Decadal climate variability and the early-2000s hiatus

• Other Authors: Meehl, Gerald (author)
• Format: Article in Journal/Newspaper
• Language: English
• Published: U.S. Global Change Research Program 2015
• Subjects: Arctic; Pacific; Global warming
• Online Access: http://nldr.library.ucar.edu/repository/collections/OSGC-000-000-022-290

There have been recent claims that the early-2000s hiatus (or more accurately a slowdown; the term “hiatus” will be used here to denote that slowdown), when the rate of global warming slowed compared to the previous two decades, was an artifact of problematic sea surface temperature (SST) data (Karl et al. 2015), lack of Arctic data (Cowtan and Way 2014), or both. Such claims indicate that when corrections are made to SST data, by taking into account various measurement methods that introduce biases in the data, then “there was no ‘hiatus’ in temperature rise…[and] a presumed pause in the rise of Earth’s average global surface temperature might never have happened” (Wendel 2015). Often there are issues with observed data that need adjusting -- in this case such claims of “no hiatus” are artifacts of questionable interpretation of decadal timescale variability and externally forced response - not problems with the data. Thus, the hiatus is symptomatic of the much broader and very compelling problem of decadal timescale variability of the climate system. Recent research has shown that decadal variability in the Pacific associated with the Interdecadal Pacific Oscillation (IPO) plays a major role in driving naturally-occurring global decadal timescale climate fluctuations that are superimposed on the long term warming trend from increasing greenhouse gases (GHG) emissions throughout the 20th and early 21st centuries.