Hot summers causing Arctic sinkholes: study
Arctic sinkholes are appearing across the Canadian High Arctic as permafrost -- ice expected to be frozen year-round -- thaws and collapses due to climate change, according to research published Monday.

"Arctic sinkholes are appearing across the Canadian High Arctic as permafrost — ice expected to be frozen year-round — thaws and collapses due to climate change, according to research published Monday.

“Researchers found maximum thaw depths had already exceeded what they had expected to occur by 2090, according to the report published in Geophysical Research Letters journal.

“At one site, Mould Bay, the level of thawing was 240% higher than historic norms.”

CNN.COM