comment made by someone, god knows who he/she actually is, on the ClimateAudit website. No exact quote is in fact given. We have no idea if he got the gist of what North said at all accurate but I kind of doubt it. My best guess is that North said something to the effect that one often does have to come up with criteria to choose which proxies to use...but presumably there should be a legitimate criterion such as how well they correlate with temperature for the overlap period with the instrumental temperature record (that was the criterion that I know Osburn and Briffa used in their Science article a few years back).

Remember how the Met Office said that 2007 would be one of the warmest?

As aptronym noted, this prediction is a very different sort of prediction than the kind of long term prediction of how the climate will respond on average to a known forcing. It is a prediction of a fluctuation. This is probably why the Met Office only gave a 60% chance that 2007 would be the warmest year. Indeed, the El Nino died off rather quicker than expected and turned into a La Nina by the second half of the year.

2007 was actually very different. A wet and cold summer with floods here, a low hurricane season in America, record cold winters in South America, expansion of Antarctic ice...

Actually, you are wrong. 2007 was, overall, quite a warm year on a global scale. In fact, it looks like it will be about tied for the 6th warmest on record. [Note added in preview: or, as Lamar Mundane has noted, 2nd or 3rd warmest if you use the NASA GISS results. The preliminary 6th ranking is based on the British/Australian HADCRUT data.]

They predicted in your link that the global temperature would be about 0.54 C above the 1961-1990 average and it looks to come out more like 0.43 C above that average, which is in fact within the 95% confidence range of 0.38 to 0.70 C given by the Met office.

And, since you gave (without any cites) a few local facts that you had cherrypicked, I'll throw in a few more: Arctic sea ice extent reached a record low this summer and January 2007 was the warmest January on record globally, the December 2006 -- February 2007 period was also globally the warmest winter on record.

Someone with access to the International Journal of Climatology of the Royal Meteorlogical Society might care to fact-check this link.

I don't have access. As aptronym notes, there are thousands of articles published on climate science so it is always possible to cherrypick (cherrypicking bad?) a few that support the skeptical view. This is a very new one that scientists have not had much of chance to respond to yet but here is a review of it from RealClimate which seems to show that it has real problems. Among other things, they misuse the concept of standard deviation and standard error in order to show unreasonably small error bars for the spread in the models, thus making it look like the data falls well outside the model spread when it doesn't.

Has the Earth warmed? Absolutely. Has humanity anything to do with it? I don't know.

Well you may not know. But the scientific community has concluded, with high confidence, that we are responsible for most of the warming in the last 50 years.

[brazil84]

Originally Posted by aptronym

Can you repost it here, or give me a post number so I could look it up?

I could, but I'd rather discuss it in the other thread.

the estimated size of the effect (from first principles) matches the size of the observed effect,

Do you have a cite for that?

I thought I had demonstrated this in the text. Each of the SRES scenarios has small variability within a set of economic assumptions; the variability between different sets of economic assumptions is much greater.

I disagree. Even accepting the IPCC scenarios, we could combine and ridivide the scenarios between "sensitive" and "non-sensitive," i.e. response of the climate to CO2.

Using your numbers, and assuming a "nonsensitive" scenario, the total anticipated warming is between 1.1 and 2.4 degrees C. Assuming a "sensitive" scenario, the total warming is between 2.9 and 6.4 C. So it would appear that uncertainty in sensitivity is at least as important as uncertainty in politics/economics.

And sensitivity would become even more important compared to economics/politics if you take out the politics.

This is all using your IPCC numbers of course. Ironically, I happen to believe that economic change will end up being far more important in the end than hypothetical climate change.

[brazil84]

Originally Posted by jshore

Perhaps you ought to also reserve some skepticism for your own link. It is to an opinion piece by someone whose qualifications (according to the blurb at the bottom) are that he was trained as an engineer and worked in the computer industry. He claims to have followed the debate on climate change and notes that he has published in two journals although one is apparently an economics journal while the other is an interdisciplinary journal with a rather pathetic reputation.

But what about the merits of the arguments he presented? Aren't those worth discussing? And would it suprise you to learn that your cherished NAS has cited to E & E?

As aptronym noted, this prediction is a very different sort of prediction than the kind of long term prediction of how the climate will respond on average to a known forcing.

Another difference is that one can be easily checked. Reminds of an afternoon I spent looking through the newspaper many years ago. There was an add for a "gifted psychic" who would answer one free question over the phone. Just for kicks, I called. My first question: Which horse will win at the track this week? Her answer: Sorry, but I can't reveal that kind of information. My next question: When will war end in Country X? Her answer? "20 years."

Now, why do you suppose gifted psychics prefer to make predictions 20 years in advance rather than 1 week in advance?

[elucidator]

Yeah, its not easy being Green. But its not that damned difficult, either.

Why dont we have clean, green energy? Because its impossible? Maybe, but we don't know that. Personally, I doubt it, given human ingenuity. We don't have geen energy because there was never any money in it.

Lets pretend you got the big flash, the Eureka! moment, suddenly....just to pick one....you knew exactly how to render wind energy 100 times more energy productive. Now say you had this idea forty years ago, how would you guess your odds of getting a research grant to pursue this wild ass crackpot scheme? Why don't you do something sensible, like research that may increase the octane of gasoline by 2%? Why don't you go find another use for corn? (I sometimes think that the USDA is nothing more than a diabolical conspiracy by the corn plant for world domination. But I digress...)

Had that idea thirty years ago, maybe you could get funded by that rarest of beings, the dirty fucking hippy with money. Twenty, better odds. Ten years, better still, but now... Now you have a shot at it!

Sometimes the ideas we need are crackpot, sometimes they are not, but you won't find out without trying. Remember Arthur Clarke: "If an old and distinguished scientist tellls you something is possible, he's very probably right. If an old and distinguished scientist tells you something is impossible, he is almost certainly wrong."

John McCain made a good if obvious point today: suppose you're wrong, and we ignore it, and the predicted catastrophe's come about. OK, thats one side. Now suppose we're wrong, but we go ahead and upgrade our energy system to clean and green. What have we lost but leaving a better world for our grandchildren and theirs?

And to top it off, as a flag-waving, patriotic radical American, I want us to do it. We could do with another moon landing, the Super Bowls are getting a mite stale. I want it to be us because we are the best equipped, because we can, because we should, and because we can sell the result. It'll beggar the Saudis, of course. Can't win them all.

If not us, who? If not now, when?

[aptronym]

Originally Posted by brazil84

I could, but I'd rather discuss it in the other thread.

Sure, but I'm not thrilled about combing through 138 posts to find the one point that you've already alluded to. Beginning, middle, end?

Originally Posted by brazil84

Do you have a cite for that?

There's no citation needed for first-principle calculations, but I'll give you links to all the relevant principles.

Stefan-Boltzmann Law: Relates blackbody temperature of an object to the energy flux.
Solar characteristics, specifically, the radius of the Sun and the blackbody temperature of the surface.
Terran characteristics, specifically, the radius of the Earth, the distance to the Sun, and the albedo of the Earth.

Derivation:
(Edit: sorry, the HTML codes for Greek letters doesn't work.)
E_in = E_out
φ_Sun*f_Sun->Earth*f_absorbed = φ_Earth
σT⁴_Sun*4πr²_Sun*(πr²_Earth/4πD²_Earth)*(1-A_Earth = σT⁴_Earth*4πr²_Earth
T_Earth = T_Sun*(r_Sun/2D_Earth)^1/2*(1-A_Earth)^1/4 = 5,778*(6.955x10⁸/2/1.496x10¹¹)^1/2*(1-0.367)^1/4 = 248 K (-25^oC).

Actual temperature of the Earth: 287 K (+14^oC, +39 K from predicted)

Originally Posted by brazil84

I disagree. Even accepting the IPCC scenarios ...

You have given zero reason why the IPCC scenarios should not be trusted. As a matter of fact, between this and the economic hockey stick thread, I believe I have given the only real reason to distrust the IPCC, and I've also countered with an adequate explanation of why that reason fails. The NAS accepts the IPCC scenarios.

Originally Posted by brazil84

we could combine and ridivide the scenarios between "sensitive" and "non-sensitive," i.e. response of the climate to CO2.

On what basis are you classifying things as sensitive and non-sensitive?

Originally Posted by brazil84

Using your numbers, and assuming a "nonsensitive" scenario, the total anticipated warming is between 1.1 and 2.4 degrees C. Assuming a "sensitive" scenario, the total warming is between 2.9 and 6.4 C. So it would appear that uncertainty in sensitivity is at least as important as uncertainty in politics/economics.

It appears as if you've just used the uncertainty to classify sensitive vs. non-sensitive, and then used sensitive vs. non-sensitive to point out the uncertainty. If so, this constitutes a circular argument.

Originally Posted by brazil84

Ironically, I happen to believe that economic change will end up being far more important in the end than hypothetical climate change.

Without agreeing or disagreeing with your statement, I'm pointing out that you haven't posted enough data to support this sort of claim.

I'm also calling you to explicitly clarify your stance on my OP, since you're jumping from "we don't even know the Earth is warming" to "we can't do anything about it anyway so why bother" again, and this time, you don't have the excuse of telling me to create a new thread.

