brazil84's Global Warming Thread

Great Debates
1

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[sup]o[/sup]C per century in recent history, current warming is 1[sup]o[/sup]C 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[sup]o[/sup]C on average. Yet its average temperature is +20[sup]o[/sup]C - a 35[sup]o[/sup]C warming which is due to greenhouse gases - about 95% due to water (H[sub]2[/sub]O), and 5% due to carbon dioxide (CO[sub]2[/sub]), 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 CO[sub]2[/sub] (or H[sub]2[/sub]O, 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 CO[sub]2[/sub] levels since the Industrial Revolution, which, if the greenhouse effect were linear, would correspond to about a 0.7[sup]o[/sup]C 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 CO[sub]2[/sub], CH[sub]4[/sub], NO[sub]x[/sub]'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[sup]o[/sup]C 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[sup]o[/sup]C and sea level rises of 10-23".

Concurrent with this warming will be a host of effects, starting with “increased coral bleaching” around +1[sup]o[/sup]C, progressing to agricultural shifts around +2[sup]o[/sup]C (decreases in low latitudes and increases in high latitudes), increased coastal flooding around +3.5[sup]o[/sup]C, and “substantial burden on health services” at +4.5[sup]o[/sup]C.

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[sup]o[/sup]C warming … on the other hand, there’s also a 5% chance that we’d see a disasterous +6.4[sup]o[/sup]C 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[sup]o[/sup]C 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.

2

An excellent post.

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

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

Sorry. Cherry picking is not valid at all.

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

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…

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.

3

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

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?

Do you have a cite for that?

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

4

I’m not entirely sure which figure you’re referring to, the 38% CO[sub]2[/sub] rise or the 0.7[sup]o[/sup]C 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 “CO[sub]2[/sub] is a minor gas and cannot affect global climate” is false. The order of magnitude of the observed effect is correct.

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.

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.

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.

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?

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

Half of the second half of my argument, yes. The first half revolves around radiative forcing - we know from first principles that CO[sub]2[/sub] 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.

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.

5

http://www.columbia.edu/~jeh1/mailings/20071210_GISTEMP.pdf (.pdf)

6

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

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.

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).

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.

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.

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.

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.

7

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

Do you have a cite for that?

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.

8

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?

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?

9

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?

10

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?

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[sub]in[/sub] = E[sub]out[/sub]
φ[sub]Sun[/sub]f[sub]Sun->Earth[/sub]f[sub]absorbed[/sub] = φ[sub]Earth[/sub]
σT[sup]4[/sup][sub]Sun[/sub]4πr[sup]2[/sup][sub]Sun[/sub](πr[sup]2[/sup][sub]Earth[/sub]/4πD[sup]2[/sup][sub]Earth[/sub])(1-A[sub]Earth[/sub] = σT[sup]4[/sup][sub]Earth[/sub]4πr[sup]2[/sup][sub]Earth[/sub]
T[sub]Earth[/sub] = T[sub]Sun[/sub](r[sub]Sun[/sub]/2D[sub]Earth[/sub])[sup]1/2[/sup](1-A[sub]Earth[/sub])[sup]1/4[/sup] = 5,778*(6.955x10[sup]8[/sup]/2/1.496x10[sup]11[/sup])[sup]1/2[/sup]*(1-0.367)[sup]1/4[/sup] = 248 K (-25[sup]o[/sup]C).

Actual temperature of the Earth: 287 K (+14[sup]o[/sup]C, +39 K from predicted)

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.

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

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.

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.

11

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

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.

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.

12

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.

13

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[sup]o[/sup]C, 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.

14

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).

15

Ask me in that thread and I will answer.

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?

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?

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.

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.

Where did I say these things?

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

I don’t know.

No.

No.

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.

16

And what I was after. Thank you.

I agree that it’s an excellent sign.

This is actually a significant deviation.

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.

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?

They’re the UK government’s weather service.

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

17

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.

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:

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?

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:

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

18

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

Ein = Eout
[symbol]f[/symbol];SunfSun->Earthfabsorbed = [symbol]f[/symbol];Earth
[symbol]S[/symbol];T4Sun4[symbol]p[/symbol];r2Sun[symbol]p[/symbol];r2Earth/4[symbol]p[/symbol];D2Earth)(1-AEarth = [symbol]S[/symbol];T4Earth4[symbol]p[/symbol];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.

19

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

20

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