After hyping an alleged “pause” in global warming, mainstream media have entirely ignored a groundbreaking study finding that warming over the last 16 years has actually proceeded at the same rate as it has since 1951 with no “pause” compared to that time period.
The study, published in the Quarterly Journal of the Royal Meteorological Society by Dr. Kevin Cowtan of the University of York and Robert Way of the University of Ottawa, found that the average global surface temperature has warmed 0.12 degrees Celsius between 1997 and 2012 (see the bold “Global” line in the graph above) -- two and a half times the UK Met Office's estimate of 0.05°C (see “Met Office” line). According to the new estimate, over the last 16 years the globe has warmed at the same rate as it has since 1951.
Writing about the study at the scientific blog Real Climate, climate scientist Stefan Rahmstorf concluded that the public debate about the “pause” has “become” completely baseless" and that any speed bump in warming is “not surprising” with natural variability:
The public debate about the alleged “warming pause” was misguided from the outset, because far too much was read into a cherry-picked short-term trend. Now this debate has become completely baseless, because the trend of the last 15 or 16 years is nothing unusual - even despite the record El Niño year at the beginning of the period. It is still a quarter less than the warming trend since 1980, which is 0.16 °C per decade. But that's not surprising when one starts with an extreme El Niño and ends with persistent La Niña conditions, and is also running through a particularly deep and prolonged solar minimum in the second half.
An earlier Media Matters analysis found that mainstream media mentioned the alleged “pause” in nearly half of coverage of a major international climate report by the Intergovernmental Panel on Climate Change (IPCC). However, media have often been reluctant to cover data contradicting that narrative, including a study finding that heat may have been stored in the intermediate depths of the ocean, where warming has proceeded 15 times faster than in the past 10,000 years, rather than in the atmosphere.
As for claims that global warming has “stopped” or that global warming is "[o]ver," the study found with 94 percent probability that there has been some warming over the last 16 years. Dr. Cowtan wrote that “the hypothesis that warming has accelerated ... is four times as likely as the hypothesis that warming has stopped.”
Why were previous estimates off?
The Met Office's data had several gaps (illustrated by white squares in the maps below) in areas, such as the Arctic, that have experienced some of the most rapid warming. Dr. Cowtan and Way found more significant warming when they filled in these gaps with satellite data:
Dr. Cowtan was quick to note that one study does not end the scientific discussion about the factors influencing recent warming, saying “No difficult scientific problem is ever solved in a single paper. I don't expect our paper to be the last word on this, but I hope we have advanced the discussion.” However, the new results fall within the uncertainty range of the Met Office's data, illustrating the problem with the media broadcasting conclusions from short-term data.
*According to Nexis and Factiva searchesfrom November 12 (when the study was published) to November 17, 2013. We searched Nexis for "(Kevin w/2 Cowtan) or (Robert w/2 Way) or Royal Meteorological Society or ((pause or slowdown or hiatus or 15 years or 16 years or 17 years or 1997) and (global warming or climate change))" for the Associated Press, Los Angeles Times, The New York Times, The Washington Post, USA TODAY, ABC, CBS, NBC, CNN, Fox News, and MSNBC. We similarly searched Factiva for "(Kevin near2 Cowtan) or (Robert near2 Way) or Royal Meteorological Society or ((pause or slowdown or hiatus or 15 years or 16 years or 17 years or 1997) and (global warming or climate change))" for The Wall Street Journal, Reuters and Bloomberg News.