(1) Do you accept, without my invoking any sort of "hockey stick" or even any temperature proxies, that global temperatures have risen since the Industrial Revolution (IPCC 3AR, NAS CCR, IPCC 4AR)?

(2) Do you accept that humans are the primary cause of increases in greenhouse gases (IPCC 3AR, NAS CCR, IPCC 4AR)?

(3) Do you accept that increases in greenhouse gases are both competent (i.e. they can explain) and necessary (i.e. they must be invoked) to explaining the observed global temperature record (IPCC 3AR, NAS CCR, IPCC 4AR)?

(4) Do you accept that increasing temperatures will cause net harm (IPCC 4AR)?

I've stated before that I believe these questions need to be answered in order, and that any discussion of mitigation rests on agreement on the first points.

[jshore]

Originally Posted by brazil84

But what about the merits of the arguments he presented? Aren't those worth discussing?

The arguments are the same recycled garbage we've seen a hundred times before.

And would it suprise you to learn that your cherished NAS has cited to E & E?

Well, when they do a review then they may cite a paper from there. (If they didn't, a certain segment of people would of course be in an uproar.) And, I can't say no good paper has ever been published there. However, if you are writing a paper and want to have an impact (and want to make your resume look good), it is better to publish it in a journal that is well-regarded and widely-available rather than one that is only found in a handful of libraries around the world...So, chances are the majority of the papers published there are going to be pretty poor just like the vast majority of students at a college with very low admissions standards aren't going to be top students.

Another difference is that one can be easily checked. Reminds of an afternoon I spent looking through the newspaper many years ago. There was an add for a "gifted psychic" who would answer one free question over the phone. Just for kicks, I called. My first question: Which horse will win at the track this week? Her answer: Sorry, but I can't reveal that kind of information. My next question: When will war end in Country X? Her answer? "20 years."

Now, why do you suppose gifted psychics prefer to make predictions 20 years in advance rather than 1 week in advance?

First of all, you are forgetting the fact I noted that their prediction was not incorrect in the sense that the global temperature for 2007 has fallen fairly easily within their 95% confidence interval.

Second of all, the fact is that in a "noisy" system that has lots of variations at shorter timescales in addition to a longterm trend, it does take a while to see the long-term trend. This is a fact of life. However, the trends have been seen. And, they had been predicted (e.g., by James Hansen) about 20 years ago now.

[jshore]

By the way, I just finished watching a webcast of a talk by Lonnie Thompson from the American Geophysical Union (AGU) meeting in San Francisco. I am not sure if it will be available at all now that the live talk is over but it is definitely worth watching.

One of the things he does is drill ice cores in tropical glacials. On the basis of his results, he says that he believes it is now warmer than it has been any time in the last 2000 years...and in some places in the last 5000 years.

[aptronym]

Originally Posted by jshore

On the basis of his results, he says that he believes it is now warmer than it has been any time in the last 2000 years...and in some places in the last 5000 years.

I think that these sorts of statistics are irrelevant. Absolute temperature really doesn't matter; it's not like the Earth has a perfect temperature and we're drifting from it. The rate at which global temperature is changing is the most important statistic, because if the Earth changes faster than modern civilization can adapt, we'll suffer - economically, at least if not physically.

Let's be realistic - even if the Earth were to warm by 10^oC, the human race would survive, with Nunavut and Siberia as the world's new emerging superpowers. The U.S. and most of Southeast Asia would become barren wastelands as people emigrated over the decades, and the Sahara might merge with the Kalahari to form a superdesert, but from a global perspective, that's not a catastrophe.

If that scenario happened over 1,000 years, I couldn't care less. However, if it happened over 100 years, I'd be pretty worried for my grandchildren, because they'd actually be forced to make immediate, drastic changes.

[jshore]

aptronym: I for the most part agree with you (although, I don't think I would state it as extremely). However, this is relevant to the issue of whether the current temperatures are anomalous, which constitutes one piece of evidence (albeit a very circumstantial one and one that I don't think is the strongest piece but still seems to get a lot of play in people's mind) in regards to what the cause of the current warming is.

At any rate, the timescale of the change certainly matters a lot...although I think a large enough change, even over a period of a thousand years, might cause changes in the ecosystem that are quite definitely bad to humans and even more so to other species (particularly when these plants and animals are already stressed by pollution and habitat loss and fragmentation).

[brazil84]

Originally Posted by aptronym

Sure, but I'm not thrilled about combing through 138 posts to find the one point that you've already alluded to. Beginning, middle, end?

Ask me in that thread and I will answer.

There's no citation needed for first-principle calculations, but I'll give you links to all the relevant principles.

I'm skeptical. Anyway, if one could calculate the effects of increased CO2 from first principles; and the effects were increased temperature that lined up with historical temperatures, then why would anyone use GCMs to predict AGW?

You have given zero reason why the IPCC scenarios should not be trusted.

I'd rather not get sidetracked debating the trustworthiness of the IPCC or any of these other arguments from authority / ad hominem arguments. I'm a lot more interested debating the substantive issues rather than "Your guy accepted grant money from an OIL COMPANY!!" Can we discuss it in another thread?

On what basis are you classifying things as sensitive and non-sensitive?

I took the upper and lower limits of the temperature ranges in your post. The upper limit is the "sensitive" scenario and the lower limit is the "non-sensitive" scenario. I don't see how this is circular.

Without agreeing or disagreeing with your statement, I'm pointing out that you haven't posted enough data to support this sort of claim.

Not as of yet. I happen to believe there's a good chance that a technological singularity is coming. But that's a debate for another thread.

I'm also calling you to explicitly clarify your stance on my OP, since you're jumping from "we don't even know the Earth is warming" to "we can't do anything about it anyway so why bother" again, and this time, you don't have the excuse of telling me to create a new thread.

Where did I say these things?

(1) Do you accept, without my invoking any sort of "hockey stick" or even any temperature proxies, that global temperatures have risen since the Industrial Revolution (IPCC 3AR, NAS CCR, IPCC 4AR)?

I think that's probably true but I think it's likely that global temperatures haven't risen as much as some claim.

(2) Do you accept that humans are the primary cause of increases in greenhouse gases (IPCC 3AR, NAS CCR, IPCC 4AR)?

I don't know.

(3) Do you accept that increases in greenhouse gases are both competent (i.e. they can explain) and necessary (i.e. they must be invoked) to explaining the observed global temperature record (IPCC 3AR, NAS CCR, IPCC 4AR)?

No.

(4) Do you accept that increasing temperatures will cause net harm (IPCC 4AR)?

No.

I've stated before that I believe these questions need to be answered in order, and that any discussion of mitigation rests on agreement on the first points.

I disagree with this. For example, if we were 100% certain that it was impossible to stop CO2 levels from increasing, the other questions would be essentially academic.

[Quartz]

Originally Posted by aptronym

I'm not entirely sure which figure you're referring to, the 38% CO₂ rise or the 0.7^oC effect.

The latter is easier to settle:

And what I was after. Thank you.

Would you say that this panel is free of any charge of bias?

I agree that it's an excellent sign.

the Earth is warming and humans are a cause if not the cause.

This is actually a significant deviation.

This is a philosophical argument - the claims are neither verifiable nor falsifiable. I think most people think models can be trusted.

Here I think most people simply aren't aware. I have a modest awareness of modelling and as a result know how wrong they can be.

I suppose if you don't trust models at all, then I agree - you have no reason to believe that the Earth will warm over the next 100 years any more than you have reason to believe that your 401k will grow at a long-term average of 7% per year. However, I suspect that you do trust the latter - and I would request you explain the difference.

You'd be doubly mistaken: I'm no American, so don't have a 401k; and I'm well aware that past performance is no indication of future growth. As for the warming, I'll note that the Earth has been warming since the Little Ice Age. How much (if any) is due to man? How much (if any) is due to nature? If it's all - or mostly - due to man, then CO2 emissions are therefore a good thing, else we'd be in another ice age. If it's all or mosly due to nature, then what is the natural cause? And to what degree?

I don't know who or what the Met Office is, or why they would have any authority in picking which year is the warmest.

They're the UK government's weather service.

So, let's say that this article from the International Journal of Climatology checks out - that it vehemently disagrees with the IPCC. Is there a reason why we should trust these three opposition articles rather than the 650 articles in favor of the consensus?

No, but we shouldn't dismiss them either, simply because they dissent.

[brazil84]

Originally Posted by jshore

The arguments are the same recycled garbage we've seen a hundred times before.

I'm not sure I would call it "recycled garbage." For example, the author points the divergence problem. This is a serious problem for temperature reconstructions as discussed in my temperature record thread.

Well, when they do a review then they may cite a paper from there. (If they didn't, a certain segment of people would of course be in an uproar.)

Lol. So when the NAS cites the IPCC, it's because they fully accept what the IPCC says. If the NAS cites an article from E & E, it's because they are bowing to political pressure. Whatever.

By the way, here's the selection from the NAS report:

McIntyre and McKitrick (2003) demonstrated that under some conditions the leading principal component can exhibit a spurious trendlike appearance, which could then lead to a spurious trend in the proxy-based reconstruction.

