It seems like we have to debunk this myth on a weekly basis, as it keeps popping up in the mainstream media. So, yet again, this is global warming:
Figure 1: Land, atmosphere, and ice heating (red), 0-700 meter ocean heat content (OHC) increase (light blue), 700-2,000 meter OHC increase (dark blue). From Nuccitelli et al. (2012).
The overall warming of the Earth over the past 15 years was larger than over the previous 15 years. Global warming has not stopped; it's not even slowed down.
A leading purveyor of the myth to the contrary is journalist David Rose, of the British tabloid The Mail on Sunday and Vanity Fair. We've previously pre-bunked and debunked his articles on the subject, but he appears oblivious to any criticism of his work.
"No, the world ISN'T getting warmer (as you may have noticed)," wrongly begins an article published in last week's Mail on Sunday. Try saying 'there's no noticeable warming' to the Australians and Americans who suffered the greatest run of heat waves ever recorded; or the British or New Yorkers who were flooded out of their homes during 2012.
Rose's latest denial of global warming makes a great play of this graphic created by Ed Hawkins of the University of Reading (which Rose modified, printed, and misrepresented without permission or attribution). [Update 2. 19:41 GMT, March 20th: The Mail has now attributed the figure to Ed Hawkins' site, provided a link and apologised. However they still misrepresent Ed Hawkins' original graphic.]
Figure 2: Comparison of observed global surface temperature changes (black) with 38 climate models in the Coupled Model Intercomparison Project Phase 5 (CMIP5), including 25–75% and 5-95% uncertainty ranges (gray).
Rose's first mistake is to claim that "the speed of global warming has been massively overestimated." Putting aside the fact that he's only looking at surface air temperatures, which only comprise a small percentage of global warming; as Ed Hawkins noted,
"In the article David Rose suggests that this figure proves that the forecasts are wrong. This is incorrect ... the observations are at the lower edge of the projected range"
Despite being on the lower end of that range, global surface temperatures are nevertheless within the 90% (5–95%) confidence interval of model runs, and therefore have not been overestimated. Note that we expect the data to fall outside the 90% range 10% of the time, so even if the observational temperatures were outside that envelope (which they are not), it wouldn't necessarily mean that global surface warming has been overestimated. This is further illustrated by a simiar graphic created by Gavin Schmidt at RealClimate, using the previous Coupled Model Intercomparison Project collection of climate models, CMIP3, which shows that the observed surface temperatures are within the 95% model confidence interval (Figure 3), which is somewhat wider than the 90% confidence interval.
Figure 3: Annual mean global surface air temperature anomalies from the CMIP3 models plotted against the surface temperature records from the HadCRUT4, NCDC and GISTEMP products, baselined to 1980-1999 (as in the 2007 IPCC report). The envelope in grey encloses 95% of the model runs.
So why are surface temperatures currently on the lower end of that 90% interval? There may be several contributing factors, one being that there has been a preponderance of La Niña events over the past decade, which cause a short-term cooling of surface temperatures. Over this timeframe, more heat has accumulated in the deeper oceans — heat which David Rose conveniently ignores by focusing exclusively on surface air temperatures.
Rose's second error is contained in the article sub-heading, but he quickly contradicts it himself in the body of the article:
"No, the world ISN'T getting warmer ... there has been no statistically significant increase in the world’s average temperature since January 1997"
These two statements say very different things. Figure 1 obviously shows that the world IS getting warmer — in fact, over the past decade it has accumulated the equivalent heat of 4 Hiroshima atomic bomb detonations per second. But even surface temperatures have most likely warmed over that timeframe, at a rate of about 0.081 ± 0.13°C per decade. Calling that 'not warmer' is no different than saying 1 ± 2 = 0. It's just statistically and mathematically wrong. The surface warming trend may be zero; but it could also be +0.21°C per decade. Most likely surface temperatures have warmed 0.12°C since 1997, which is not zero.
Rose gathers some quotes from the few contrarian climate scientists who disagree with the 97% consensus that humans are causing global warming. Among these are Judith Curry and David Whitehouse, the latter being associated with the climate contrarian lobby group Global Warming Policy Foundation. Whitehouse is not a climate scientist.
