Melting

This year's thinner, slushier ice is more vulnerable than the past's thick, multi-year ice, and it melts out rapidly during a spike in temperature or intense cyclonic activity.

• By Gloria Dickie

In a warming climate, polar bears face a dramatically changing future. If they'll cope is still uncertain.

• By Francie Diep

A new study shows that melting glaciers have contributed to a taller Iceland.

• By Wes Judd