Arctic

A giant model of a Polar Bear is moved from its position outside the Shell building after Actress Emma Thomson joined Greenpeace climate change activists on September 29, 2015 in London, England. The event was marked as a celebration after the Anglo-Dutch oil company announced yesterday that it was pulling out of Arctic oil drilling.

Dan Kitwood/Getty Images

A giant model of a Polar Bear is moved from its position outside the Shell building after Actress Emma Thomson joined Greenpeace climate change activists on Tuesday in London, England. The event was marked as a celebration after the Anglo-Dutch oil company announced yesterday that it was pulling out of Arctic oil drilling

An aerial view at night of the downtown Chicago skyline. An Arctic air mass is expected to chill much of the Central Plains and the East Coast through Monday with wind-chill temperatures dropping into the single digits overnight in some places.

Kiichiro Sato/AP

A nightime aerial view of downtown in the US city of Chicago

Greenpeace activist Perrett from Britain attends a bail hearing at a regional court in Murmansk...Greenpeace activist Anthony Perrett from Britain attends a bail hearing at a regional court in Murmansk October 16, 2013.

Dmitri Sharomov/Greenpeace/Reuters

Greenpeace activist Anthony Perrett from Britain attends a bail hearing at a regional court on Wednesday in Murmansk, Russia.

A sign warns residents of the arctic Svalbard islands in Norway of the danger from roaming polar bears, May 26, 2013. Svalbard in Norway's high Arctic, is home to 2,500 people and about 3,000 polar bears. Picture taken May 26, 2013. To match NORWAY-ARCTIC/NYAALESUND.

Balazs Koranyi/Reuters

A sign warns residents of the arctic Svalbard islands in Norway of the danger from roaming polar bears. Svalbard is Norway’s high Arctic, is home to 2,500 people and about 3,000 polar bears.