Over the past twenty years, vested interests and political lobby groups have done a fantastic job confusing the public about anthropogenic climate change. To many, they seem to have proven the whole theory wrong.
But how could you actually prove global warming wrong – not just in the minds of the public, but through the established scientific process? What scientific discoveries – if they held up through peer-review, further criticism, and replication – would render climate change a non-problem?
One of the surest ways to stop all this cap-and-trade discussion would be to disprove the greenhouse effect itself – the mechanism by which the Earth absorbs and emits the same energy multiple times, due to the presence of greenhouse gas molecules that “bounce it back”. This keeps the Earth substantially warmer than it would be otherwise. Additionally, if the concentrations of greenhouse gases increase, so will the temperature of the Earth. This process was first hypothesized by Joseph Fourier in 1824, and was experimentally confirmed by John Tyndall in 1856. The first prediction of eventual man-made global warming came from Svante Arrhenius, in 1896. It wasn’t a theory as much as a logical result of a theory, one that was deeply rooted in physics and chemistry.
Unless our understanding of entire fields of physical science is totally off base, we can be sure that our greenhouse gas emissions will cause climate change eventually. But hey, if you could overturn all of thermodynamics, you wouldn’t have to worry about carbon taxes.
- Cheap-out option: Svante Arrhenius was Swedish, but his name sounds sort of Russian, and 1896 wasn’t very long before the Russian Revolution. Therefore, Arrhenius was a Communist, and none of his scientific work can be trusted.
Knowing that something is sure to happen eventually, though, is different from knowing that it is happening right now with substantial speed. We know that the Earth is warming – even if you found some statistical way to disprove three separate temperature records, the physical and biological systems of our planet still stand: 90% of observed changes in the natural world, like the blooming of flowers, the peak flows of rivers, and the spawning of fish, are in the direction expected with warming (Rosenzweig et al, 2008).
But how do we know that the warming is caused by us? Climate change has been caused many times in the past by factors unrelated to greenhouse gases – like solar influences, whether they’re direct (a change in solar output) or indirect (a change in the Earth’s orbit). How do we know that’s not happening now?
If the warming was caused by the sun, the atmosphere would warm uniformly at all levels. However, if the Earth was warming from greenhouse gases, the troposphere (the layer of the atmosphere closest to the planet) would warm while the stratosphere (the next level up) would cool. This is because more heat is getting bounced back to the surface by greenhouse gases, and is subsequently prevented from reaching the stratosphere.
A cooling stratosphere has been described as the “fingerprint” evidence of greenhouse-induced warming. And, in fact, the stratosphere has been cooling over the past 30 years (Randel et al, 2009). Therefore, if you could somehow show that something else was causing this pattern of a warming troposphere and a cooling stratosphere, and that the significant, anthropogenic rise in greenhouse gases was somehow not affecting it, you would have a case for global warming being natural.
Update (18/2/10): About half of this cooling can be attributed to ozone depletion, and the other half can be attributed to greenhouse gases (NOAA, 2006). The flat trend in stratospheric temperatures from 1995-2005 (see the Randel citation above) can be explained by the recovery of ozone, which is temporarily offsetting the greenhouse gases. Interesting how the temperature of the stratosphere has just as many factors as the temperature of the troposphere…..but in both cases, you can’t explain the temperature trends without including human activity. Scott Mandia has a great explanation here.
- Cheap-out option: Omit the explanation of why greenhouse warming causes stratospheric cooling. Just point to the graph that goes down and say, “The atmosphere is cooling! Therefore, the IPCC is a hoax!”
Finally, even if you couldn’t disprove that global warming is expected, observed, and anthropogenic, you could still show that it isn’t very significant. The way to do this would be to show that climate sensitivity is less than 2 C. Climate sensitivity refers to the amount of warming that would result from a doubling of carbon dioxide equivalent, and 2 C is generally accepted as the maximum amount of warming that our society could endure without too much trouble. The current estimates for climate sensitivity, in contrast, average around 3 C (a range of 2-4.5), and it is very unlikely to be less than 1.5 C (IPCC AR4).
However, a climate sensitivity of less than 2 C only means that climate change isn’t a problem if our greenhouse gases stop at a doubling of carbon dioxide equivalent from pre-industrial levels. Even without taking methane and other greenhouse gases into account, this brings us to a CO2 concentration of 560 ppm, which we are well on track to surpass, even with cap-and-trade. So you’d have to argue for a climate sensitivity of even less. Seeing as we’ve already warmed 0.8 C, it doesn’t leave you with a lot of wiggle room.