So, chances are the majority of the papers published there are going to be pretty poor just like the vast majority of students at a college with very low admissions standards aren't going to be top students.

Perhaps, but what matters most is the substance of a person's arguments. Would it surprise you to learn that James Hansen got his degree from the University of Iowa and Richard Lindzen got his degree from Harvard?

First of all, you are forgetting the fact I noted that their prediction was not incorrect in the sense that the global temperature for 2007 has fallen fairly easily within their 95% confidence interval.

Second of all, the fact is that in a "noisy" system that has lots of variations at shorter timescales in addition to a longterm trend, it does take a while to see the long-term trend. This is a fact of life. However, the trends have been seen. And, they had been predicted (e.g., by James Hansen) about 20 years ago now.

Perhaps, but it's interesting that "gifted psychics" tend to put some uncertainty in their predictions as well as to claim that they can't make clear predictions that can be easily verified on a short time frame.

Anyway, if temperatures had steadily risen from 1998 to 2007, people would be screaming that it's convincing evidence of AGW. So, given that temperatures have not followed this path, why isn't it evidence against AGW?

As far as Hansen's predictions go, you might want to check out this link:

http://www.climateaudit.org/?p=796

Looks to me like global temperatures are diverging from his predictions.

[tomndebb]

Ein = Eout
φSun*fSun->Earth*fabsorbed = φEarth
σT4Sun*4πr2Sun*(πr2Earth/4πD2Earth)*(1-AEarth = σT4Earth*4πr2Earth
TEarth = TSun*(rSun/2DEarth)1/2*(1-AEarth)1/4 = 5,778*(6.955x108/2/1.496x1011)1/2*(1-0.367)1/4 = 248 K (-25oC).

By employing the [ symbol ] font tags, the preceding my be rendered as

Ein = Eout
f;Sun*fSun->Earth*fabsorbed = f;Earth
S;T4Sun*4p;r2Sunp;r2Earth/4p;D2Earth)*(1-AEarth = S;T4Earth*4p;r2Earth
TEarth = TSun*(rSun/2DEarth)1/2*(1-AEarth)1/4 = 5,778*(6.955x108/2/1.496x1011)1/2*(1-0.367)1/4 = 248 K (-25oC).

Where phi is f, Sigma is S, and pi is p.

[elucidator]

You guys are just doing that to make us mathtards feel stupid, aren't you?

[Lamar Mundane]

Originally Posted by elucidator

You guys are just doing that to make us mathtards feel stupid, aren't you?

In really general layman's terms (from a lapsed meteorologist): Take what the temperature of the earth would be if it perfectly absorbed all incoming solar radiation, then adjust for the size of the earth and its distance from the sun, then adjust for the natural reflectivity of the earth (atmosphere, clouds, water, snow, etc) then you come up with an expected temperature for the earth. Compare that to the actual temperature of the earth and you get a quantifiable measure of the greenhouse effect (how much the earth's atmosphere is responsible for retaining radiation that would normally get sent back into space.)

Expected temp of the earth = -25C
Actual temp of the earth = +14C

[dropzone]

Originally Posted by elucidator

You guys are just doing that to make us mathtards feel stupid, aren't you?

It's one of them conspiracies.

An anecdote about cherry-picking: My wife and I were watching a show about Millikan's experiment that measured the charge of the electron. The program showed his notebooks, which showed numerous samples he had crossed out. I asked, "How did he get a Nobel when he threw out the results he didn't like?"

"He got the Nobel because he knew which results should be thrown out."

One difference between an expert and and an amateur is the ability to recognize garbage.

[Quartz]

Just to counter my own cite above, and thus illustrate why I'm on the fence, another study says 2007 has indeed been warmer.

[aptronym]

Originally Posted by brazil84

Ask me in that thread and I will answer.

Sounds really evasive, but okay.

Originally Posted by brazil84

I'm skeptical.

Skepticism is fine - the basis of science is skepticism. Skepticism, however, implies that should evidence be presented, you could be convinced. Later in your reply you specifically dismiss all the evidence without any reason - that isn't skepticism, that's ignorance.

Originally Posted by brazil84

if one could calculate the effects of increased CO2 from first principles; and the effects were increased temperature that lined up with historical temperatures, then why would anyone use GCMs to predict AGW?

Because of skepticism. One proof of anthropogenic global warming isn't enough.

Originally Posted by brazil84

I'd rather not get sidetracked debating the trustworthiness of the IPCC or any of these other arguments from authority / ad hominem arguments. I'm a lot more interested debating the substantive issues ...

Yet, you are not debating the substantiative issues and dismissing the IPCC data on an unknown basis.

Your actions are increasingly divergent from your stated intentions.

Originally Posted by brazil84

I took the upper and lower limits of the temperature ranges in your post. The upper limit is the "sensitive" scenario and the lower limit is the "non-sensitive" scenario. I don't see how this is circular.

I misunderstood you because sensitivity is a specifically defined term in climatology - a 1.1-2.9^oC range is insensitive because the variability between runs (1.3^oC) is small and a 2.4-6.4^oC range is sensitive because the variability between runs (4.0^oC) is large.

Your definition makes no sense. I have a sneaking suspicion that you really have no clue what an SRES scenario is, so I'm going to start from ground zero. Out of the thousands of simulations run, each has a different set of economic parameters - population growth, GDP growth, rate of inventing clean technology, etc. Out of all of these, the IPCC grouped the ones that were closest in economic assumption and gave them the 6 SRES categories with the same economic parameters (although each of the individual runs within a group has different climatological parameters). The sensitivity (by the proper definition) of each SRES scenario indicates how dependent the climatological result is on the minor differences in climatological parameters in the same SRES. This gives generally small results: +/- 0.5-1.0^oC. The difference between SRES scenarios, however, is much larger: +/- 1.0-3.0^oC. This indicates that climate models are much more sensitive to differences in economic parameters between different SRES.

Originally Posted by brazil84

I happen to believe there's a good chance that a technological singularity is coming.

Technological singularity or not, it's impossible to compare two values unless you actually know both values. You have shown a profound lack of knowledge about what the climatological score is.

Originally Posted by brazil84

I think that's [that global temperatures have risen] probably true but I think it's likely that global temperatures haven't risen as much as some claim.

On what basis do you contest the instrumental temperature record?

And since I am now openly doubting whether you've even seen the evidence before dismissing it, I am citing exactly which figures and chapters to read so that you have no more excuses.

IPCC 3AR WG1: Chpater 2.2, esp. Figure 2-7.
NAS CCR: Chapter 5.
IPCC 4AR WG1: Chapter 1, esp. Figure 1.3.

Originally Posted by brazil84

I don't know [if humans caused greenhouse gas increases].

Well, scientists do.

IPCC 3AR WG1: Chapter 3.4, esp. Figure 3-3.
NAS CCR: Chapter 3.
IPCC 4AR WG1: Chapter 2.3, esp. Figure 2.3, and take special note of Figure 2.3(b) and learn why ¹³C/¹²C is super-important in determining how much CO₂ comes from fossil fuels.

Originally Posted by brazil84

No [I do not accept that greenhouse gases are competent and necessary to explain warming].

On what basis? Scientists disagree with you.

Competency:
IPCC 3AR WG1: Chapter 6.13, esp. Figure 6-6.
NAS CCR: Chapter 5.
IPCC 4AR WG1: Chapter 2.1, esp. Figure FAQ 2.1

Necessity:
IPCC 3AR WG1: Chapter 12.2, esp. Figure 12-7.
NAS CCR: Chapter 5.
IPCC 4AR WG1: Chapter 9, esp. Figure 9.5.

Originally Posted by brazil84

No [I do not believe increases in temperature will cause net harm].

On what basis? Scientists disagree with you.

IPCC 3AR WG2: Chapter 2.6, esp. Figure SPM-1.
IPCC 4AR WG2: Summary for Policymakers, Figure SPM-2.

Originally Posted by brazil84

I disagree with this. For example, if we were 100% certain that it was impossible to stop CO2 levels from increasing, the other questions would be essentially academic.

The amount of hand-holding I have to do to you is irritating. If you look at the SRES scenarios, it is quite possible to stop CO₂ levels from increasing.

For someone who bills himself as having an open mind and wants to discuss the nitty-gritty of global warming, you are certainly disappointing.

[aptronym]

Originally Posted by Quartz

I'm no American, so don't have a 401k; and I'm well aware that past performance is no indication of future growth.

Yet you plan as such, do you not? Or do you have retirement money sitting in an account with zero expectation of growth?

Originally Posted by Quartz

As for the warming, I'll note that the Earth has been warming since the Little Ice Age. How much (if any) is due to man? How much (if any) is due to nature?

This is answered in my posts to brazil84, but I'll summarize.

(1) The amount that humans are "pushing" the temperature higher is currently 12x higher than the amount that natural forces are "pushing" (radiative forcing).

(2) Historically, all of the data from 1900-1950 can be explained without invoking any human causes. However, the data from 1950-2000 cannot; when you add in the expected human warming from (1), the models and observations match exactly.

Originally Posted by Quartz

If it's all - or mostly - due to man, then CO2 emissions are therefore a good thing, else we'd be in another ice age.

