Major global warming study again questioned, again defended

WASHINGTON -- Another round of bickering is boiling over temperature readings used in a 2015 study to show how the planet is warming.

The issue is about how readings gathered decades ago were adjusted to try to get a clearer picture of how the Earth's temperature is changing now. Those adjustments have been questioned by some who reject mainstream climate science and have tried to claim there has been a pause in global warming.

A January study in a scientific journal used another set of measurements to confirm the readings and prove again the Earth's temperature is rising quickly, and warming has not paused.

But a congressional committee Tuesday seized on complaints from a retired scientist from the National Oceanic and Atmospheric Administration about how the original data were handled to claim the data were falsified -- though the retired NOAA scientist they cite does not argue it was.

What is being touted as a scientific scandal is more about data handling than what rising temperatures show, according to phone and email interviews with more than two dozen experts on the issue, including the former government scientist, whose blogging Saturday reignited a debate.

The hubbub was sparked when retired NOAA data scientist John Bates said in a blog post his boss, then-director of the National Centers for Environmental Information Thomas Karl, "constantly had his 'thumb on the scale' -- in the documentation, scientific choices and release of datasets -- in an effort to discredit the notion of a global warming hiatus" and rushed a study published in the journal Science before international climate negotiations.

Bates said Monday he was most concerned about the way data was handled, documented and stored, raising issues of transparency and availability. He said Karl didn't follow crucial data-storage and handling steps Bates created for NOAA. He said it looked as if the June 2015 study was pushed out to influence the December 2015 climate treaty negotiations in Paris.

Bates, who acknowledges Earth is warming from man-made carbon dioxide emissions, said there was "no data tampering, no data changing, nothing malicious."

"It's really a story of not disclosing what you did," Bates said. "It's not trumped-up data in any way, shape or form."

Still, the House Science Committee accused NOAA of playing "fast and loose" with land and water-temperature data.

House Science Committee chairman Lamar Smith, R-Texas, speaking at a hearing Tuesday, called on Science to retract the 2015 study and blasted NOAA for not being cooperative with his subpoenas. When the journal's publisher Rush Holt said the charges don't support a retraction because the issue is more about data procedures than science, Smith, an attorney, interrupted him and insisted: "They falsified global-warming data."

The Karl study looked mostly at ocean temperature records several decades old and determined that those older readings skewed too warm when compared to modern monitoring from buoys and other devices because they were taken in ships' engine rooms. He adjusted those old readings down, which makes it clearer that the earth's temperature is rising now.

Since then, a new independent study from the University of California, Berkeley looked at the same issue in a different way, and confirmed the Karl calculations.

"Not using their data we get the exact same results, both for the ocean record and for the land," said Zeke Hausfather, lead author of the Berkeley study. He called Bates' claims "all about procedural disagreements within NOAA that have very little bearing about our understanding about what's happening to Earth's climate."

Marcia McNutt, who was editor of Science at the time the paper was published and is now president of the National Academy of Sciences, praised Bates for wanting to highlight the importance of data archiving, but said his criticisms have little to do with the main part of the paper and chastised the House for using issues of data archiving to try to discredit the 2015 study.

"The study has been reproduced independently of Karl et al -- that's the ultimate platinum test of whether a study is to be believed or not," McNutt said. "And this study has passed."

The Associated Press interviewed more than two dozen experts by phone or email. Most agreed with Karl or didn't take a side but said it didn't matter because global warming continues regardless of this latest kerfuffle. Two supported Bates, saying there were serious scientific integrity concerns.

As far as the study being rushed, the journal says its records show otherwise. Science's new editor-in-chief Jeremy Berg said it usually takes 109 days between a paper's submission and its publication. The Karl study was received by the journal on Dec. 23, 2014 and published 185 days later, on June 26, 2015.

"The paper was not rushed in any way," McNutt said. "It had an exceptional number of reviewers, many more than average because we knew it was on a controversial topic. It had a lot of data analysis."