In an effort to stop global warming, environmentalists took a swim in icy Coney Island waters on Saturday.

About one dozen environmentalists jumped in as part of a nationwide movement called the Polar Bear Plunge, whose mission is to keep winter cold. The point of jumping in the water was to raise awareness about climate change.

The Coney Island group wanted to gain public attention specifically about the use of tropical rainforest wood on Coney Island?s boardwalk. The environmentalists said that the deforestation contributes to about a quarter of all greenhouse gas emissions. They said that by using tropical rainforest wood on the boardwalk, the city is contributing to the negative climate impact.