- Cheap-out option: Build a climate model that does what you want it to, without any regard for the laws of physics. ExxonMobil will probably sponsor the supercomputers. Widely publicize the results and avoid peer-review at all costs.
Daunting tasks, certainly. But if you really believe that global warming is natural/nonexistent/a global conspiracy, this is the way to prove it. If you managed to prove it, and change the collective mind of the scientific community (not just the public), you’d probably win a Nobel Prize. So it’s certainly worth your time and effort.
ClimateSight 
I think that your “cheap-out options” detract from a very good post
[Everyone has their own sense of humour. I think that it’s healthier to laugh at the ridiculousness of these PR games than it is to fully let in how damaging they could be to the well-being of our society. -Kate]
Kate,
It is estimated that about 50% of the cooling of the stratosphere is attributed to ozone loss (Avajon, et al. 2007). I describe this here but I am still not convinced what I wrote makes sense to the average person. Does it make sense to you?
Ajavon, et al. (2007, February). Scientific assessment of ozone depletion: 2006. Retrieved from National Oceanic and Atmospheric Administration Earth System Research Laboratory Chemical Sciences Division Web site: http://www.esrl.noaa.gov/csd/assessments/2006/report.html
[That’s very interesting. It’s never as simple as just one factor involved, but even when you take into account all the factors….you still see our influence. -Kate]
“Arrhenius was a Communist, and none of his scientific work can be trusted.”
Lol, but alas, no, this cannot be. Arrhenius is a Viking name, and the plot is to force everyone to warm the globe so Vikings could resettle Antarctic. Henry Ford, with his T-model (temperature-model!) was also a part of this plot ;-).
Great post Kate! Perfect timing.
Skeptics don’t have to prove a theory wrong, it is for others to propose a theory for testing.
[citations needed – stratosphere is not cooling]
Actually, Arrhenius was a supporter of racial theories (eugenics); unfortunately common at the time in Sweden among many intelligentsia.
…forgot to add: this shows that you can be an asshole and a damn good scientist at the same time.
…and eh, that’s five different temperature records (don’t forget the satellites!) and the tide gauges.
[Where can I find the satellite data? -Kate]
Kate you haven’t come across the satellite data yet? You’ve got UAH, collated by Spencer and Christy, and RSS (remote sensing systems) which is an independent analysis.
All temp metrics can be graphed at woodfortrees: http://www.woodfortrees.org/plot/
UAH txt data can be found here: http://vortex.nsstc.uah.edu/data/msu/t2lt/uahncdc.lt
I haven’t browsed RSS as much but I think you’d find what you need here: http://www.ssmi.com/msu/msu_data_description.html
Hope this helps
Excellent post.
Here is a brand new report of the changes in the biological system, where one of the point they make is that spring in UK arrives on average 11 days earlier in 2005 compared to 1976:
http://www3.interscience.wiley.com/cgi-bin/fulltext/123233053/PDFSTART?CRETRY=1&SRETRY=0
Here is a News report about the research:
http://planetearth.nerc.ac.uk/news/story.aspx?id=661
[Do you have a different link to that study? I don’t have a login for Wiley, and it doesn’t look like Global Change Biology has its own webpage. -Kate]
[citations needed – CO2 warming is permanent and misunderstood as temporary]
[citations needed re: hotspot. Direct links to published papers please!]
The ‘hotspot’ that he (Christy) talks about is the ‘fingerprint’ that the CO2 is supposed to show in the troposphere. The words are interchangeable.
1)The IPCC graph was model runs to show each agent. You would have to look at the Chapter 9 graph to see those results. The IPCC is peer-reviewed. The paper that they cite for the graph (p. 675) is Ben Santer:
Santer et al. 2003
Santer, B.D., R. Sausen, T.M.L. Wigley, J.S. Boyle, K. AchutaRao, C. Doutriaux, J.E. Hansen, G.A. Meehl, E. Roeckner, R. Ruedy, G. Schmidt, and K.E. Taylor, 2003: Behavior of tropopause height and atmospheric temperature in models, reanalyses, and observations: Decadal changes. J. Geophys. Res., 108, no. D1, 4002, doi:10.1029/2002JD002258.
Click to access 2003_Santer_etal.pdf
From the abstract, last line:
The graph of the “fingerprint” is here, from the IPCC.
2)The Climate.gov site is peer-reviewed as well. One of the Lead Authors is James Hansen of NASA. The radiosonde data (p. 28) was estimated from this work:
Thorne et al. 2005
Thorne, P.W., T.R. Karl, H. Coleman, C.K. Folland, B. Murray, D.E. Parker, V. Ramazwamy, W. Rossow, A.A. Scaife, and S.F.B. Tett, 2005: Vertical profiles of temperature trends. Bull. Amer. Meteorol. Soc., 86, 1471-1476, doi:10.1175/BAMS-86-10-1471.
