Other posters have already said most of what I would say in response to the OP, but just to summarize:
(1) The link is correct in its claim about the strength of the natural greenhouse effect.
(2) The link is incorrect about the relative strengths of the contribution to this natural effect from water and CO2. I think the correct numbers are those that Malodorous gave from the Wikipedia article…i.e., that it is responsible for 9-24% (the numbers I remembered were 10-30%, but that is roughly the same).
(3) As SentientMeat pointed out, there is also the issue that because of its abundance on the planet and its short residence time in the atmosphere, water concentration is essentially “slave” to the temperature. So, if you warm the world by adding more CO2, that will cause the average amount of water vapor in the atmosphere to increase too, which because water is a greenhouse gas then leads to more warming…i.e., a positive feedback that is estimated to approximately double the effect due to the increase in CO2 alone.
(4) CO2 concentrations in the atmosphere have indeed increased by ~35% (from ~280ppm to ~380ppm) since the start of the industrial revolution (with more than half of that increase having occurred since 1970), to levels far higher than they have been through something like the last 7 ice age - interglacial cycles going back ~700,000 years (over which we have very accurate measurements from ice cores) and likely the highest for millions of years. My guess is that the link derived the incorrect 3.2% figure by looking at the ratio of the total amount of emissions in a year due to humans vs that due to natural processes. The problem with this logic is the natural processes are exchanges…i.e., the oceans, land, and biosphere emit lots of CO2 each year but also absorb lots of CO2 each year. Before the industrial revolution, these processes were essentially in balance so the concentration of CO2 was quite steady around 260-280ppm since the end of the last ice age. Our emissions have caused it to go out-of-balance. [An analogy might be to a bathtub with an open drain where I carefully adjust the faucet so that the water is coming in at the same rate as it is going out the drain so the level is constant right near the top of the tub. Then, if you came along and started dumping more water in and the tub started overflowing, you might try to argue it is not your fault since the amount of water you are putting in is not as much as the amount coming out of the faucet. Of course, this analogy is not perfect because, for example, in the real world we can’t adjust “the faucet”…In fact, it might be a better analogy if the faucet was being supplied by a pump that just pumped back up all the water that went out the drain.]
By the way, something I meant to add to my point (2) is that the reason that the range of values is so large on the amount that CO2 contributes to the natural greenhouse effect is that the effects of the different contributors to the greenhouse effect are non-additive because of their overlapping spectra.
So, for example, if you start with the current atmosphere and subtract out the CO2 while keeping all the other greenhouse gases constant then you get the greenhouse effect reduced by ~9% (although, for reasons noted above, this is not a completely realistic experiment since if you took out the CO2 and temperatures fell, then the amount of water vapor in the atmosphere would drop too causing additional cooling). However, if you start with the atmosphere empty of all greenhouse gases and add the current value of CO2, you would get ~24% of the total greenhouse effect that we see. [See here and here for more discussion.]
I agree with you that Landsea is a respected researcher. However, on this whole quitting of the IPCC process, I also think he was a bit of a hot-head. Basically, he quit because he was upset that Kevin Trenberth, the lead author of one of the chapters (in fact the chapter that Landea had been asked to contribute to), participated in a press conference in which he made statements regarding global warming and hurricane activity that Landsea thought were wrong and outside the mainstream and that it was also mentioned that Trenberth was a lead author on the IPCC reports. Landsea essentially demanded that the IPCC replace Trenberth as the lead author on that chapter and issue some sort of statement repudiating Trenberth’s remarks as not representing the views of the IPCC.
The IPCC basically pointed out that they do not police the statements made by researchers who are participating in their reports and that researchers noting that they are “lead authors” in the IPCC reports as part of their qualifications does not imply that all of the views they express are those of the IPCC. And, in fact, if you look on the web, you will find that Richard Lindzen, arguably the most pre-eminent AGW skeptic, often writes pieces (such as op-eds in the Wall Street Journal) where it is noted that he was a lead author on past IPCC reports and I think most scientists would say that in these pieces he says things that are far outside the scientific mainstream but, to my knowledge, the IPCC has never decided to issue statements repudiating him or asked him to stop noting he was a lead author.
It is also worth noting that the field regarding observations in changes in tropical cyclone activity (particularly intensity) has been undergoing rapid change, so while Trenberth’s statements arguably may have been outside the mainstream on the basis of the last IPCC report in 2001, they are now supported by a number of papers (although I would say that the opposing viewpoint that Landsea holds is also still within the mainstream in this particular area that remains in a state of flux).
