To hear the skeptics tell it, there has been no global warming for nearly two decades. In February 2014, GOP presidential candidate Ted Cruz told CNN that “there has been no recorded warming” over the last 15 years. Climate change skeptics concede that, whatever global warming existed before 2000, it has considerably slowed down since the end of the 20th century.
This opinion has taken shape in part by cherry-picking available data and in part from the 2013 assessment report from the Intergovernmental Panel on Climate Change, which posited that the rate of surface warming across the planet entered a hiatus after 1998. But this left many scientists puzzled, especially given that 14 of the last 15 years in this century have yielded the hottest years in recorded history.
Dr. John Abraham, a professor of thermal sciences, has been a vocal critic of the so-called “global warming hiatus,” and has pointed out that, despite varying atmospheric temperatures, the planet’s total thermal energy (heat) is increasing – and that the ocean, which absorbs 90 percent of the planet’s thermal energy, is hoarding a significant portion of the warming puzzle.
Planet Expert Michael Mann has also refuted the global warming “faux pause,” saying the discrepancy between warming models and the IPCC’s assessment is likely due to the “underestimation of the actual warming that has occurred, due to gaps in the observational data,” as well as the failure to include natural factors in model simulations.
It turns out both Drs. Abraham and Mann are absolutely right.
On Thursday, an updated analysis of global surface temperatures was published in the journal Science that, according to the authors, “reveals that global trends are higher than reported by the IPCC, especially in recent decades, and that the central estimate for the rate of warming during the first 15 years of the 21st century is at least as great as the last half of the 20th century.”
The new analysis improves on previous information by utilizing more recent land temperature measurements and improved ocean surface temperature measurements – taken from floating buoys and ship-board sensors instead of buckets tossed overboard (as had been common practice at one time).
Land surface temperature data has markedly improved in recent years, the Smithsonian notes, thanks to efforts in Africa, Asia, South America and the poles to increase the number of data collection stations.
With this new analysis, study co-author Huai-Min Zhang told the Smithsonian that “[t]he notion of a warming hiatus in the most recent decades, as defined by the [IPCC report], is no longer valid. The global warming rate has been just as fast over the last 15 years as over the previous 50 years.”
In fact, the new rate appears to be nearly double the IPCC’s assessment, with very little difference in warming between 2000-2014 and in the latter half of the 20th century.
As Russell Vose, the head of the climate science division at the National Centers for Environmental Information and co-author of the study told Scientific American, “There is no slowdown in global warming. Or stated differently, the trend over the past decade and half is in line with the trend since 1950.”
Dr. Abraham, who has repeatedly dismissed the idea of a global warming hiatus, wrote in the Guardian that this new paper shows “that the warming in the recent years has not stopped and has not even slowed down.”
Gavin Schmidt, the head of the NASA Goddard Institute for Space Studies, has pointed out that this new analysis only changes the warming estimate in the hundredths of degrees. “The fact that such small changes to the analysis make the difference between a hiatus or not merely underlines how fragile a concept it was in the first place,” he said.
Since the late 19th century, temperatures have risen about 1.6°F, and they could rise another 10 degrees by the end of this century if emission trends continue at their current rates. On top of that, Dr. Michael Mann has written that global weather patterns may be on the verge of shifting, diminishing the ocean’s ability to absorb heat and triggering an acceleration in overall warming.