A sea ice scientist holds a piece of Arctic sea ice core up to the light. The samples are later bagged and taken back to a lab for analysis. Behind him his colleagues drill into the ice to make depth measurements. By using core samples, scientists can put an approximate date on when various parts of an ice floe were formed. This helps them to form models of how sea ice grows, deforms and melts over the years.
© Nick Cobbing / Greenpeace