National Geographic photographer Paul Nicklen is joining us at midday on Friday for a live chat about his internationally acclaimed work.
Click here to see some of Paul Nicken's photos
Nicklen has specialised in photos depicting the effects of climate change on polar landscapes since 1995.
A childhood among the Inuit in Canada's Arctic and a background as a biologist in the Northwest Territories help him work in the most inhospitable places on Earth.
His feats include ice diving among leopard seals in Antarctica, covering hundreds of miles of terrain in -40F temperatures and mastering the art of taking aerial shots from his ultralight plane.