For now, yes, but CO₂ emissions will continue to rise, and we are well out of the Little Ice Age now. We're actually at or above the much-touted Medieval Warm Period, a period of unusual warmth.

However, as I noted to jshore a few posts up from this quote, the rate at which temperature changes is going to impact us a lot more than the absolute temperature. We (as a species and as modern, Western civilization) can probably adapt to large temperature changes, if we have enough time.

Originally Posted by Quartz

No, but we shouldn't dismiss them [scientific minority papers] either, simply because they dissent.

For scientists, you're right. 3 good papers is worth more than 650 bad papers, and for people who are knowledgeable in a subject, evidence, not popularity, rules. Not many scientists dismiss that there are minor controversies.

However, in terms of moving the debate into a public forum, given 650 papers on one side and 3 papers on the other, which side should dictate public policy? This is a little different now. How much dissent are we willing to allow to hold up action?

As examples, there are scientific papers and credible scientists that claim HIV is not the cause of AIDS; that smoking is harmless; that the World Trade Center towers in New York City could not have collapsed as a result of passenger jets. Should we stop HIV vaccine development until we're "sure"? Should we drop anti-smoking efforts because there is "scientific disagreement"? Should we hold off on assigning blame to terrorists or "teach the controversy" to be fair to both sides?

I argue no to all of these - there is enough evidence to warrant action. Perhaps the American judicial rule of "beyond a reasonable doubt" applies here.

Global warming, admittedly, is a topic much more complex than these - the consequences of inaction and the costs of action are much more nebulous. That's why it's critical for people to stop getting hung up on the simple, nearly-unanimous topics such as "Is the Earth warming?" and "Is it our fault?" and move on to "What can we do, and will it be worth doing?"

[Quartz]

Originally Posted by aptronym

(2) Historically, all of the data from 1900-1950 can be explained without invoking any human causes. However, the data from 1950-2000 cannot; when you add in the expected human warming from (1), the models and observations match exactly.

Is it not true that the models are specifically tuned to fit the past data? And in the past models which have extrapolated into the now present have been proved wrong?

However, in terms of moving the debate into a public forum, given 650 papers on one side and 3 papers on the other, which side should dictate public policy? This is a little different now. How much dissent are we willing to allow to hold up action?

You're assuming those 650 papers are good. Many are based on models, which I, for one, discredit. Others, given high publicity, like Mann's hockey-stick, have been otherwise discredited.

As examples, there are scientific papers and credible scientists that claim HIV is not the cause of AIDS; that smoking is harmless; that the World Trade Center towers in New York City could not have collapsed as a result of passenger jets. Should we stop HIV vaccine development until we're "sure"? Should we drop anti-smoking efforts because there is "scientific disagreement"? Should we hold off on assigning blame to terrorists or "teach the controversy" to be fair to both sides?

No, because the examples you give are falsifiable. And have been proven false. Current climate change theories are not falsifiable. We've had ice ages with higher CO2 levels. BTW I'm including non-CO2 climate change theories - I asked about one of the solar theories a while back.

I argue no to all of these - there is enough evidence to warrant action. Perhaps the American judicial rule of "beyond a reasonable doubt" applies here.

This is the big problem. There is actually no evidence whatsoever that our CO2 emissions are anything to do with global warming. Sure the temperature increase is coincident with increased CO2 emissions, but it's also coincident with the solar cycle - and some say that's a better longer-term fit. But correlation is not causation. Maybe they're both right; maybe they're both wrong. I don't know, but I'm thoroughly skeptical of something that has no actual evidence.

So I'll continue to question.

[Enginerd]

Originally Posted by Quartz

Is it not true that the models are specifically tuned to fit the past data? And in the past models which have extrapolated into the now present have been proved wrong?

Of course it's true that models are tuned to past conditions. How else could you calibrate a model with the degree of complexity of a GCM? How could you calibrate any model without comparing it to known conditions?

There are two important steps to using a model: calibration and validation. Calibration involves setting all the parameters of a model so that it accurately simulates a known condition, given the correct initial conditions and boundaries. you simply can't calibrate a model without specifically tuning it to past data - there's no other way to know whether it can do what you want it to do. Model validation involves taking the calibrated model, inputting a set of initial conditions, and simulating another known condition. If the model simulation predicts the known condition within the acceptable range of error (which varies depending on the field and objective of the model), it is considered "validated." There are certainly conditions associated with the validation, and a discussion those conditions is generally included in scientific publications.

In the past, models have had varying degrees of success. It's certainly true that some models have failed to accurately simulate the climate, and those models are either revised or discarded. It's also true that some models have accurately simulated parts of the climate system and the Earth's response to various driving conditions. These models, too, are continually revised to improve the precision and accuracy of the simulations.

If you're looking for a single model that has accurately simulated every component of the climate system, you're not going to find it. Ever, probably. But various models do accurately simulate different components, and the bulk of the validated models generally converge on similar results when run with similar conditions (a doubling of pre-industrial CO2 concentration, for example).

You're assuming those 650 papers are good. Many are based on models, which I, for one, discredit. Others, given high publicity, like Mann's hockey-stick, have been otherwise discredited.

Do you use public water supplies? They're based on population models, as well as hydrologic models that predict the impacts of withdrawal of water from aquifers and streams. Roadways are designed based on models that predict population growth and distribution. Hell, stores are located based on those population models, with economic factors thrown in that make them even more complex. If you reject every conclusion that's based on modeling, you're left with an incredibly simplistic view of life, and a fairly limited range of options.

And Mann's hockey stick hasn't been discredited. Rather than repeat previously posted material, I'll link to posts in brazil's earlier thread by Gigobuster and jshore.

No, because the examples you give are falsifiable. And have been proven false. Current climate change theories are not falsifiable. We've had ice ages with higher CO2 levels. BTW I'm including non-CO2 climate change theories - I asked about one of the solar theories a while back.

Cite for an ice age with elevated CO2 concentrations?

What solar theories are you asking about? The orbital cycles that affect the amount of solar radiation reaching the Earth have periodicities far too long (19,000 years is the shortest) to produce the effects we've seen over the last century, and the current estimates of solar forcing to changes in the sun itself put the temperature change over the last 100 years at about 0.2 degrees - 20% of the observed change. Is there another solar theory that you're advancing?

This is the big problem. There is actually no evidence whatsoever that our CO2 emissions are anything to do with global warming. Sure the temperature increase is coincident with increased CO2 emissions, but it's also coincident with the solar cycle - and some say that's a better longer-term fit. But correlation is not causation. Maybe they're both right; maybe they're both wrong. I don't know, but I'm thoroughly skeptical of something that has no actual evidence.

This is just plain wrong, on two fronts. First, there's your claim that there's no evidence that our CO2 don't affect the Earth's climate. This is simply mind boggling. The link between CO2 and temperature on Earth goes back at least hundreds of millions of years. In the mid-cretaceous period (100 million years ago), the average temperatures in the tropics were a few degrees warmer than they are today, while the poles were 20-40 degrees warmer - during this period, CO2 concentrations are estimated at 4-10 times today's numbers. On the flip side, CO2 concentrations during the last glaciation were significantly lower than todays values - roughly 200 ppm compared to pre-industrial values of 280 ppm and a current concentration around 380 ppm. The correlation between CO2 and temperature is clear, and the driving mechanisms of greenhouse gases and the feedback loops they cause have been explored for decades. With this correltation and the enormous increase in atmospheric CO2 over the industrial age, how can you defend your statement?

Aside from that, you're also wrong about the coincidence of temperature increases with solar cycles. The recent temperature changes (over the last 100 years) diverge from the changes that would be expected from the sum of the solar
cycles. Can you provide a cite to a peer-reviewed journal that claims there's a better fit between solar cycles and temperature than there is between CO2 and temperature?

So I'll continue to question.

Are you questioning, or are you flat out saying "that ain't true," and refusing to listen to any arguments to the contrary?

[aptronym]

Originally Posted by Quartz

Is it not true that the models are specifically tuned to fit the past data?

Yes, that is not true. As a matter of fact, the IPCC presents many such models to show that minus anthropogenic greenhouse gases, it's impossible to fit the past data.

Originally Posted by Quartz

And in the past models which have extrapolated into the now present have been proved wrong?

This is an unanswerable question.

(a) I'm sure that you could dig up some past model which would be proved wrong when extrapolated to now, but that doesn't answer the question about whether the best models have been proved wrong.

(b) In terms of climate change, there hasn't been enough time to test any model beyond statistical noise, especially the latest, and arguably best, models.

(c) If a particular model were outside its predicted range, it still wouldn't answer the question of whether the model is valid. After all, and I will assume you now agree that economic models of the stock markets are still widely used and accepted, we still use plenty of models whose short-term predictions have been torn to shreds.

Originally Posted by Quartz

You're assuming those 650 papers are good.

Why wouldn't you? Are you qualified to review climatology papers?

Originally Posted by Quartz

Many are based on models, which I, for one, discredit. Others, given high publicity, like Mann's hockey-stick, have been otherwise discredited.

You will note that only one half of one argument rests on models at all, and no arguments on a hockey stick. I've specifically excluded any mention of proxy temperature data to avoid the hockey stick argument (this upon request of brazil84 from the hockey stick threads).

