January 21, 2015, by Tim Radford
Fire danger sign in Nevada, US, as temperatures soared last summer.
Image: Famartin via Wikimedia Commons
As statistics confirm that 2014 was the hottest year ever recorded, leading scientists say climate change trends are dominated by human emissions of greenhouse gases. LONDON, 21 January, 2014 − Last year was the warmest year on record, according to two separate analyses by two giant US government organisations. The findings, which confirm a conclusion that meteorologists confidently predicted last November, mean that 14 of the warmest years on record have happened this century, and nine of the 10 warmest years have been since 2000. Scientists from the space agency NASA and from the National Oceanic and Atmospheric Administration both examined surface temperature measurements around the planet and decided that 2014 was on average the hottest since 1880 − the earliest year for global records.
The post-millennial pattern was broken only in 1998 − the year of a super El Niño, when global warming coincided with the peak of a natural climate cycle in the Pacific. Not surprisingly, 2014 was also recently confirmed as the hottest year ever for the UK, where there have been sustained temperature measurements since 1659. And World Meteorological Organisation scientists warned last month that 2014 could be a record-breaking year for the continent of Europe as well. Since 1880, the Earth’s average surface temperature has crept up by 0.8 degrees Celsius, and most of that warming has occurred in the last three decades.
“This is yet another flag to the politicians, and to all of us”
“This is the latest in a series of warm years, in a series of warm decades,” said Gavin Schmidt, director of NASA’s Goddard Institute for Space Studies. “While the ranking of individual years can be affected by chaotic weather patterns, the long-term trends are attributable to drivers of climate change that right now are dominated by human emissions of greenhouse gases.” The results are an average: some parts of the US − including the Midwest and the East Coast − were unusually cool, while Alaska, California and Nevada all experienced their highest ever temperatures. The Goddard Institute analyses were based on measurements from 6,300 weather stations, ship and buoy-based sea surface temperature measurements, and data from Antarctic research stations. Rowan Sutton, who directs climate research at the National Centre for Atmospheric Science at the University of Reading, UK, said: “By itself, a single year doesn’t tell us too much, but the fact that 14 of the 15 warmest years on record have occurred since the turn of the century shows just how clear global warming has become. This is yet another flag to the politicians, and to all of us.”
Likely to accelerate
And Bob Ward, policy director at the UK’s Grantham Research Institute on Climate Change and the Environment, said the figures exposed the myth that global warming had stopped. The rate of increase in global average surface temperatures had slowed over the last 15 years to about 0.05°C a decade, but was likely to accelerate again. “Measured over a period since 1951, global mean surface temperature has been rising about 0.12°C per decade,” Ward said. “There is mounting evidence all round the world that the Earth is warming and the climate is changing in response to rising levels of greenhouse gases in the atmosphere. “Carbon dioxide levels are close to 400 parts per million − 40% higher than they were before the Industrial Revolution, and probably higher than they have been for millions of years.” No politician, he said, could afford to ignore this overwhelming scientific evidence, or claim that global warming was a hoax. – 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.