This story was adapted from a version published by the University of California, Davis. .
With 2019 on pace as one of the warmest years on record, a major new study from an international team of researchers reveals how rapidly the Arctic is warming and examines global consequences of continued polar warming. 听
The study, and led by the University of California, Davis, reports that the Arctic has warmed by 0.75 degrees Celsius in the last decade alone. By comparison, the Earth as a whole has warmed by nearly the same amount, 0.8 degrees Celsius, over the past 137 years.
Such changes in the poles can also have dramatic consequences for the rest of the world, said Michael Gooseff, a professor in the Department of Civil, Environmental and Architectural Engineering at 彩民宝典.听
Top: Michael Gooseff surveys the degradation of permafrost in Alaska; bottom: Gooseff walks over Antarctica's Lake Fryxell. (Credits: Michael Gooseff)
Antarctica鈥檚 ice sheets, for example, hold 90% of the planet鈥檚 freshwater, a tremendous supply that could shift the dynamics of oceans worldwide.听
鈥淭he poles are connected to the rest of the Earth,鈥� said Gooseff, a coauthor of the new study. 鈥淲hat happens at the poles has consequences to weather and sea level around the world.鈥�
鈥淢any of the changes over the past decade are so dramatic they make you wonder what the next decade of warming will bring,鈥� said lead author Eric Post, a UC Davis professor of climate change ecology. 鈥淚f we haven't already entered a new Arctic, we are certainly on the threshold.鈥�
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 2 degrees Celsius warming, a commonly discussed milestone.
鈥淯nder a business-as-usual scenario, the Earth as a whole may reach that milestone in about 40 years,鈥� said Post. 鈥淏ut 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.鈥�
The study illustrates what 2 degrees Celsius of global warming could mean for the high latitudes: up to 7 degrees Celsius warming for the Arctic and 3 degrees Celsius 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.听
Post emphasizes that major consequences of projected warming in the absence of carbon mitigation are also 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.
鈥淢any polar ecosystems have shown resilience to state changes,鈥� said Gooseff. 鈥淏ut there鈥檚 an expectation that continued warming of polar regions will push many systems beyond tipping points.鈥�
Coauthoring institutions include Pennsylvania State University; Aarhus University; University of Oxford; University of Lapland; Chicago Botanic Garden; Dartmouth College; University of Washington; Umea University; University College London; U.S. Arctic Research Commission; Harvard University; and National Oceanic and Atmospheric Administration (NOAA).
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.
