Global warming hiatus could be a myth

By Maura Forrest

September 24, 2015

The so-called hiatus in global warming over the last 15 years, which has perplexed scientists and given fodder to climate skeptics, may never have happened at all.

New research published in the journal Climatic Change suggests the planet has not stopped warming, and the rate of warming has not declined.

“We find compelling evidence that recent claims of a ‘hiatus’ in global warming lack sound scientific basis,” the authors write.

The team completed a new statistical analysis of global temperature data. “What is clear from analyzing the long-term data in a rigorous statistical framework is that, even though climate varies from year to year and decade to decade, global temperature has increased in the long term, and the recent period does not stand out as being abnormal,” said Noah Diffenbaugh, one of the study’s authors, in a news release.

Reports of a slowdown in global warming have appeared since the turn of the 21st century. Efforts to explain the perceived hiatus generated significant controversy during the drafting of the most recent Intergovernmental Panel on Climate Change report in 2013.

One of the most popular explanations for the hiatus was that natural fluctuations in the Pacific Ocean were pulling heat out of the atmosphere. Though most scientists insisted that the slowdown was just temporary, climate skeptics leapt on the trend as proof that concerns about climate change were overblown.

But now, several papers are suggesting the whole notion of a hiatus could be wrong. Research published earlier this year in the journal Science by the National Oceanic and Atmospheric Administration found that some recent ocean temperature measurements were inaccurate. When corrected, evidence of a global warming slowdown disappeared.

The authors of this most recent paper suggest the hiatus is nothing more than an artifact from faulty statistical methods.

“Our results clearly show that… there never was a hiatus, a pause or a slowdown in global warming,” Diffenbaugh said in the release.

Climate data show that 2014 is the hottest year on record, and 14 of the 15 warmest years have occurred during the 21st century.



Photo Credit: Christopher Michel