Loss of Arctic Sea Ice Affects Weather in Europe and North America

Aerial view of low water level in drought conditions at Lake Shasta in California, 2014. DWR (Department of Water Resources), California.
Arctic loss of sea ice is connected to changes in the weather in Europe and North America and lower latitudes in general. However, the political reaction still seems weak.

Scientific studies demonstrating this link are making quick progress. This has crucial implications for people around the world. However, the political reaction still seems weak.

Changing weather patterns

“There is more and more scientific evidence that the changes in the Arctic are affecting the mid-latitude weather,” states Ivana Cvijanovic, research scientist and Beatriu de Pinós Fellow at the Barcelona Supercomputing Center. As the Arctic is warming faster than any other region, “this affects the temperature difference between the pole and the equator, as well as the atmospheric heat transport from the lower into the higher latitudes,” Cvijanovic explains. These factors, in turn, have an important impact on the weather in regions other than the Arctic.

Global consequences

Research on how Arctic warming affects other parts of the globe has substantial worldwide implications. “It was an important step to understand and acknowledge that the problem of a warming Arctic is not just a problem for local people but that its impacts will be felt around the world,” says Cvijanovic about the societal implications of the scientific results.

However, the urgency implied by the research findings appears to be disconnected to the political reactions. The researcher acknowledges: “While the scientific understanding of the remote impacts is advancing, the political response remains weak.”

Call to action

Cvijanovic points to the various aspects affected by climate change in the Arctic, which haven’t received their fair share of attention in policy-making. She confirms: “For numerous places around the world, inaction now means dire consequences for biodiversity, agriculture, food safety, water availability and economy in the not so distant future.”

She continues: “At that point, I assume that some sort of accountability will be demanded from parties that ignored the scientific warnings. But clearly, we should be acting now.” Her recommendations for action are very clear: “Taking control of our greenhouse gas emissions and decreasing them.”

Substantial advances in research

“Initially, it was only possible to link changes in certain large-scale features,” Cvijanovic remembers. One example is the connection between mid-latitude wind strengths and changes in Arctic sea ice cover. Cvijanovic enthusiastically comments: “But lately, scientists have been trying to relate and attribute actual extreme weather episodes to certain states and geometries of sea ice cover. This is a huge step forward.”

Sea ice affects rainfall in lower latitudes

In particular, Cvijanovic and her colleagues examine the impact on rainfall patterns resulting from changes in the Arctic sea ice cover. They presented their latest findings at the annual meeting of the European Geophysical Union (EGU) in Vienna, Austria.

The scientists found that “the loss of Arctic sea ice cover imposes opposite influences on Californian and Mediterranean winter rainfall” and in general is “an important driver of low-latitude precipitation changes.”

Droughts in California, rain in the Mediterranean

In the case of California and the American southwest, the loss of Arctic sea ice results in precipitation decrease and significant drying due to a complex connection through which winter storms are stirred away from California. This might also explain the Californian period of drought from 2012 to 2016, one of the worst droughts on record.

In contrast to California, the loss of sea ice has a more direct impact on the Mediterranean, where it leads to increasing winter rainfall.

New approach improves understanding

To get to these findings, the researchers developed a “new approach for isolating the impacts of sea ice loss on climate,” which does not add artificial energy fluxes into the high latitudes to simulate a decrease in sea ice cover, unlike most of the existing studies. This solves the problem of “deciphering if the observed climate response originated from the sea ice changes alone or if it has also been impacted by the energy added.”

Antarctic potential influence

Similar to the Arctic, sea ice changes in the Antarctic can also potentially influence the weather across the Northern Hemisphere. However, sea ice losses in the Antarctic have to date been modest compared to the Arctic. In the future, which will presumably see the Antarctic sea ice cover diminish more drastically, research is likely to explore this connection in more detail.