Originally Posted by Quartz

No, because the examples you give are falsifiable. And have been proven false.

Absolutely wrong. That HIV causes AIDS has never been proven - only a strong (and not absolute) correlation has been shown. Most people who have AIDS have anti-HIV antibodies - but not all. Most people who are HIV(+) have or get AIDS - but not all. If we demand the same level of proof that climate change deniers demand of global warming, the only way to "prove" HIV causes AIDS would be to intentionally inject a control and experimental group with a placebo or HIV, respectively - something clearly unethical.

Correlation does not imply causation, but correlation strongly suggests causation if no other explanation can adequately explain the observations and the correlator is both competent and necessary.

Are there anomalies in the HIV/AIDS correlation? Yes; some answered, some unanswered (as listed above). Yet, we cannot find anything else that would adequately explain why 99% of the people who get HIV get AIDS and 99% of the people who have AIDS have HIV. Unless we find something, we can be strongly confident that HIV causes AIDS.

Are there anomalies in the smoking/cancer correlation? Yes; everyone has that obese uncle who chain-smoked for 80 years and finally died in a traffic accident at 93. Yet, when we correct for lifestyle factors, we cannot find anything else that would adequately explain why smokers get so much more lung cancer than non-smokers, and why such a risk increases with dose. Unless we find something else, we can be strongly confident that smoking causes lung cancer.

Are there anomalies in the planes/WTC correlation? Yes; it's unusual that the missing black boxes were never found. Yes; there were conflicting reports from different government agencies. Yes; a lot of external evidence was seized by the FBI and never declassified. Yes; the temperature of the flame might only have been hot enough to weaken, not melt, the steel beams. Yet, we cannot find anything else that would adequately explain why the towers collapsed after getting hit by planes. Unless we find something else (and Lord knows people have tried), we can be strongly confident that the plane impacts caused the towers to fall.

Likewise, are there anomalies in the GHG/AGW correlation? Yes; in the Milankovitch cycles CO₂ seems to lag, not lead, temperature increases (explanations available). Yes; there are unanswered questions about solar flux verses solar dimming. Yes; many of the early temperature measurements were taken in urban heat islands (which actually works in favor of the AGW argument because it would increase later temperature changes which are more attributable to human activity). Despite all of this, we cannot find anything else which would adequately explain why the Earth is warming to this degree. Unless there are factors which are both competent and necessary that have not been addressed (and the IPCC has addressed many), we can be strongly confident that anthropogenic emissions have caused global warming.

Originally Posted by Quartz

Current climate change theories are not falsifiable.

Sure it's falsifiable - return to pre-Industrial times, see if temperatures level off, and then restart industry to see whether temperatures keep climbing.

Originally Posted by Quartz

We've had ice ages with higher CO2 levels.

Definitely false in the past 400,000 years. The Vostok ice core shows the last Milankovich cycles to oscillate between 200 ppm and 300 ppm CO₂ - current levels are 380 ppm. Probably false in the past 50,000,000 years - isotopic measurements in rock sediment shows a big decrease from the Jurassic, but has been low since then. You need to go back a good 100,000,000 years to find a time when we had demonstrably higher CO₂ levels than we do now. Modern humans (25,000 years old?) have definitely never seen this much CO₂ in the air.

Originally Posted by Quartz

There is actually no evidence whatsoever that our CO2 emissions are anything to do with global warming. Sure the temperature increase is coincident with increased CO2 emissions, but it's also coincident with the solar cycle

I'm not entirely sure which solar cycle you're talking about - there are many, and the shortest of which is 11 years. But in any case this is a question with a definite answer: radiative forcing. We know exactly how much more sunlight we're seeing. It's quantified and in the IPCC diagrams. Likewise, we know how much CO₂ is forcing. It's quantified and in the IPCC diagrams. The net anthropogenic forcing is 12x higher than the natural forcing - yes, both are pushing us warmer, but one is pushing 12x harder.

Originally Posted by Quartz

I'll continue to question.

Questioning is fine, so long as you don't shut your eyes to the evidence. I've taken a decent chunk of time to point you and brazil84 to the exact chapters in the IPCC reports and NAS report so that you can see (a) the evidence, and (b) whether the evidence supports their conclusions.

[Quartz]

Originally Posted by Enginerd

And Mann's hockey stick hasn't been discredited. Rather than repeat previously posted material, I'll link to posts in brazil's earlier thread by Gigobuster and jshore.

Then why did he have to publish a corrigendum (pdf) which admitted that it failed rigorous statistical validation and used invalid proxies (amongst other issues)?

Cite for an ice age with elevated CO2 concentrations?

Earth's distant past. Hundreds of millions of years ago.

What solar theories are you asking about?

Sunspots is one. The Maunder minimum is coincident with the Little Ice Age. A clip from an article by Dr David Whitehouse:

Originally Posted by Dr Whitehouse

Dalton Solar Minimum (1790-1820) - global temperatures are lower than average.

Maunder Solar Minimum (1645-1715) - coincident with the 'Little Ice Age'.

Spoerer Solar Minimum (1420-1530) - discovered by the analysis of radioactive carbon in tree rings that correlate with solar activity - colder weather. Greenland settlements abandoned.

Wolf Solar Minimum (1280-1340) - climate deterioration begins. Life gets harder in Greenland.

Medieval Solar Maximum (1075-1240) - coincides with Medieval Warm Period. Vikings from Norway and Iceland found settlements in Greenland and North America.

Oort Solar Minimum (1010-1050) - temperature on Earth is colder than average.

Now, I find this interesting, but not compelling. Interesting because it provides a reason for why we came out of the Medieval Warm Period and the Little Ice Age. But one reason I don't find it compelling is that I've read elsewhere (sorry, it was in a book long ago, so no link) that the MWP may have been ended by a massive volcanic eruption. Another is that it's not a perfect fit. A third is this pdf (which I found hard going) which only shows a suggestion (due to insufficient data) of a correllation between the Maunder Minimum and the Wolf and Spoerer Minima. And, of course, the Little Ice Age lasted over 300 years, vastly longer than any of the aforementioned minima.

BTW if anthropogenic CO2 is responsible for GW, but only in the last 100 years or so, what did cause the Earth to come out of the Little Ice Age?

The orbital cycles that affect the amount of solar radiation reaching the Earth have periodicities far too long (19,000 years is the shortest)...

I'm not talking of the Milankovich cycles.

This is just plain wrong, on two fronts. First, there's your claim that there's no evidence that our CO2 don't affect the Earth's climate.

But I didn't say that. I said that there's no evidence that the CO2 we've produced is responsible for the warming we've seen. That's much more specific.

Are you questioning, or are you flat out saying "that ain't true," and refusing to listen to any arguments to the contrary?

I'm questioning: the AGW movement is based on the link between human-produced CO2 and global warming, but that link simply has not been shown. I personally questioned Lord May, a past President of the Royal Society, on this last year, after he'd given a speech which touched on Global Warming, and he was unable to gainsay me. Of one thing I am sure: the record shows that the only constant is change. To assert that the current change is down to us is bold. Not necessarily wrong, but bold nonetheless.

[jshore]

I'll just throw in a couple additional comments.

Originally Posted by Quartz

Is it not true that the models are specifically tuned to fit the past data? And in the past models which have extrapolated into the now present have been proved wrong?

Originally Posted by Enginerd

Of course it's true that models are tuned to past conditions. How else could you calibrate a model with the degree of complexity of a GCM? How could you calibrate any model without comparing it to known conditions?

Originally Posted by aptronym

Yes, that is not true. As a matter of fact, the IPCC presents many such models to show that minus anthropogenic greenhouse gases, it's impossible to fit the past data.

Let me try to bridge the gap between these answers. Climate models are not statistical models or models with a lot of fitting parameters. They are mechanistic models based on the physical processes in the atmosphere, oceans, etc. That said, it is not possible to represent all such processes from first principles, e.g., things with clouds that occur on scales smaller than the model resolution so there are some parameterizations for things like these.

However, it is important to understand that such parameters are generally adjusted to get basic features of the process in question correct or, in a few cases, to get some basic climatological things correct. However, there are many, many more degrees of freedom than there are parameters...so, the models cannot in any way be "tuned" to fit the massive volume of available data. Furthermore, none of this sort of parameter tuning will really be able to tune (say) the time-dependence of the global temperature record.

There is a famous aphorism in physics due to somebody or other that says "Give me four parameters and I can fit an elephant. Give me five and I can make it wag its tail." (You can also find versions on the web with the numbers 3 and 4 or the numbers 5 and 6.) At any rate, it is true that if we wrote up some simple functional dependence T = f(t) where T is global temperature and t is time and chose the function f(t) well with several free parameters, we could probably do a decent job in fitting the instrumental temperature record. However, this is in no way what the models are actually doing.

If one thinks they are in some convoluted way doing this, then there would be an easy way to demonstrate this: Namely, you could take one of the climate models (at least one if not several are publicly available) and "tune" the parameters so that the global temperature vs. time is well-fit without having the greenhouse gas forcing in the model, i.e., simply using the natural forcings. I think the fact that this has not been done speaks volumes.

