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Arctic Ice Loss Driven By Natural Swings, Not Just Mankind, Says Study (reuters.com)
Alister Doyle, reporting for Reuters: Natural swings in the Arctic climate have caused up to half the precipitous losses of sea ice around the North Pole in recent decades, with the rest driven by man-made global warming, scientists said on Monday. The study indicates that an ice-free Arctic Ocean, often feared to be just years away, in one of the starkest signs of man-made global warming, could be delayed if nature swings back to a cooler mode. Natural variations in the Arctic climate "may be responsible for about 30-50 percent of the overall decline in September sea ice since 1979," the U.S.-based team of scientists wrote in the journal Nature Climate Change. Sea ice has shrunk steadily and hit a record low in September 2012 -- late summer in the Arctic -- in satellite records dating back to 1979. The ice is now around the smallest for mid-March, rivaling winter lows set in 2016 and 2015. The study, separating man-made from natural influences in the Arctic atmospheric circulation, said that a decades-long natural warming of the Arctic climate might be tied to shifts as far away as the tropical Pacific Ocean.
Just a bad summary... this article is better: https://www.sciencedaily.com/r...
"Anthropogenic forcing is still dominant -- it's still the key player," said first author Qinghua Ding, a climate scientist at the University of California Santa Barbara who holds an affiliate position at the UW, where he began the work as a research scientist in the UW's Applied Physics Laboratory. "But we found that natural variability has helped to accelerate this melting, especially over the past 20 years." ...
"In the long term, say 50 to 100 years, the natural internal variability will be overwhelmed by increasing greenhouse gases," Ding said. "But to predict what will happen in the next few decades, we need to understand both parts."
Read the article...
30-50% of the warming is due to natural, not man made, effects.
Or, as scientists have been saying for decades, the majority of the warming (50 - 70%) is due to man made effects.
This includes scientists at shell oil and Exxon-Mobil. I remember debate class in high school, fall of 1979, our team was 'pro' nuclear power. We used research from oil companies about the dangers of global warming as one one the arguments in favor of expanding nuclear power use. We won the debate, despite the fact that the 3 mile island accident happened in spring of '79. That made it a very tough debate to win the pro nuclear side of the argument.
This is not the paper described in the summary, but rather an older paper with some of the same authors. The paper referenced in the summary was published online yesterday in Nature Climate Change. I'm sorry that I can't give a direct link to a .pdf (yay for paywalls keeping all of the non-ivory tower plebs out! huzzah!), but for those with access, the paper can be found at Influence of high-latitude atmospheric circulation changes on summertime Arctic sea ice. For those without access to an academic library, the first author provides an email contact. One presumes that a polite request would yield the full text of the paper.
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