John Walsh, one of the leading experts on climate change in the Arctic, has devoted much of his career to trying to unravel the secrets of the science and math behind that change.
As the chief scientist at the International Arctic Research Center in Fairbanks, Alaska, he is more qualified than almost anyone to talk about what is happening and what lies ahead.
Walsh joined the faculty in atmospheric sciences at the University of Illinois in 1974, earned his doctorate at the Massachusetts Institute of Technology and has been in Alaska for 17 years. He is not given to hyperbole or overly dramatic comments when he speaks.
“There’s little doubt that the Arctic is warming. We’ve seen some pretty convincing examples of that,” he said in a recent seminar on “Arctic Climate Change: Future Pathways.”
John Walsh: Arctic Climate Change – Alternative Futures from SNAP + ACCAP on Vimeo.
“These changes are unprecedented in the historical record,” he said.
He has also little doubt that conditions in the Arctic in 2100 will be shaped in a major way by whether the world takes steps to reduce carbon emissions from current levels.
Walsh outlined prospects for two dramatically different visions of what the latter decades of this century might look like in the Arctic.
The world can continue along its current path — one likely to lead to accelerating changes in the Arctic. Or it could take steps to reduce carbon emissions and slow the rate of warming by the latter part of this century.
If the current rate of carbon emissions continues, average Arctic winter temperatures by 2100 could be more than 20 degrees Fahrenheit (about 13 degrees Celsius) higher than today, he said.
On the other hand, if the world makes an extreme effort to reverse carbon emissions in 70 years or so, the Arctic climate could stabilize. He said that some scientists contend that the latter scenario is so unlikely that it should not be considered.
“Even if we stopped all emissions that wouldn’t take us into the negative emission range, which that scenario does have in the last few decades. So it assumes carbon sequestration or something equivalent to it,” he said.
The Paris climate agreement — to which the United States was a party, before the Trump administration pulled out — targets limiting emissions by enough to hold the global temperature increase to about 2 degrees Celsius (about 3.6 degrees Fahrenheit).
Walsh said there is always great variability over the short term.
“The ups and downs along the way really complicate the picture of what’s going to happen over time scales of a decade or two,” he said.
These models show the rate of change for the next couple of decades has already been determined by previous emissions.
“That’s means we’re sort of locked in,” he said, but “the dice are loaded though towards extremes that go with warming. “
“It would not be surprising at all if these internal variations resulted in new record high temperatures, new record low ice and snow extent and that type of thing,” he said.
In the longer term, the rate of carbon emissions becomes the biggest factor, he said.
Depending upon human actions, the future of the Arctic ranges from a stabilized climate — under a scenario of zero carbon emissions — to conditions in which changes accelerate with global consequences.
“The choice is ours,” he said.
Walsh said he doesn’t believe the United States will respond to this challenge in he short term.
“In the long term I would tend to be more optimistic. I think the way responses are shaping up, it’s a bottoms up process,” he said, starting at the local level.
“I think other countries are ahead of the U.S. in terms of being proactive,” he said.
‘I’d be optimistic that we can get off of that high emissions scenario curve,” he said.
As to whether the world can stabilize the climate by starting to reverse course on carbon emissions, he has more doubt.
“I really don’t have a good feel for the prospects for carbon sequestration becoming a real viable alternative toward the end of the century,” he said.
Columnist Dermot Cole lives in Fairbanks and can be reached at [email protected]