It's too late to stop summer Arctic sea ice melting — even in a low-emissions scenario that caps global warming at a 1.5°C target in line with the Paris Agreement, according to a new study.
Why it matters: The peer-reviewed findings on the effects of human-caused climate change in the region, published in Nature Communications, suggest the first ice-free summer could be in the 2030s. That's a decade sooner than previously projected.
Thought bubble: Many
studies have projected when the Arctic sea ice would be seasonally
ice-free, and all could be proven wrong given the nonlinearities and
variability inherent in the Arctic climate system.
- One thing
is for sure though, there are going to be surprises, many of them in a
warmer, less ice-covered direction. Using different techniques to
examine these questions is valuable, since the region is already heating
up so quickly. That applies to the climate and geopolitics.
What they did: Researchers examined satellite data and climate models from 1979-2019 to see how Arctic sea ice has changed.
- They used this information to model future melting.
What they found: The
researchers discovered the models underestimated the pace of melting
compared with observations of ice in the Arctic over the period they
examined, according to the study.
- "By scaling models' sea ice
response to greenhouse gases to best match the observed trend in an
approach validated in an imperfect model test, we project an ice-free
Arctic in September under all scenarios considered," wrote the
researchers in the study, led by Seung-Ki Min of Pohang University.
- "These
results emphasize the profound impacts of greenhouse gas emissions on
the Arctic, and demonstrate the importance of planning for and adapting
to a seasonally ice-free Arctic in the near future."
Threat level: "[W]e
may experience an unprecedented ice-free Arctic climate in the next
decade or two, irrespective of emission scenarios," per the study.
- This
would affect human society and the ecosystem both within and outside
the Arctic, through changing Arctic marine activities as well as further
accelerating the Arctic warming,” the researchers wrote.
By the numbers: The
research indicates that 90% of the melting in the region is due to
human-caused global heating and natural factors account for the
remainder.
What they're saying:
Julienne Stroeve, a senior scientist at the NSIDC who was not involved
in the study, said in an emailed statement Tuesday it's impossible to
give an exact date to when an ice-free summer will emerge.
- "This
is because we cannot predict atmospheric conditions and the ice is
quite sensitive to the the year-to-year weather variability and we also
do not have long-enough or trustworthy records of ice thickness to know
if the ice is so thin it would suddenly melt out," Stroeve said.
- "With
others I have looked at using today's ice thickness estimates from
satellite together with the weather conditions of summer 2007 and 2012
and we didn't find we had a more massive loss of ice that we had during
those two summers.
- "This implies that the ice cover is still somewhat resilient to completely disappearing in today’s climate state."
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