International team assesses widespread effects of polar warming
With 2019 on pace as one of the warmest years on record, a new study published today in the journal Science Advances, reveals how rapidly the Arctic is warming and examines global consequences of continued polar warming. The study reports that the Arctic has warmed by 0.75oC in the last decade alone. By comparison, the Earth as a whole has warmed by nearly the same amount, 0.8oC, over the past 137 years.
“Many of the changes over the past decade are so dramatic they make you wonder what the next decade of warming will bring,” said lead author Eric Post, a UC Davis professor of climate change ecology. “If we haven't already entered a new Arctic, we are certainly on the threshold.”
What 2 degrees global warming means for the poles
The comprehensive report represents the efforts of an international team of 15 authors specializing in an array of disciplines, including the life, Earth, social, and political sciences. They documented widespread effects of warming in the Arctic and Antarctic on wildlife, traditional human livelihoods, tundra vegetation, methane release, and loss of sea- and land ice. They also examined consequences for the polar regions as the Earth inches toward 2oC warming, a commonly discussed milestone.
“Under a business-as-usual scenario, the Earth as a whole may reach that milestone in about 40 years,” said Post. “But the Arctic is already there during some months of the year, and it could reach 2oC warming on an annual mean basis as soon as 25 years before the rest of the planet.”
The study illustrates what 2oC of global warming could mean for the high latitudes: up to 7oC warming for the Arctic and 3oC warming for the Antarctic during some months of the year.
The authors say that active, near-term measures to reduce carbon emissions are crucial to slowing high latitude warming, especially in the Arctic.
Beyond the polar regions
Major consequences of projected warming in the absence of carbon mitigation are expected to reach beyond the polar regions. Among these are sea level rise resulting from rapid melting of land ice in the Arctic and Antarctic, as well as increased risk of extreme weather, deadly heat waves, and wildfire in parts of the Northern Hemisphere.
“What happens in the Arctic doesn’t stay in the Arctic,” said co-author Michael Mann, a distinguished professor of atmospheric sciences at Penn State. “The dramatic warming and melting of Arctic ice is impacting the jet stream in a way that gives us more persistent and damaging weather extremes.”
Muyin Wang, research meteorologist with the University of Washington Joint Institute for the Study of the Ocean and Atmosphere and NOAA PMEL is a co-author of the research. Other institutions include Pennsylvania State University; Aarhus University; University of Oxford; University of Lapland; University of Colorado, Boulder; Chicago Botanic Garden; Dartmouth College; Umea University; University College London; U.S. Arctic Research Commission; and Harvard University.
Funding for the study was provided by grants from the U.S. National Science Foundation, Academy of Finland and JPI Climate, National Geographic Society, Natural Environment Research Council, the Swedish Research Council, U.S. National Aeronautics and Space Administration, and NOAA.
Originally posted on UC Davis on December 4, 2019.