Originally Posted by Enginerd

What solar theories are you asking about? The orbital cycles that affect the amount of solar radiation reaching the Earth have periodicities far too long (19,000 years is the shortest) to produce the effects we've seen over the last century, and the current estimates of solar forcing to changes in the sun itself put the temperature change over the last 100 years at about 0.2 degrees - 20% of the observed change.

Worse yet, the time-dependence isn't right. I.e., there is no way to explain the warming that started about 1970 and has continued since then.

[jshore]

Originally Posted by aptronym

Definitely false in the past 400,000 years. The Vostok ice core shows the last Milankovich cycles to oscillate between 200 ppm and 300 ppm CO₂ - current levels are 380 ppm. Probably false in the past 50,000,000 years - isotopic measurements in rock sediment shows a big decrease from the Jurassic, but has been low since then. You need to go back a good 100,000,000 years to find a time when we had demonstrably higher CO₂ levels than we do now. Modern humans (25,000 years old?) have definitely never seen this much CO₂ in the air.

A couple of nitpicks:

(1) The ice core data for CO₂ now goes back 650,000 years (published) and apparently 800,000 years (unpublished but presented at the AGU meeting).

(2) I think your numbers for when CO₂ was likely higher than now are a little off. A graph in the IPCC third assessment report that showed CO₂ over different timescales suggests that it gets above current levels once you go back about 23 million years ago. Of course, whether it was 23 million years ago, 50 million years ago, or 100 millions years ago when it was last higher is not too relevant. All of those numbers are well-before homo sapiens were around (or anything particularly close to homo sapiens).

[jshore]

Originally Posted by Quartz

Then why did he have to publish a corrigendum (pdf) which admitted that it failed rigorous statistical validation and used invalid proxies (amongst other issues)?

The corrigendum says nothing of the sort. It mainly just notes mistakes that were made in recording which data was used in the Supplementary Information published online along with the paper. There is hardly a paper published that does not contain some sort of typographical error or incorrect or incomplete description of data used, or something of the sort. The concluding sentence of that corrigendum says: "None of these errors affect our previously published results."

Earth's distant past. Hundreds of millions of years ago.

There are a few points to make here:

(1) It is very hard to get accurate measurements of CO2 levels at the necessary resolution going back that far. As aptronym noted, excellent CO2 data is available as long as the ice core data go back (now 800,000 years). Beyond that, the available data are much less time-resolved and much less certain.

(2) Of course, noone is claiming that CO2 is the only factor that affects climate. There are many other factors, particularly on geological timescales. For example, I believe that the sun has generally been trending brighter over time on the billion year timescale. Also, continents and mountain ranges were in different locations tens or hundreds of millions of years ago, which can have profound climatological effects. While it is interesting to study the various factors that affected climate on these timescales, it is in many respects much harder than looking over the timescale of the last 800,000 years for which very good data is available and for which most of these geological factors haven't changed very significantly.

(3) Here is an article by two people who are experts in paleoclimatology. Note that their conclusion is that, if anything, climate models may be underestimating the sensitivity of the climate to perturbing forcings, such as the known forcing that we are producing by the added greenhouse gases.

Sunspots is one. The Maunder minimum is coincident with the Little Ice Age. A clip from an article by Dr David Whitehouse:

Noone disagrees that solar activity affects the climate. However, the question is whether the current warming can be explained by solar activity, and the evidence overwhelmingly argues that it can't be.

As for sunspots in particular, there was a famous paper from the early 1990s argued for a correlation between sunspot cycle length and global temperature...and was (and still is) popular in skeptic circles. However, more recently, one of co-authors has revisited the more recent data and has found that the correlation breaks down dramatically since ~1980, with the climate continuing to warm while the sunspot cycle length remains flat. (There have also been papers, e.g., here, that have shown that the correlation was never really as good as it was claimed to be in the first place.)

To assert that the current change is down to us is bold. Not necessarily wrong, but bold nonetheless.

It is not an assertion that has been arrived at lightly. The first calculations of the warming effect due to a hypothetical doubling of CO2 in the atmosphere go back over 100 years to Arrhenius. When James Hansen first announced to the world in the late 1980s that the effects of greenhouse gases had emerged from the noise, the scientific community as a whole was initially skeptical. However, 20 more years and lots more data, modeling, and other studies have convinced nearly all of them that this is in fact correct. The story of the discovery of AGW is an example of a hypothesis that spent a lot of time being pretty much ignored or dismissed by the scientific community. It is only once the evidence became more and more clear that they were won over.

[Enginerd]

Originally Posted by Quartz

Then why did he have to publish a corrigendum (pdf) which admitted that it failed rigorous statistical validation and used invalid proxies (amongst other issues)?

Did you read your cite? Mann, et al. published more complete data sets, corrected some errors in their original work, and provided a fuller description of their methodology. Did you happen to catch the last sentence of the corrigendum? "None of these errors affect our previously published results."

But don't take their word for it - check with the U.S. National Academy of Sciences. The publication of a corrigendum doesn't necessarily invalidate a paper - it can, but it depends on the contents of the corrigendum and the other available data.

Earth's distant past. Hundreds of millions of years ago.

There's nothing in that cite about the CO2 concentration during "Snowball Earth" - just an overview of the (controversial) hypothesis. Do you have any cite for the atmospheric CO2 concentration that long ago? Preferably one that's been peer-reviewed, and isn't found on the website of a telephone psychic.

Sunspots is one. The Maunder minimum is coincident with the Little Ice Age. A clip from an article by Dr David Whitehouse:

[Whitehouse's comments snipped - Eng.]

Now, I find this interesting, but not compelling. Interesting because it provides a reason for why we came out of the Medieval Warm Period and the Little Ice Age. But one reason I don't find it compelling is that I've read elsewhere (sorry, it was in a book long ago, so no link) that the MWP may have been ended by a massive volcanic eruption. Another is that it's not a perfect fit. A third is this pdf (which I found hard going) which only shows a suggestion (due to insufficient data) of a correllation between the Maunder Minimum and the Wolf and Spoerer Minima. And, of course, the Little Ice Age lasted over 300 years, vastly longer than any of the aforementioned minima.

Is there evidence of greater solar radiation over the last century? Everything I've seen attributes about 0.2 degrees to increased insolation; that leaves 0.4 to 0.6 degrees (depending on your estimate) of warming unexplained.

The article you linked to discusses the influence of solar radiation on production of the Cl-36 isotope. The upshot is that the two appeared to be linked, but local variations in the Cl-36 concentrations during periods of relatively constant insolation show that other factors impact this concentration. The article doesn't link the Cl-36 to climate effects, and doesn't discuss Cl-36 trends outside of the ones that it links with the sunspot minima. I'm not sure what role you think it plays in this discussion.

BTW if anthropogenic CO2 is responsible for GW, but only in the last 100 years or so, what did cause the Earth to come out of the Little Ice Age?

There are any number of feedback loops that can magnify the effects of small changes. Changing temperatures can cause changes in atmospheric circulation, which leads to differences in global heat transport. Since the Little Ice Age appears to be more a regional phenomenon than a global one (records from the northern hemisphere show a pronounced effects, without analogous signals in Antarctic ice cores), the regional temperature changes could certainly have induced circulation shifts. The sunspot activity may well have contributed to this (both the cooling and subsequent warming), but it's not sufficient on its own to drive the entire process.

But I didn't say that. I said that there's no evidence that the CO2 we've produced is responsible for the warming we've seen. That's much more specific.

I don't really know how to respond to this. It's simply wrong.

I'm questioning: the AGW movement is based on the link between human-produced CO2 and global warming, but that link simply has not been shown. I personally questioned Lord May, a past President of the Royal Society, on this last year, after he'd given a speech which touched on Global Warming, and he was unable to gainsay me. Of one thing I am sure: the record shows that the only constant is change. To assert that the current change is down to us is bold. Not necessarily wrong, but bold nonetheless.

I wonder if Lord May was as unable to answer you as jshore, aptronym, kimstu, and others who've been posting in these threads. What would it take, in your eyes, to answer that question?

[Quartz]

Originally Posted by Enginerd

I wonder if Lord May was as unable to answer you as jshore, aptronym, kimstu, and others who've been posting in these threads. What would it take, in your eyes, to answer that question?

Actual evidence. Not models, evidence.

[Capt. Ridley's Shooting Party]

And what form would this evidence take? Let's face it, there is no evidence that will convince you. If you wish to throw out the use of models, then you wish to throw out science. Models are central to nearly all branches of science, from AI research to epedemiology.

[brazil84]

Originally Posted by aptronym

Sounds really evasive, but okay.

As I said in the other thread, I prefer not to get sidetracked here.

Skepticism is fine - the basis of science is skepticism. Skepticism, however, implies that should evidence be presented, you could be convinced. Later in your reply you specifically dismiss all the evidence without any reason - that isn't skepticism, that's ignorance.

What are you talking about? The only calculation you present doesn't even include a variable for CO2. Please give me a cite that the estimated size of warming due to CO2 (based on a simple calculation from first order principles) matches the size of the observed effect.

Because of skepticism. One proof of anthropogenic global warming isn't enough.

