New federal study finds no warming slowdown
WASHINGTON — Global warming hasn’t stopped or even slowed in the past 18 years, according to a new federal study that rebuts claims that heating trends have paused.
Scientists at the National Oceanic and Atmospheric Administration readjusted thousands of weather data points to account for different measuring techniques through the decades. Their calculations show that since 1998, the rate of warming is about the same as it has been since 1950: about two- tenths of a degree Fahrenheit a decade.
The so- called hiatus has been touted by nonscientists who reject mainstream climate science. Those claims have resonated; two years ago, the United Nation’s Intergovernmental Panel on Climate Change felt the need to explain why the Earth was not heating up as expected.
“The reality is that there is no hiatus,” said Tom Karl, director of the National Centers for Environmental Information in Asheville, N. C.
Scientists keep updating the way they measure Earth’s temperatures. This study focuses on the effects of the way ocean temperatures are taken. The old way, going back generations, is with ships. Sometimes people would dip a bucket in the water; other times they would measure water that flowed into the engine. They also did it at various times of day.
The new way is on buoys at the same time of day.
A few years ago NOAA made similar adjustments to make land temperatures more comparable decade to decade. But that also caused some nonscientists who reject climate change to cry tampering.
Several outside scientists said the new and previous adjustments are sound. Kevin Trenberth, climate analysis chief at the National Center for Atmospheric Research, said the new work was “good and careful analysis.”
A few years ago a group out of University of California, Berkeley — funded in part by the Charles Koch Foundation, a major funder of climate doubter groups — took what was initially billed as a skeptical look at the previous NOAA data. But they pronounced the earlier adjustments legitimate.
“NOAA is confirming what we have been saying for some time that the ‘ hiatus’ in global warming is spurious,” Berkeley team chief and physicist Richard Muller said in an email. Muller said global warming continues but in “many fits and spurts.”
John Christy of the University of Alabama in Huntsville, one of the minority of scientists who dispute the magnitude of global warming, said the Karl paper “doesn’t make sense” because satellite data show little recent warming.
Others who reject warming, especially nonscientists, point to satellite records by Remote Sensing Systems that appear to show no change in temperature since 1998.
Carl Mears, senior research scientist for Remote Sensing Systems, said those rejecting climate change based on his work or any one data set are wrong and “seek to deny the reality of human- induced climate change by grasping at straws.”
Mears said the overall data consistently show long- term global warming and that it hasn’t stopped recently. The NOAA adjustments make sense, he said.
Karl said NOAA didn’t adjust data sets in the Arctic because there is a lack of reliable long- term records to compare. Had NOAA made those adjustments, the warming trend would be slightly larger, he said.