The Washington PostDemocracy Dies in Darkness

As Trump denies climate change, scientists fear we’re about to blow past the 2-degree red line

In this Monday, Sept. 26, 2016, photo, Republican presidential nominee Donald Trump answers a question during the presidential debate with Democratic presidential nominee Hillary Clinton, at Hofstra University in Hempstead, N.Y. (AP Photo/David Goldman, File)

A new scientific statement released Thursday — underscoring the urgency of grappling with global warming — presented a sharp contrast with the state of public discussion of the subject in the United States.

Here, in the wake of the first presidential debate, the media skewered Republican presidential candidate Donald Trump for denying his prior Twitter claim that “the concept of global warming was created by and for the Chinese”  — even as Trump’s surrogates continued to bluntly advance positions contrary to modern scientific understanding on the subject. His campaign manager Kellyanne Conway, for instance, asserted on CNN that Trump believes the current climate swing is “naturally occurring,” contradicting the view of mainstream climate researchers that it is mainly human-caused.

We just might have a real climate debate in this election. That’s bad news for Trump

On Thursday, a group of seven distinguished climate scientists led by Robert Watson, a former chairman of the United Nations’ Intergovernmental Panel on Climate Change,  asserted that the chance of holding warming to below 1.5 degrees Celsius above pre-industrial levels “has almost certainly already been missed.”  And we could very soon be on an irrevocable path to 2 degrees of warming, they continue, unless countries dramatically up their pledges to cut emissions under the Paris climate agreement — an agreement Trump has said he would “cancel.”

“When you read the Paris agreement, it is absolutely inadequate, with the current pledges, to get on a pathway to 2 degrees Celsius, let alone a pathway to 1.5,” said Watson in an interview with the Post. To be clear: The researchers are happy with the agreement itself, but not with the steps that countries are currently committing to take under it.

Watson said that as of now, on our current emissions trajectory, the world could be at 1.5 degrees above pre-industrial levels in 2030 — less than 15 years — and at 2 degrees by 2050. But because of time lags in the climate system, the actual emissions that would result in those outcomes, and that would have to be averted in order to avoid them, would occur sooner than that.

“I really think the world is definitely on a pathway, as we’re suggesting in that paper, past the 2 degree world,” Watson said. “If you want any hope of getting even close to that 2 degree world, we need to redouble our efforts.”

The statement was signed by Watson and six other researchers, most of whom have previously held prominent positions with the Intergovernmental Panel on Climate Change, which is considered the leading consensus body of international climate science. The co-authors are from Italy, Argentina, Austria, and Brazil, as well as the United States.

The significance of 2 degrees is this: Up until relatively recently, scientists have generally asserted that this level of planetary warming is a kind of red line, beyond which increasingly devastating impacts– such as extensive ice sheet loss and sea level rise, and reduced yields of food crops — would begin to occur. However, as warming has already reached 1 degrees Celsius above pre-industrial levels, and we begin to already see sharp impacts all around us — major ice loss from Greenland and West Antarctica, growing devastation of coral reefs, and much more — it is starting to look more and more as if even 2 degrees would be way too much.

1.5 degrees has thus emerged as the new red-line number– especially for small island states and developing countries. But Watson and his colleagues, like many other researchers, just don’t see how 1.5 degrees can happen, given the warming momentum already unleashed and the time it will take to gradually reduce emissions. Every year, the world is adding an additional 54 or so billion tons of carbon dioxide equivalent emissions to the atmosphere, their report notes.

And the researchers reiterate, as previous analyses have done, that countries’ current pledges under the Paris agreement — which may soon enter into force — don’t really change those kinds of numbers.

“What we’re saying in the paper is, even if all the pledges are realized, our emissions in 2030 will be about the same as they are today, between 50 and 55 gigatonnes of carbon dioxide equivalent,” Watson said.

The researchers therefore assert that countries of the world must rapidly up their levels of ambition when it comes to cutting emissions — but it is not clear how fast they can really do that. For instance, a recent analysis found that even with all of the Obama administration’s favored policies in place, the U.S. is still unlikely to hit its current target of a 26 to 28 percent reduction in emissions below 2005 levels by the year 2025.

All of which may make it even more clear why many climate scientists are increasingly worried by Trump, who not only denies human-caused climate change, but would apparently try to scuttle the Paris agreement entirely.

Read more at Energy & Environment:

The Arctic is being utterly transformed — and we’re just beginning to grasp the consequences

Scientists may have solved a key riddle about Antarctica — and you’re not going to like the answer

The Pacific ‘blob’ caused an ‘unprecedented’ toxic algal bloom — and there’s more to come

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