Extremes become routine in an emerging new #Arctic — Nature #ClimateChange #ActOnClimate #KeepItInTheGround

In this image proved by the European Space Agency, ESA, showing the glacier section that broke off the fjord called Nioghalvfjerdsfjorden, bottom, which is roughly 80 kilometers (50 miles) long and 20 kilometers (12 miles) wide, the National Geological Survey of Denmark and Greenland said Monday Sept. 14, 2020. The glacier is at the end of the Northeast Greenland Ice Stream, where it flows off land and into the ocean. Scientists with National Geological Survey see it as evidence of rapid climate change leading to the disintegration of the Arctic’s largest remaining ice shelf. (European Space Agency via AP)

Access the report here. Here’s the abstract:

The Arctic is rapidly warming and experiencing tremendous changes in sea ice, ocean and terrestrial regions. Lack of long-term scientific observations makes it difficult to assess whether Arctic changes statistically represent a ‘new Arctic’ climate. Here we use five Coupled Model Intercomparison Project 5 class Earth system model large ensembles to show how the Arctic is transitioning from a dominantly frozen state and to quantify the nature and timing of an emerging new Arctic climate in sea ice, air temperatures and precipitation phase (rain versus snow). Our results suggest that Arctic climate has already emerged in sea ice. Air temperatures will emerge under the representative concentration pathway 8.5 scenario in the early- to mid-twenty-first century, followed by precipitation-phase changes. Despite differences in mean state and forced response, these models show striking similarities in their anthropogenically forced emergence from internal variability in Arctic sea ice, surface temperatures and precipitation-phase changes.

From The New York Times (Henry Fountain):

Open water and rain, rather than ice and snow, are becoming typical of the region, a new study has found.

The effects of global warming in the Arctic are so severe that the region is shifting to a different climate, one characterized less by ice and snow and more by open water and rain, scientists said Monday.

Already, they said, sea ice in the Arctic has declined so much that even an extremely cold year would not result in as much ice as was typical decades ago. Two other characteristics of the region’s climate, seasonal air temperatures and the number of days of rain instead of snow, are shifting in the same way, the researchers said.

The Arctic is among the parts of the world most influenced by climate change, with sharply rising temperatures, thawing permafrost and other effects in addition to shrinking sea ice. The study, by Laura Landrum and Marika M. Holland of the National Center for Atmospheric Research in Boulder, Colo., is an effort to put what is occurring in the region in context.

“Everybody knows the Arctic is changing,” said Dr. Landrum, a climate scientist and the lead author of the study, published in the journal Nature Climate Change. “We really wanted to quantify if this is a new climate.”

In other words, she said, “has the Arctic changed so much and so fast that the new climate cannot be predicted from the recent past?”

From The Associated Press:

Annual end-of-melt-season changes for the Arctic’s largest ice shelf in Northeast Greenland are measured by optical satellite imagery, the survey known as GEUS said. It shows that the area’s ice losses for the past two years each exceeded 50 square kilometers (19 square miles).

The ice shelf has lost 160 square kilometers (62 square miles), an area nearly twice that of Manhattan in New York, since 1999.

“We should be very concerned about what appears to be progressive disintegration at the Arctic’s largest remaining ice shelf,” said GEUS professor Jason Box…

Last week, Ruth Mottram, an ice scientist at the Danish Meteorological Institute in Copenhagen, said, “again this year, the ice sheet has lost more ice than has been added in the form of snow.”

Leave a Reply