Click to access 2005_Thorne_etal.pdf
You asked for another explanation of the “fingerprint”, and Christy has one at his blog. You can read about it here.
Kate,
The fingerprint is not the cooling of the stratosphere, it is the warming of the troposphere between 8km and 12km The fingerprint is supposed to be the CO2 caused warming in that region. Hence, the fingerprint. They came to this conclusion by using models to see what the different forcing, absent of all others, and where. You can see the results in figure 9.1 here. The results from (c) are all GHG forcings, and (f) is all forcings combined. Source of that graph is:
Santer et al. 2003
Santer, B.D., R. Sausen, T.M.L. Wigley, J.S. Boyle, K. AchutaRao, C. Doutriaux, J.E. Hansen, G.A. Meehl, E. Roeckner, R. Ruedy, G. Schmidt, and K.E. Taylor, 2003: Behavior of tropopause height and atmospheric temperature in models, reanalyses, and observations: Decadal changes. J. Geophys. Res., 108, no. D1, 4002, doi:10.1029/2002JD002258.
Click to access 2003_Santer_etal.pdf
The only problem is that the fingerprint is not found in the data. If one looks at Temperature Trends in the Lower Atmosphere – Understanding and Recognizing Differences, p. 116, you can see that that fingerprint is not there according to HadAT2 radiosonde data (E). Source of that graph is:
Thorne et al. 2005
Thorne, P.W., T.R. Karl, H. Coleman, C.K. Folland, B. Murray, D.E. Parker, V. Ramazwamy, W. Rossow, A.A. Scaife, and S.F.B. Tett, 2005: Vertical profiles of temperature trends. Bull. Amer. Meteorol. Soc., 86, 1471-1476, doi:10.1175/BAMS-86-10-1471.
Click to access 2005_Thorne_etal.pdf
The data for the troposphere is here at UAH, and here at RSS.
[I don’t see where you’re getting the idea that the hotspot is a definitive fingerprint of greenhouse warming. Models predict a very similar hotspot for solar-induced warming (from a GISS equilibrium model). It looks like it has to do with warming in general, not just with greenhouse warming.
Also see the Wigley et al report that says, “This difference between models and observations may arise from errors that are common to all models, from errors in the observational data sets [more likely], or from a combination of these factors.”
Also, keep in mind that the hotspot is not absent in all datasets – see this list of citations.
A result common to most model simulations is very different to something that we understand theoretically – like why greenhouse gases cause cooling in the stratosphere, and a faster rate of warming over nights than over days. Those are fingerprints unique to greenhouse warming – a hotspot is not (yet – like Santer says, it could become more useful in the future when we understand it better). -Kate]
Huh? I linked the paper directly as well as giving its name.
[It hasn’t been published anywhere, though. -Kate]
> [Where can I find the satellite data? -Kate]
The easiest way to play with it is through this site.
…the data sources are given here. Note that the satellite measurement is of the lower troposphere, which is not precisely the same as what the surface stations measure.
Re: [Do you have a different link to that study? I don’t have a login for Wiley, and it doesn’t look like Global Change Biology has its own webpage. -Kate]
I’m sorry, can´t find it anywhere else – it will propably pop up on google scholars after some weeks or months-maybe.
Maybe you have access to this – the abstract: http://www3.interscience.wiley.com/journal/123233053/abstract
Shorter denialism:
Only theories I dislike should be tested, theories I like should get a free pass.
[inflammatory]
Scott Mandia, I have a hard time believing that Roger Pielke Sr isn’t aware of the ozone factor when he says that there needs to be an explanation for why the stratosphere is not cooling.
MikeN:
Martin Vermeer:
Indeed, Martin Vermeer. Interesting that cranks somehow manage to interpret the idea that ‘the burden of proof lies in the prover’ as a blanket excuse to do zero fact-checking.
[citations needed – CRU emails show a conspiracy, Arctic ice is recovering, temperature has been flat for 15 years, Antarctic ice is near record levels, the sea level has not risen, CO2 is plant food]
MikeN,
The stratosphere IS cooling. The lower stratosphere has not warmed recently because the cooling due to increased GHGs has been offset by increasing ozone which warms that region. The stratosphere as a whole is still cooling.
Do you have a link to where Dr. Pielke, Sr. makes the claim that there is not cooling? Perhaps he is just speaking about the lower stratosphere?
