When it comes to getting scientifically reputable information on climate change, it can be a daunting task because of the politicization that has surrounded this issue. No arguments there. However, on October 16th, when Charles Adler heard about an article published in the Daily Mail in the UK with the extraordinary title “Global warming stopped 16 years ago, reveals Met Office report quietly released… and here is the chart to prove it”, he invited Tom Harris to his talk-show to help inform Canadians what the article was all about. (You can listen to the podcast of the segment here.) What followed was several questionable claims including the claim, accepted with no critical analysis, that the earth has not warmed in 16 years.
Tom Harris, a person well known for not getting the science of climate change right, is not a reputable source of climate change information for a nationally syndicated radio talk show. This was attested to by the authors of a report by the Committee for the Advancement of Scientific Skepticism regarding Tom Harris’ course that he taught at Carleton University. The report details over a hundred instances of his course incorrectly describing our current and best understanding of the earth’s climate.
During the radio show, Tom Harris and Charles Adler lamented about why the main stream media had not picked up this story. The simple reason for this exclusion on behalf of the major news networks could be because the MET office at the University of East Anglia has never stated that “global warming stopped 16 years ago” as the original Daily Mail article claims. The MET staff attempted to clarify this on their blog shortly after the Daily Mail article came out. The spark that started this little fire happened when David Rose, the author of the Daily Mail article, downloaded the latest update of the HadCRUT4 surface temperature data set from the MET Office. Based on this data, he appears to have drawn his own conclusions out of context. You can read the MET Office’s blog response to the article here. In the blog, the MET Office explains why David Rose should not have concluded that global warming has stopped. Regarding, the last 16 years of surface temperature data, the earth’s surface has continued to warm but at a reduced rate.
“Over the last 140 years global surface temperatures have risen by about 0.8ºC. However, within this record there have been several periods lasting a decade or more during which temperatures have risen very slowly or cooled. The current period of reduced warming is not unprecedented and 15 year long periods are not unusual.”
The surprising thing about the earth’s surface temperature is that it can go down while the planet is warming and the surface temperature can go up while the planet is cooling. This is largely because of the heat that is sloshing around our planet’s oceans. This discrepancy between the earth’s warming and the earth’s surface temperature can be illustrated with the following example. Imagine you want to heat up your cold bath water. A tea cup full of water at 100°C (high temperature) is not as useful for warming up the cold bath as a bucket full of water at 50°C (medium temperature). The bucket of water at the medium temperate contains more heat than the teacup of water at 100°C. Similarly, the primary explanation for the surface temperatures not correlating with the earth’s warming, or cooling, as one might expect is the oceans’ mass and the oceans’ ability to hold heat. The amount of heat in the oceans is not necessarily reflected in temperature of the oceans’ surface. However, over long time scales you would expect the increasing heat content of the oceans to affect the earth’s surface temperature a noticable amount.
The following graphic from the MET Office shows surface temperature data over longer time scales. It highlights the warmest years and the decade to which they belong. Eight of the warmest years on record have occurred over the last ten years. Note that 2011 did not make the top ten but 1998 did. By examining the data you can observe that this sort of anomaly is not unusual in the temperature record and furthermore it is hard to deny that it looks like the earth is continuing to warm.
In Ontario, where I teach physics, students learn about climate change as part of their grade 10 science course. Charles Adler’s talk show reaches Canadian students and their parents in many cities and some of the claims made on his radio show were not in agreement with what we know to be true of our planet’s complex climate system. To say global warming ceased more than a decade ago is not supported by the data, the scientific literature, or even by the actual temperature data set quoted in the Daily Mail article that started the whole unsubstantiated claim in the first place. When it comes to educating the Canadian public about climate change and other areas of scientific inquiry that have traction in the media, it would be great if talks shows like the Charles Adler show would consult experts representative of our best scientific understanding. That way, erroneous claims can get rooted out before hitting the airwaves.