The northern pole is warming at a rapid pace and hurtling towards a 2 C temperature rise faster than the rest of the planet, researchers writing in Science Advances have warned. "If we haven't already entered a new Arctic, we are certainly on the threshold," said Eric Post, a professor of climate change ecology at the University of California, Davis, and lead author of the report.
This will hurt polar bears and other ice-dwelling species, whose habitat will melt. But from rising sea levels to extreme weather events closer to the equator, warmer poles will affect us all.
The report, published on Wednesday, draws on the expertise of 15 researchers from a cross-selection of disciplines, ranging from the life sciences to political science—and explains just what can be expected in a warmer world, including rising methane (CH4) emissions caused by thawing permafrost.
"Many of the changes over the past decade are so dramatic they make you wonder what the next decade of warming will bring," Post said in a statement.
The Earth has already seen 0.8 C of warming since the late 19th century. The Arctic, in contrast, has seen more than double that, experiencing 2-3 C warming within the same time-frame. In the last decade alone, the northern pole warmed 0.75 C.
The trend is expected to continue as the planet continues to warm. This means the Arctic will likely be 4°C warmer in a 2°C warmer world. While warming isn't predicted to be as extreme in the southern hemisphere, the Antarctic is still on track to see an annual warming of 2°C and a winter warming of 3°C.
As the authors of the paper point out, the environmental consequences of Arctic warming are "unlikely to be limited to the northern high latitudes." For one, countries closer to the equator can expect to see more instances of extreme weather at least partially driven by changes to the jet streams.
Land loss and glacial melt will also contribute to a sea-level rise that predictions suggest could be as high as 10 feet if certain thresholds are passed—a scenario that could leave cities like Amsterdam, St. Petersburg and Los Angeles underwater, according to data collected by the IPCC, NASA and others.
There will also be a direct impact to the animals that call the Arctic and Antarctic their home. As the authors point out, falls in the number of caribou have been linked to changes in shrub cover related to shrinking ice cover in the Northern Hemisphere. Certain penguin species are migrating to breeding grounds that were previously unused and polar bears have had ice melt to contend with, a situation only likely to get worse as scientists say there may be ice-free summers in the northern pole within decades.
"As sea ice has declined, polar bears have been forced ashore for longer and longer periods," Steven Amstrup, chief scientist at Polar Bears International, told Newsweek. "In western Hudson Bay they are now on land for nearly a month longer than 30 years ago. There is a limit to how long they can fast. Therefore, less access to sea ice ultimately means fewer polar bears."
The number of polar bears in the southern Beaufort Sea of Alaska fell approximately 40 percent in the first decade of the 21st century, said Amstrup, who was not involved in the study. The population in Hudson Bay, Canada, has seen declines of around a third since the eighties. "In a nutshell, as the sea ice goes, so goes the polar bear."
The study's authors argue mitigation can slow or reduce warming as well as the expansion of monitoring programs like the U.S. Arctic Observing Network or British Antarctic Study.
"Given the implications of this warming, it is essential to also accelerate efforts to better understand, prepare for, and be able to address the environmental, ecological, and societal changes that will result from continued high-latitude warming," the report states.
"Short of halting greenhouse gas rise, however, there is no ultimate fix," said Amstrup.
