by Joe Romm Posted on June 5, 2015 at 12:03 pm climateprogress.org
A major new study from NOAA finds more evidence that we may be witnessing the start of the long-awaited jump in global temperatures. As I reported in April, many recent studies have found that we are about to enter an era of even more rapid global warming. Indeed, one March study, “Near-term acceleration in the rate of temperature change,” warns the speed-up is imminent — with Arctic warming rising a stunning 1°F per decade by the 2020s. The new study in Science from a team of NOAA scientists, “finds that the rate of global warming during the last 15 years has been as fast as or faster than that seen during the latter half of the 20th Century,” as NOAA explains. The director of NOAA’s National Centers for Environmental Information, Thomas Karl, told the UK Guardian that “considering all the short-term factors identified by the scientific community that acted to slow the rate of global warming over the past two decades (volcanoes, ocean heat uptake, solar decreases, predominance of La Niñas, etc.) it is likely the temperature increase would have accelerated in comparison to the late 20th Century increases.”
What happens when these various temporary factors stop? Karl explained: “Once these factors play out, and they may have already, global temperatures could rise more rapidly than what we have seen so far.”
In other words, the long-awaited jump is global temperatures is likely imminent. How big is the jump? As I reported in April, top climatologist Kevin Trenberth has said it would be as much as 0.5°F. Given that 2015 is crushing it for the hottest year on record, we appear to be already witnessing a big piece of that jump.
NOAA’s new study not only incorporates the latest global temperature data from 2013 and 2014. Their “calculations also use improved versions of both sea surface temperature and land surface air temperature datasets” (detailed here). The result, as NOAA explains, is that the new “study refutes the notion that there has been a slowdown or ‘hiatus’ in the rate of global warming in recent years.” In particular, the authors conclude bluntly: “Indeed, based on our new analysis, the IPCC’s statement of two years ago – that the global surface temperature “has shown a much smaller increasing linear trend over the past 15 years than over the past 30 to 60 years” – is no longer valid.”….