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If man’s impact on climate goes unchecked, global warming could inflict devastating long-term effects on the environment, economy and public health, warn U.S. government scientists in a major new report.
But while some heard the 1,600-page National Climate Assessment as a blaring distress call, others were less alarmed.
On NBC’s Meet the Press, Danielle Pletka, a foreign policy expert at the conservative American Enterprise Institute, allowed that climate change is happening, but hastened to add that she didn’t know if it’s caused by humans. (In fact, scientists say they are the main contributor.)
She argued the issue of climate change is subject to "hysteria" and said certain weather phenomena, like periods of global cooling, are overlooked by the mainstream media narrative.
"We need to also recognize that we just had two of the coldest years, biggest drop in global temperatures that we have had since the 1980s, the biggest in the last 100 years," Pletka said during a panel discussion. "We don't talk about that because it's not part of the agenda."
Climate scientists told us that part of Pletka’s claim is false and part is misleading.
Pletka said we just had two of the coldest years on record. That’s wrong.
Gavin Schmidt, a climatologist and director of NASA's Goddard Institute for Space Studies, pointed us to a chart of NASA data showing global average temperatures over time:
The far-right dots represent the global temperatures of 2017 and 2016. According to this data, they are actually some of the warmest years on record — which contradicts this portion of Pletka’s claim.
We’d note that the National Oceanic and Atmospheric Administration, which has a slightly different way of calculating temperature, shows 2016 and 2015 as the warmest years on record.
In the United States, according to NASA data, 2017 and 2016 were the second- and third-warmest years.
The other piece of Pletka’s claim — about cold spells — was not so much false, as misleading.
She told us she was relying on an article from Real Clear Markets with the headline, "Did You Know the Greatest Two-Year Global Cooling Event Just Took Place?"
The April 2018 article notes that from February 2016 to February 2018 (the latest month available at the time), global average temperatures dropped 0.56 degrees C.
"You have to go back to 1982-84 for the next biggest two-year drop," the article states, referring also to the NASA data on global average temperatures. (The 1982-84 drop was 0.47 degrees C.)
Climate scientists told us this is technically true, but that it misses the bigger trend that’s taken place over decades.
"Basically, it’s just a statistical fluke that people have grabbed because it sounds good," Schmidt said. "It has no relevance for the long-term trends."
The drop in temperatures after 2016 was also unsurprising, climatologists said.
2016 was especially hot because it was at the peak of the last El Niño, a recurring event when the surface of the Pacific Ocean warms, leading to higher global average temperatures of a few tenths of a degree. As the event concluded, things cooled off.
"So the subsequent drop in temperature isn't surprising," said Judith Curry, a climatologist and former chair of the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology. "A two-year trend is not meaningful in terms of understanding anything about how climate is changing."
The Real Clear article is ostensibly a critique of the mainstream media’s failure to cover cold spells, which the author argues should garner as much coverage as heat waves and extreme weather phenomena linked to climate change. ("None of this argues against global warming," the author states.)
Pletka said, "We just had two of the coldest years, biggest drop in global temperatures that we have had since the 1980s, the biggest in the last 100 years."
Her claim that we just had two of the coldest years is wrong. Globally, 2016 and 2017 were the two warmest years on record, according to one measure.
Climate scientists told us a two-year trend is meaningless in terms of understanding anything about how climate is changing.
With that in mind, Pletka’s assertion that we’ve recently seen the biggest drop in global temperatures is a red herring. It’s based on a cherry-picked statistical fluke of no relevance, compared with long term trends.
Bottom line: Cold spells can and do happen, but they do not negate the fact that global warming is real and a legitimate cause for concern, according to broad scientific consensus.
We rate Pletka’s claim False.
Transcript, NBC’s Meet the Press, Nov. 25, 2018
Fourth National Climate Assessment, Nov. 23, 2018
GISS Surface Temperature Analysis, accessed Nov. 26-27, 2018
NOAA, "2017 was 3rd warmest year on record for the globe," Jan. 18, 2018
PolitiFact, "Rick Perry wrongly downplays human role in climate change," June 22, 2017
Real Clear Markets, "Did You Know the Greatest Two-Year Global Cooling Event Just Took Place?" April 24, 2018
Email interview with Danielle Pletka, a foreign policy expert at the American Enterprise Institute, Nov. 26, 2018
Email interview with Judith Curry, a climatologist and former chair of the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology, Nov. 26, 2018
Email interview with Kerry Emanuel, a climate scientist and meteorologist at MIT, Nov. 26, 2018
Email interview with John Reilly, co-director of the Joint Program on the Science and Policy of Global Change at the MIT Sloan School of Management, Nov. 26, 2018
Email interview with Kevin Trenberth, Distinguished Senior Scientist in the Climate Analysis Section at the National Center for Atmospheric Research, Nov. 26, 2018
Email interview with Gavin Schmidt, a climatologist and director of NASA's Goddard Institute for Space Studies, Nov. 26-27, 2018
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