There's good news from the Arctic today. Sea ice levels are building up, after years of melt. The Cryosat satellite has just recorded 9000 cubic kilometres of ice - 50% more than last year.
Scientists watch both the extent of Arctic ice - the area it covers - and its thickness. This year, both the extent and the thickness have increased.
But I'm not celebrating yet. We used to have over 20,000 cubic kilometres of Arctic ice - more than twice as much as now. Will it ever fully recover?