Rose quotes Oxford's Myles Allen saying that the odds of catastrophic 5°C surface warming this century have come down, but that's a far, far cry from saying the planet isn't warming or that we shouldn't be worried about it, as Allen has explained in a response on The Guardian.
Rose also quotes Piers Forster as claiming that "global surface temperatures have not risen in 15 years." As shown above, this quote is factually wrong. Forster has also called Rose's article "terrible," and clarified his position on future warming:
"It's fine to say that current models overestimate the last decade of [surface] warming. They clearly do, and as I say in my quote I think we can rule out some high sensitivity values because of this. But to do a fair comparison you need to remove the effects of variability ... Even with a suggested ECS [equilibrium climate sensitivity] of around 2.5 C or so we can end up with a very significant climate change by 2100 if we don't do something—therefore I think the tone of the article in terms of its implications for the IPCC, climate science and the climate itself are all wrong ... I would put the best estimate using this evidence around 2.5 C."
In short, Forster believes the scientific evidence puts equilibrium climate sensitivity (the total amount of warming, including feedbacks, once the planet reaches a new energy equilibrium) in the 2–3.5°C range, most likely 2.5°C surface warming in response to a doubling of atmospheric CO2. This would mean a significant and potentially very dangerous amount of climate change over the next century if we listen to Rose and don't take serious action to address the problem.
Finally, Rose claims that James Annan believes that climate sensitivity is "likely to be about half of the IPCC prediction in its last report in 2007." This is a gross misrepresentation of Annan's views on the subject, which are very similar to Forster's, in that Annan thinks the higher end of the IPCC climate sensitivity range (above 4°C) is implausible and given too much weight.
The IPCC best estimate of equilibrium climate sensitivity is 3°C in response to a doubling of atmospheric CO2 (likely range of 2–4.5°C), while Annan believes the most likely value is about 2.5°C and unlikely above 4°C. Needless to say, 2.5 is quite a bit higher than half of 3, and is well within the IPCC likely range.
Annan has clarified his position on his blog, and expressed displeasure that Rose did not attempt to contact him before grossly misrepresenting his opinions.
"he never attempted to contact me to check he had represented my views accurately ... The bit Rose adds about "the true figure likely to be about half of the IPCC prediction in its last report in 2007" is a complete fabrication of course, it's not something I can imagine having said, or being likely ... their range, or best estimate, is certainly not something I would disagree with by a factor of 2."
In short, Allen, Forster, and Annan's positions are that we're not doomed to catastrophic climate change just yet. This is probably true, and is obviously very good news. But their positions also mean that continuing to rely on fossil fuels as Rose advocates will result in very dangerous and potentially catastrophic consequences. For Rose to claim these climate scientists' positions support his global warming denial is a gross distortion of their views, and it is not surprising that they have objected to these misrepresentations.
The second half of the article is ambiguous in that it appears to be written by — or is in the words of — David Bellamy, the botanist and former televison presenter. Here Bellamy is given a platform to complain he was kicked off TV due to his views on climate change, which contradicts a previous admisssion that his departure was because of his political activities.
However, leaving that aside, with Bellamy's input we end with a Gish Gallop of hackneyed climate myths. We'll not go into a detailed debunking in this post, but for the sake of thoroughness:
Rose and Bellamy also argue that the planet will survive global warming. While that is true, the question is whether species living on the planet will survive it, and how difficult that survival will become. The more and faster global warming and climate change humans cause, the more difficult it will be for species (including humans) to adapt to those changes, and the fewer species will surivive. As a botanist, we would have thought Bellamy should know this.
Ultimately David Rose has given us yet another textbook example of global warming denial, quite literally denying that the planet is warming. In attempting to support this myth, Rose has grossly misrepresented the positions of most of the climate scientists he references in his article, as well as misinterpreting their data.
In reality the planet is accumulating heat equivalent to 4 Hiroshima atomic bomb detonations per second, and that warming shows no signs of slowing, let alone stopping. It's a physical reality that the Earth will continue to accumulate heat as long as we continue to increase the greenhouse effect by adding CO2 to the atmosphere. Quite simply, global warming will not stop until we actually DO something to stop it. We cannot change the laws of physics simply by denying them.
Also see posts on this subject by Phil Plait at Bad Astronomy, Carbon Brief, and by the University of Reading's Richard Allan.
Posted by dana1981 on Tuesday, 19 March, 2013
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