An interesting aspect of this is that the skeptics haven’t put together their own reconstructions. They feel that they can discredit scientists who have done their own reconstructions, but until they put something out there that is robust enough, they will be considered to be just rabble-rousers.
http://pielkeclimatesci.wordpress.com/
Scroll down to where he discusses Solomon’s paper.
Indeed he is saying lower stratospheric cooling is flat since 1995, inconsistent with models, and needs to be explained.
MikeN: Don’t you think the better question then is:
If ozone is actually increasing, then why isn’t there a warming trend in the lower stratosphere?
Perhaps, as has been suggested, the warming from increased ozone has been offset by the cooling due to increasing GHGs. Henece a flat trend instead of a rising trend.
Dr. Pielke cannot be serious if he thinks that if one aspect of climate model prediciton is not accurate then it throws suspicion on all other predicitve aspects.
Since you deleted my discussion, can you state what point or points would have to be made to prove AGW wrong?
Thanks.
[Erm, read the article. -Kate]
Here’s my take on how to ‘easily’ falsify the ‘AGW hypthesis’: http://ourchangingclimate.wordpress.com/2010/01/06/a-quick-n-dirty-guide-to-falsifying-agw/
along the same lines as how one could falsify the ‘gravity hypothesis’ by pointing out that that bird up there in the sky proves it wrong.
[That’s a great analogy. When I give presentations, I’m usually speaking to high school students, so a similar analogy I like to use is the formula F=ma (drilled into the heads of every high school physics student fairly quickly), where, to find the net acceleration, you must always use the net force. Similarly, you cannot analyse or attribute changes in global temperature by only taking one radiative forcing into account. There’s more than one factor involved. -Kate]
I’d just like to point out a minor error in an otherwise quite satisfying post. In your third paragraph, you allude to the physics and/or chemistry of the greenhouse effect being “subatomic”. Nothing in 1896 was subatomic. One might call the absorption and transmission of light by various atmospheric gases a subatomic phenomenon, but it would be a big stretch. Chemical (electrical) bonds between atoms are the primary effect, and as rule that’s not really classified as ‘subatomic physics’….
…which is all just to say that if you delete the word ‘subatomic’, I’m all happy again.
[Thanks for the correction, I just changed it. -Kate]
“One of the surest ways to stop all this cap-and-trade discussion would be to disprove the greenhouse effect itself.”
I’m always completely amazed at some people’s ability to believe they’ve found the fatal flaw/”smoking gun” (how many of those have we had?) in climate science. Have you seen this one ‘disproving’ the greenhouse effect?
http://www.countingcats.com/?p=4745
Lauded by –
http://www.devilskitchen.me.uk/2009/10/greenhouse-effect.html
The mistakes are pretty easy to spot, but it all sounds terribly plausible. XKCD nails this kind of mentality perfectly – oh, actually, googling for it, I found it on your site!
http://xkcd.com/675/
Here’s me waffling about the same if you’re interested.
http://www.coveredinbees.org/node/266
@Dan Olner – you say the mistakes are easy to spot’ – but things are only ever easy when you know how to do them. The trouble with the kind of meme that you’re pointing at is that if it’s believable, it risks gaining ground. Do you have an ‘easy’ refutation?
I wish people would stop asserting Fourier had ANYTHING to do with the “greenhouse effect” nonsense. Here is a quote :-
“In short, if all the strata of air of which the atmosphere is formed, preserved their density with their transparency, and lost only the mobility which is peculiar to them, this mass of air, thus become solid, on being exposed to the rays of the sun, would produce an effect the same in kind with that we have just described. The heat, coming in the state of light to the solid earth, would lose all at once, and almost entirely, its power of passing through transparent solids: it would accumulate in the lower strata of the atmosphere, which would thus acquire very high temperatures. We should observe at the same time a diminution of the degree of acquired heat, as we go from the surface of the earth.”
Now to me that sounds like the complete reverse – only a fool would believe the atmosphere could work as described in the above passage.
During the day the Sun can heat the Earth’s surfaces to very high temperatures while the ambient air temperature is much cooler – walk on asphalt exposed to sunlight in the middle of the day to confirm this.
Idiots say the warmth you feel coming from the asphalt is radiation while it is clearly warmed air convecting up from the very hot surface.
Idiots also miss the inescapable reality that the atmosphere actually cools the Earth’s surface during the day – AND – as this is an argument about radiative heating during the day is all that matters.
“Climate scientists” dismiss the power of the Sun to heat the Earth above minus 18 degrees C but this simply denies reality where experiments prove that the Sun’s radiation can heat surfaces on Earth to much higher temperatures than the atmosphere EVER reaches.
Call me old fashioned but I still believe “heat” doesn’t travel from cold sources to hotter receivers – I think simple logic says that is not true let alone physics.