I doubt it. If it were possible to demonstrate the currently popular CO2 AGW theory with a first order calculation (and without models that incorporate positive feedback loops) the warmers would be screaming about it from the rooftops.

But just give me a cite.

Yet, you are not debating the substantiative issues and dismissing the IPCC data on an unknown basis.

Of course I'm debating the substantive issues. What do you think I'm posting about?

I misunderstood you because sensitivity is a specifically defined term in climatology - a 1.1-2.9^oC range is insensitive because the variability between runs (1.3^oC) is small and a 2.4-6.4^oC range is sensitive because the variability between runs (4.0^oC) is large.

I think you're incorrect here, but there's no need to argue over semantics. By "sensitive" I am referring to sensitivity to CO2. A model that predicts a lot of warming for a certain increase in CO2 levels is sensitive. A model that predicts less warming for the same increase is less sensitive.

Technological singularity or not, it's impossible to compare two values unless you actually know both values.

That's incorrect, as I mentioned in my economic growth thread. If you know the Owner's Equity of a corporation, it's possible to compare Assets and Liabilities without knowing the actual values of those two quantities. It's simple mathematics.

On what basis do you contest the instrumental temperature record?

There have been land use changes near many temperature monitoring stations. This may have screwed up the instrumental record.

And since I am now openly doubting whether you've even seen the evidence before dismissing it, I am citing exactly which figures and chapters to read so that you have no more excuses.

Can you please quote the selections you believe are important? Thanks!!

The amount of hand-holding I have to do to you is irritating. If you look at the SRES scenarios, it is quite possible to stop CO₂ levels from increasing.

Can you quote the selection you believe supports this position?

Here's what Cecil Adams said on the subject:

Is the solution, then, to rein in the developing nations? Hardly. While we can advise countries such as China and India on ways to use energy more efficiently, we can't seriously expect them to halt their efforts to achieve the prosperity we already have--and make no mistake, it's precisely those efforts that are driving up carbon emissions. China alone supposedly expects to add 15,000 megawatts of electric power capacity every year.

http://www.straightdope.com/columns/060407.html

Now, perhaps Cecil is wrong. But it's not necessarily unreasonable to consider the questions out of order.

[aptronym]

Originally Posted by Quartz

Sunspots is one. The Maunder minimum is coincident with the Little Ice Age. A clip from an article by Dr David Whitehouse ... Now, I find this interesting, but not compelling. ... And, of course, the Little Ice Age lasted over 300 years, vastly longer than any of the aforementioned minima.

This is not a reply to your quote, but rather an interesting observation -- recorded sunspot history only goes back a few hundred years. Early observations suffer from the same problems that early temperature observations suffer from - people didn't do things as well as we do now. Most of the solar minima that you cited, as well as the whole concept of a "Little Ice Age", come from proxy data fitted with mathematical modeling.

Why is it that you're so quick to accept models of solar activity and temperature reconstruction, but not climatological models?

Originally Posted by Quartz

I said that there's no evidence that the CO2 we've produced is responsible for the warming we've seen. That's much more specific.

But there is. My first post is full of that evidence; my previous post to brazil84 has even more.

Perhaps you are confusing "I don't understand the evidence" with "There is no evidence"? The only explanation I can think of is that you just don't see the connection between radiative forcing (snooze, snooze) and global warming.

[Siam Sam]

My question about the effects of global warming has to do with the melting of the ice caps. I understand about rising sea levels and such, but I was always led to believe that we needed the polar-ice regions to help regulate life on Earth. Something about their cooling effect. The mechanics of this escapes me now, but suffice it to say that years ago, pre-global-warming concerns, I read this. So, if all of the ice were to melt -- and I mean all of it, Antarctica, the Arctic, everywhere -- would survival still be possible?

My main concern with global warming is the survival of our species. I figure global warming is NOT going to be reversed, snappy slogans notwithstanding, and so I hope that after a century or two, we'll get into the swing of the new pattern.

[aptronym]

Originally Posted by brazil84

The only calculation you present doesn't even include a variable for CO2. Please give me a cite that the estimated size of warming due to CO2 (based on a simple calculation from first order principles) matches the size of the observed effect.

Before I post it, let me first berate you for not reading carefully. 99% of your complaints in this thread now come directly from refusing to read what is posted to you, what is linked to you, and what is cited to you.

I seriously question any sort of intellectual honesty you have.

Quoting from Post #1 in this thread (not using the quote function to keep the formatting consistent)
"based on Earth's distance from the Sun and the Stefan-Boltzmann blackbody radiation law, Earth should be a frigid -15^oC on average. Yet its average temperature is +20^oC - a 35^oC warming which is due to greenhouse gases - about 95% due to water (H₂O), and 5% due to carbon dioxide (CO₂), with all the rest of the gases contributing some miniscule amount. If the greenhouse effect were to be doubled, water would start spontaneously boiling in the tropics, and if the greenhouse effect were to be eliminated, water would freeze everywhere except for the tropics.

Not surprisingly, increasing the CO₂ (or H₂O, but we don't generate enough) will increase the greenhouse effect. This difference is anthropogenic global warming. Experimentally, we're seeing a 38% increase in CO₂ levels since the Industrial Revolution, which, if the greenhouse effect were linear, would correspond to about a 0.7^oC warming. Just to be clear, the greenhouse effect is certainly not linear, but we're in the right ballpark here."

Originally Posted by brazil84

If it were possible to demonstrate the currently popular CO2 AGW theory with a first order calculation (and without models that incorporate positive feedback loops) the warmers would be screaming about it from the rooftops.

I HEREBY SHOUT IT FROM THE ROOFTOP - READ THE OP, IT CONTAINS A FIRST-PRINCIPLE CALCULATION WITHOUT ANY MODELS THAT SHOWS THE MAGNITUDE AND DIRECTION OF OBSERVED CO₂ LEVELS MATCHES THE INCREASE IN GREENHOUSE EFFECT!

Is that good enough for you? Is there any way I can make this any clearer to you?

Originally Posted by brazil84

Of course I'm debating the substantive issues. What do you think I'm posting about?

I think you have spent 80% of your time desperately trying to bring in the hockey stick into this conversation and 20% of your time asking for citations of things I have already cited.

Originally Posted by brazil84

I think you're incorrect here, but there's no need to argue over semantics. By "sensitive" I am referring to sensitivity to CO2. A model that predicts a lot of warming for a certain increase in CO2 levels is sensitive. A model that predicts less warming for the same increase is less sensitive.

Thus, it is unsurprising that, if you define "sensitive" as "increases with CO₂", that the increase in CO₂ would be largest with the most "sensitive" models.

It also occurred to me that another fundamental misunderstand you might have is that you think all the models predict the same CO₂ increases. You'd be wrong - read the descriptions of the SRES in the IPCC reports; they list not only the expected CO₂ rise for each SRES, but also a bunch of other factors.

Either way, I'd like to point out as a theme that both the definition of "sensitivity" and the description of CO₂ levels in each SRES are linked in the first post of this thread.

Originally Posted by brazil84

If you know the Owner's Equity of a corporation, it's possible to compare Assets and Liabilities without knowing the actual values of those two quantities. It's simple mathematics.

Is this a specific example that works, or is it a general example? Do you honestly believe that any two values can be compared if their magnitudes aren't known, or do you simply think that the case you're citing can be applied to this case?

Originally Posted by brazil84

There have been land use changes near many temperature monitoring stations. This may have screwed up the instrumental record.

Okay, so how do you contest the satellite temperature record which matches the instrumental temperature record from 1980-2000?

Originally Posted by brazil84

Can you please quote the selections you believe are important? Thanks!!

I've already quoted the selections that I believe are important. You don't exude enough intellectual honesty to make me believe that you're not just trying to waste people's time.

I'll make you a deal - you show one example of having read any portion of the IPCC 3AR, NAS CCR, or IPCC 4AR by addressing one passage (either supporting it by rephrasing it or by bringing up a non-obvious question) which has not already been quoted on this thread.

In return, I will quote the exact selections that are important.

Originally Posted by brazil84

Can you quote the selection you believe supports this position?

Yes, I could. But I'd be half-tempted to fabricate a quote just to see whether you fact-check.

Originally Posted by brazil84

Here's what Cecil Adams said on the subject ... it's not necessarily unreasonable to consider the questions out of order.

Ah, but this thread is not about considering the questions out of order - that was a topic that was brought up in your "Economic hockey stick" thread in which you specifically said that you were willing to consider the climatological evidence for anthropogenic global warming without any discussion of the economics of stopping it.

Originally Posted by brazil84

perhaps Cecil is wrong

Cecil is exactly right for the exact question he is answering: "Is Kyoto a good treaty?" And the answer is, correctly, no. At the present time, emissions are proportional to economic output; at the present time, there is no way to cut emissions without cutting economic output. Hence, Kyoto will not work as a treaty so long as emissions are proportional to economic output.

However, if there comes a day when we can cut emissions without hurting our economy, Cecil would have to change his answer. Whether that day is now is a whole other debate.