By the way, if you look at the summary for policymakers of the new IPCC report, here is everything it has to say about tropical cyclones:
And, in their chart of phenomena and trends, they rate the statement that “Intensity of tropical cyclone activity increases” as “likely” (>66% chance) to have occurred in some regions since 1970, “more likely than not” (>50% chance) that there was a human contribution to this trend, and “likely” to occur during the 21st century based on projections.
A final point is that I agree with you that no particular weather event can be definitively attributed to global warming. What can be said, however, is that it is making certain events more likely. So, if the anthropogenic contribution to hurricane intensity trends turns out to be real, the sort of analogy that is often made is to rolling a die that has been weighted so it has, say, twice the normal chance of rolling a six. Then, any particular time that you role a six, you cannot conclude for sure that this is the result of having weighted the die…However, the long term, you will see a six roled about twice as many times as you would have had you not weighted the die.
I have heard that scientists were threatened for not having the same conclusion as other scientists and that the government payed for studies with predetermined outcomes and excluded scientists who didn’t have the conclusion the government demanded.
Well, I am not sure which government you are talking about. What is known is that an aide in the Bush Administration, Philip Cooney with no scientific training was editting reports from the EPA to change how the science was being presented. The editting was so bad in a report on the general state of the environment (and the EPA was apparently told that the edits were essentially mandatory) that the EPA made the decision to just eliminate the chapter on climate change entirely from the report rather than to go with the scientifically-indefensible version that Cooney had come up with. Cooney worked for the American Petroleum Institute before coming to the White House and, after this furor about his editting of the report erupted, he resigned and took a job with Exxon-Mobil.
In principle, global warming could be debunked like any other scientific hypothesis or theory. However, I’m pretty sure the truth and the light isn’t going to be heralded by a one page article by Andew Swallow. It would probably involve some new discoveries, technologies, methods, and a bunch of those scientific type folk.
Here is what Heidi Cullen said, which sparked this particular fire:
I can see how some might see this as a “threat” to GW skeptics, but I disagree with that characterization.
Firstly - we’re talking about the view of one person (Cullen). The American Meteorological Society has said that they do not completely agree with Cullen’s stance on this. I think this is an important distinction that needs to be made.
Secondly - I don’t think that Cullen is saying these meteorologists should be stripped of their certification simply because they oppose the climate change science. It sounds like she has a particular problem with scientists who make outlandish claims against the evidence of climate change, without backing their claims up with any evidence of their own.
Imagine that you had a civil engineer who had his (or her) Professional Engineer (PE) license. And this engineer started making public statements against the widely accepted views of the effects of gravity. While I don’t think that this engineer should be stripped of his license (there may be some validity to his claims), I would definitely think twice before contracting him to design my next bridge.
LilShieste
It’s not like scientists have this central agenda that they’re trying to push onto everyone. (“That person doesn’t fall in line with our plan - they must be silenced!”) If evidence starts to indicate that we (humans) actually aren’t contributing that much to global warming, then scientists would be very interested in evaluating it and modifying their current models to accommodate it. They have absolutely no reason to disregard cold, hard evidence.
LilShieste
In addition to the point that LilShieste made, it is worth pointing out that she was directing the comment in regards to TV meteorologists, not active researchers in the field of climate change. [is the full context of Heidi Cullen’s remarks and here is a more extended statement from it:
And, while I admit that there is a legitimate debate about whether her idea is a good one or not, her point is that the AMS seal of approval is supposed to mean something in terms of qualifications and imply that this person has certain qualifications to talk about meteorology and should demonstrate some knowledge of various topics. And, of course, this is just one meteorologist’s opinion on what the AMS should do…It is not as if she even holds any position of authority that I know of within the AMS organization.
And, by the way, even this supposed “pressure” is not really directed at active researchers in the field of climate science. It is directed at people with some meteorological training but not actively working in the field who are making all sorts of statements regarding the science that most scientists in the field believe are incorrect, misleading, or discredited arguments.
