January 17, 2013, by Tim Radford
FOR IMMEDIATE RELEASE Two US government bodies have given their backing to a finding by British scientists which some observers interpret as evidence that global warming is slowing significantly. LONDON, 17 January – US scientists have now formally confirmed a judgment by the UK Met Office just before Christmas, posted on 24 December: that 2012 was the ninth warmest year on record, and that 11 of the 12 warmest years in history have fallen in this century. The US announcement came from the Goddard Institute for Space Studies, the Nasa laboratory which monitors global surface temperatures and then compares them with a long-term average. The differences are slight but the trend is unmistakeable. “One more year of numbers isn’t in itself significant,” said Gavin Schmidt of Goddard. “What matters is this decade is warmer than the last decade and that decade was warmer than the decade before. The planet is warming. “The reason it’s warming is because we are pumping increasing amounts of carbon dioxide into the atmosphere.”
“The climate dice are now loaded.”
The US global temperature record goes back to 1880, when the carbon dioxide level in the atmosphere was 285 parts per million (ppm). By 1960, the concentration measured at the observatory on Mauna Loa in Hawaii was 315 ppm. It is now more than 390 ppm. The three hottest years ever recorded are 2010, 2005 and 1998, according to the UK’s Met Office Hadley Centre, a finding now confirmed by scientists both at Nasa and at the US National Oceanic and Atmospheric Administration. All three agencies use slightly different methods and a slightly different baseline of comparison, but all tell the same story. Earlier in January, some media reports suggested that the UK Met Office foresaw a period of cooling, or perhaps even the end of global warming: in its 24 December statement it said: “…global temperatures over the next five years are likely to be a little lower than predicted… in December 2011″. But the officially released figures should settle the confusion. “The climate dice are now loaded,” said James Hansen, head of the Goddard Institute. “Some seasons still will be cooler than the long-term average, but the perceptive person should notice that the frequency of unusually warm extremes is increasing. It is the extremes that have the most impact on people and other life on the planet.” – Climate News Network
Tim Radford, a founding editor of Climate News Network, worked for The Guardian for 32 years, for most of that time as science editor. He has been covering climate change since 1988.