Press Trust Of India
Washington, Nov 21: Missing Arctic temperature data created the seeming slowdown of global warming from 1998 to 2012, according to a study.
Researchers at University of Alaska Fairbanks (UAF) in the US constructed the first data set of surface temperatures from across the world that significantly improves representation of the Arctic during the “global warming hiatus.”
Xiangdong Zhang from UAF and colleagues at Tsinghua University in Beijing analysed temperature data collected from buoys drifting in the Arctic Ocean.
“We recalculated the average global temperatures from 1998-2012 and found that the rate of global warming had continued to rise at 0.112 degrees Celsius per decade instead of slowing down to 0.05 degrees Celsius per decade as previously thought,” said Zhang.
The new data also improved estimates of the global warming and the Arctic warming rate. “We estimated a new rate of Arctic warming at 0.659 degrees Celsius per decade from 1998-2014. Compared with the newly estimated global warming rate of 0.130 degrees Celsius per decade, the Arctic has warmed more than five time the global average,” Zhang said in the study published in the journal Nature Climate Change.
The team developed new methods of incorporating the Arctic temperature data into global temperature data so that they could better estimate the average temperatures. Most current estimates use global data that tend to represent a long time span and provide good coverage of a global geographic area.
However, the remote Arctic lacks a robust network of instruments to collect temperature data. Zhang said the study expands on National Oceanic and Atmospheric Administration (NOAA) research and other recent studies that have either supported or refuted the idea of a “global warming hiatus” by reestimating the average global temperatures during that time period with more accurate and representative data. The global warming hiatus is a much-debated topic among climate researchers.
Some scientists theorised that an unusually warm El Nino in the years 1997-1998 and an extended period afterwards without occurrence of El Nino in the tropical Pacific Ocean may have disrupted the rate of global warming.
The Earth’s average global temperatures have been rising over the past century and accelerating as more human produced carbon dioxide enters and lingers in the atmosphere, which is why the idea of “global warming hiatus” seemed baffling.
However, the new data set and resulting estimates show conclusively that global warming did not take a break, said Zhang.