When Richard Lindzen makes his “iris hypothesis” in the peer-reviewed literature or Svensmark publishes his work on cosmic rays, scientists may not embrace it as the most brilliant work since Einstein but they do not call for it to be suppressed. They go about testing it, or pointing out the ways in which they think it is incorrect, or whatever. And, Lindzen has served as both a lead author for the IPCC and as a member of a National Academy of Sciences (NAS) panel convened to answer questions from the Bush Administration on global warming…so it is indeed a bit strange when he argues how skeptics like him are suppressed. The NAS seemed to pretty much go out of its way to ask the most scientifically-respectable skeptic to be a part of its panel.
Look, there is no doubt that once any theory becomes the dominant “paradigm” in the field, data or hypotheses in contradiction to it will be treated with some skepticism. However, if the evidence is truly compelling and survives tests, the field will be won over after a while. To demand instant acceptance is not realistic as it would mean that theories would never be accepted in science at all because there is always some things that are a puzzle within the current theory. And, indeed, I think history of science shows that in most cases once a theory is well-established, evidence such as this is usually resolved in favor of the prevailing theory…or at most with a small tweak in its understanding. It is the exceptional case when such evidence really leads to a complete overthrow of the prevailing theory.
And, it is important to recognize that the theory of AGW itself took a long time to gain acceptance in the scientific community. (See [url=http://www.aip.org/history/climate/]here](]Here[/url) for a good history of the subject.) Arrhenius did the first calculation estimating how a doubling of CO2 concentration due to fossil fuel burning would change the global temperature about a century ago! However, for a variety of reasons, it took a long time before the idea won over the scientific community. (One reason being that it was not at all clear to scientists that we could change the concentration of CO2 through our emissions as many thought the oceans would just absorb all the CO2 we emitted and it wasn’t until the late 1950s that accurate measurements of CO2 levels in the atmosphere showed that it was indeed steadily increasing.) It is only with the mounting of more and more evidence that it became more and more clear to the scientific community that the theory is correct.
I wonder how accurate comparisons between current tropical storm/hurricane frequency and intensity and those of prior years (i.e. earlier in the satellite era) are. Has our ability to detect minimal tropical storms (like the one that got added to our '06 storm totals well after the season was over, lessening the impact of an overhyped forecast) improved?
I also notice some tendency in the media and among nonprofessional pundits to equate hot spells in particular areas for relatively short periods as evidence of global warming, which is just as irresponsible as trumpeting cold spells as debunking global warming. Fortunately climate experts are not prone to these kinds of distortions.
*What a great name for a hurricane expert.
Just out of curiosity, in general theories aren’t ‘debunked’…are they? They are superceded by either better theories or refinements on the existing theory. Correct?
Assuming I have that right…IS there an alternative theory to AGW/GW? Is that theory testable? All I ever hear is attempts to poke holes in AGW/GW…never a competing theory that attempts to explain whats going on.
But it wasn’t ‘debunked’…it was merely found to be wrong and superceded. Correct? (on Dictionary.com the def is: To expose or ridicule the falseness, sham, or exaggerated claims of: debunk a supposed miracle drug.)
No, for that you’d have to consider something like what happened with Pons-Fleishman’s cold fusion. Concensus is now pretty firm around that being pure bunkum.
Agreed…thats exactly the right example. GW however doesn’t fall anywhere close to that category. It may prove to be wrong ( :dubious: )…but it won’t be ‘debunked’.
Yes, the accuracy and consistency of the data over these years is what most of the debate is about and there is at least one project out there to try to re-analyze the previous years (post-satellite-era) with modern techniques to try to make sure consistent estimates of intensity were made.
In regards to your specific concern though: Remember that the significant trend that has been found is not in total numbers of hurricanes but in the number and strength of the highest intensity storms…so your hypothesis about the detection of minimal ones wouldn’t be relevant there.
Well, that’s a good question. I guess the major one of late seems to be that cosmic rays, presumably having their intensity modulated by the sun, affect cloud formation (by creating nucleation sites for water vapor to condense). There was recently a check on the basic mechanism in a lab experiment that was suggestive that under certain controlled circumstances, cosmic rays could form small potential nuclei. However, there are various problems with the theory…One being that measurements are being made of cosmic ray intensity and there doesn’t seem to have been any significant trend to explain the recent warming (although proponents say that maybe the wrong energies are being measured). There have also been attempts to analyze satellite photographs of cloud cover to detect trends in that which haven’t really panned out (and proponents have then suggested one has to focus on low clouds specifically). See this RealClimate piece and references therein for more discussion.