Don't you dare think about turning that question into the topic of this thread. In the FIRST POST OF THIS THREAD ATTENTION BRAZIL84 READ THIS NEXT PART CAREFULLY BECAUSE YOU SEEM TO HAVE MISSED IT THE FIRST TIME I specifically stated:

"Things not to be discussed:
(1') I believe there is a giant conspiracy between the ACLU, the Illuminati, NAMBLA and scientists to bring about the New World Order using global warming to crush democracy and freedom.
(2') Any solution we implement is going to have to involve China and India.
(3') It's going to cost too much to fix global warming."

[Quartz]

Originally Posted by aptronym

Why is it that you're so quick to accept models of solar activity and temperature reconstruction, but not climatological models?

But I'm not. As I said, I don't find it compelling. And reconstructions are different from models - neither of us argue the temperatures reconstructed from the ice cores, do we?

The only explanation I can think of is that you just don't see the connection between radiative forcing (snooze, snooze) and global warming.

The problem I have is that I see the correlation (that it might), but not the link that demonstrates the causation (that it does).

For instance, Enginerd thusly dismissed the end of the Little Ice Age:

Originally Posted by Enginerd

There are any number of feedback loops that can magnify the effects of small changes. Changing temperatures can cause changes in atmospheric circulation, which leads to differences in global heat transport.

We're only at the temperature of the MWP. And that wasn't caused by AGW, was it?

[aptronym]

Originally Posted by Siam Sam

My main concern with global warming is the survival of our species.

I guarantee you (and I believe 99% of scientists would agree with this guarantee) that there is a 0% chance of anthropogenic global warming causing the extinction of the human species.

Keep in mind that this guarantee does not include displacement of hundreds of millions from flooded lowlands, worldwide starvation due to drought, spread of tropical diseases into currently-temperate areas, or massive migrations into subpolar regions. All I'm guaranteeing is that 15 men and 15 women capable of reproducing will survive and find each other.

I don't think you really want to make survival of a species your main concern - I think that our species would also survive a nuclear weapon detonated in a major U.S. city, but I would still advocate taking steps to reduce the probability of that happening. I would (1) first make sure the possibility is real, (2) find out how the possibility increases or decreases with our actions, (3) weigh the cost of inaction against the cost of action, and (4) try to gather everyone who would be affected to forumlate an action plan.

I advocate doing nothing less for anthropogenic global warming.

This thread is about whether global warming is (a) real, and/or (b) anthropogenic, and/or (c) harmful. I am specifically excluding discussion about how much it might cost to fix any problems, what technological developments might be needed, as well as discussion about what other nations would have to do to make a plan work. This is meant as a science thread.

[aptronym]

Originally Posted by Quartz

neither of us argue the temperatures reconstructed from the ice cores, do we?

Yes - you do. The evidence for a Medieval Warming Period and a Little Ice Age is only made possible by examing temperature proxies. If you reject proxy temperature data, then you cannot make any claims about what the temperature was like before 1850.

Originally Posted by Quartz

The problem I have is that I see the correlation (that it might), but not the link that demonstrates the causation (that it does).

I'd like to clarify your position.

Do you agree that humans are the major reason for increases in greenhouse gases? (IPCC 3AR WG1: Chapter 3.4, esp. Figure 3-3; NAS CCR: Chapter 3;
IPCC 4AR WG1: Chapter 2.3, esp. Figure 2.3, and take special note of Figure 2.3(b))

Do you agree that greenhouse gases cause global warming? (first-principles derivation in post #1 and repeated in post #38; also IPCC 3AR WG1: Chapter 6.13, esp. Figure 6-6; NAS CCR: Chapter 5; IPCC 4AR WG1: Chapter 2.1, esp. Figure FAQ 2.1)

[elucidator]

I like it when the argument gets over my head. But what that has to mean is that the issue is arguable, reasonable, and that contrary arguments exist. Arguments which involve math, and lots of it!

OK. so lets say that the situation is not nearly so desperate as us eco-fanatics insist. Lets just take that as a given.

But it might be. It's like the Heidelburg Uncertainty Thing. Maybe yes, maybe no.

But if we put the energy into it, the research, the brain power, we might just do it. Green clean energy may be possible. Or it may not.

But would you bet a dollar, flip a coin, if the payoff was a million if it's heads?

[aptronym]

Originally Posted by elucidator

But would you bet a dollar, flip a coin, if the payoff was a million if it's heads?

This thread is specifically about what the probability of heads and tails are and whether there is a positive payoff at all; I strongly object to any discussion about how much we'd bet and how big that payoff is because those are not strictly climatological questions.

It very well may be that global warming is real, anthropogenic, and harmful, but too expensive to solve - but this thread is only about the first three, because (1) scientists can only agree on the first three, and (2) the fourth question involves economics as well as politics.

[elucidator]

Gee, guy. Sorry.

[Siam Sam]

Originally Posted by aptronym

I guarantee you (and I believe 99% of scientists would agree with this guarantee) that there is a 0% chance of anthropogenic global warming causing the extinction of the human species.

Keep in mind that this guarantee does not include displacement of hundreds of millions from flooded lowlands, worldwide starvation due to drought, spread of tropical diseases into currently-temperate areas, or massive migrations into subpolar regions. All I'm guaranteeing is that 15 men and 15 women capable of reproducing will survive and find each other.

Thanks for your answer. I'm sure there will be massive displacements. That's why I mentioned a century or two afterward. By that time, I figure things will have settled down and people can get on with things. Personally, I see zero chance of stopping climate change. It's just not going to happen. People and governments will still be discussing what to do right up to when the last ice particle melts.

[jshore]

Originally Posted by Siam Sam

My question about the effects of global warming has to do with the melting of the ice caps. I understand about rising sea levels and such, but I was always led to believe that we needed the polar-ice regions to help regulate life on Earth. Something about their cooling effect. The mechanics of this escapes me now, but suffice it to say that years ago, pre-global-warming concerns, I read this.

I think what you are probably talking about, at least in part, is the idea the the parts of the earth covered by ice sheets and glaciers is much more reflective than the part by water or land. Hence, when these melt, the earth's average albedo (reflectance) decreases somewhat, which means more solar energy is absorbed making things warmer still. This is what is called a "positive feedback effect" because a warming effect causes a feedback that causes further warming.

It also means that there is what is called "hysteresis" in the system, which means that we can't necessarily, say, cool the earth down to where it was before pre-industrial times simply by reducing greenhouse gases back to pre-industrial levels once, say, the Greenland ice sheet has melted. In particular, if we did that, the Greenland ice sheet would not necessarily just come back (or, if it did, it would take an awfully long time).

On the part about whether survival would be possible if we melted all of the ice sheets, well, I don't think we would go extinct but it would certainly create huge stresses on our society and on the environment that would be quite devastating (and that I imagine could lead to a sort of breakdown of society and increase the risks of nuclear wars or other horrific conflicts). And, I believe if all the ice melted, sea levels would rise a couple hundred feet, which in many places translates to the ocean advancing tens to hundred of miles inland. The good news though is that noone really thinks we will be able to melt the East Antarctic ice sheet. We may be able to melt the West Antarctic Ice sheet and Greenland, each of which could raise the sea levels by about 20 or so feet. How rapidly that could occur is the subject of debate now...Scientists used to believe it would take millenia but there is some who now argue it could occur considerably faster.

Personally, I see zero chance of stopping climate change. It's just not going to happen. People and governments will still be discussing what to do right up to when the last ice particle melts.

Well, I am somewhat more optimistic on this than you. I think it is a huge challenge but one that we can meet...and that will, once we seriously give the market the incentives to develop the necessary technologies, may turn out to be less difficult than we imagined.

[Triskadecamus]

Well, I for one intend to reference the "Heidelburg Uncertainty Thing" a lot more, in the future.

Tris

[Mosier]

I hate to hijack the thread, but how does melting ice increase sea level? Ice takes up more volume than liquid water, so wouldn't the sea levels drop when all the displacement-causing ice melts?

[Enginerd]

Originally Posted by Mosier

I hate to hijack the thread, but how does melting ice increase sea level? Ice takes up more volume than liquid water, so wouldn't the sea levels drop when all the displacement-causing ice melts?

Melting sea ice won't raise the water level, but the ice sheets on Greenland and Antarctica aren't currently displacing any water. The Greenland Ice Sheet is about 1100 km wide and 2400 km long, and is more than 3 km thick at it's peak - it contains more than 2.3 cubic km of ice. If it completely melts, it's expected to raise sea level by 7 meters.

The Antarctic Ice Sheet is even bigger - about 30 million cubic km. The mass of ice in the Antarctic Ice Sheet is equivalent to about 70 meters of sea level.

[Triskadecamus]

     Some of the ice is piled up a mile deep on land.

     Also, as the ice that is floating melts, the temperature of the ocean will rise some. Higher temperatures for three thousand meters of water will result in some expansion of the entire mass of water proportional with the temperature increase. The exact amount of expansion that is to be expected is a nontrivial problem, even ignoring climatologic expectations of highly divergent predictions. The problem is subject to some very controversial differences of opinion among oceanologists about how the various currents exchange thermal energy. No one predicts zero expansion. But the lower values reported are sometimes only scientifically non zero.

Tris

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Not to mention the Heidelberg Uncertainty Thing.