Who: It's the "ice".

When: Now

Where: Arctic

What: The Arctic Ocean is gradually becoming warmer and less salty then before. Due to the highness of he temperature now, the sea ice are melting.

Why: These effects are made by the fact of global warming that is now occurring.

Link:

http://news.bbc.co.uk/cbbcnews/hi/newsid_7670000/newsid_7675400/7675401.stm