Yesterday, a massive ice island four times the size of Manhattan snapped off of Greenland's Petermann Glacier. Ominous, no? A disturbing sign of a warming planet? Well… actually, it's hard to say. It's true that, in a broad sense, Greenland has been losing ice faster than it has been accumulating snow in recent years. The thing's clearly melting. But linking this one specific glacier calving to global warming is more difficult, and something many glaciologists are reluctant to do.
The way we're warming the planet, we can probably expect sea levels to rise at least a meter, on average, by the end of the century. That's what most scientific projections suggest, anyway. One kink, though, is that that's just an average—the seas won't go up uniformly by one meter all across the globe. Some places will see much higher rises than that, some places much lower. Michael Lemonick has a great Environment360 piece delving into some of the factors that make sea-level rise so odd and unpredictable.
Here's a handy animated map from NOAA showing all the places on the planet where it's unseasonably warm and unseasonably cool right now. Curiously, the freak cold seems to be occurring everywhere major media centers are located—the northeastern United States, Europe, Japan—so the chilly weather's grabbing all the headlines. But it's anomalously warm just about everywhere else in the world, especially the Arctic. (For more on the overall trends, see Joe Romm's post.) Oh, there's one other big exception: It seems to be anomalously cold in Antarctica right now.
One of the quirks of global warming is that average temperatures in the polar regions are rising a lot faster than they are in the rest of the world. (See here for an explanation.) That's not exactly reassuring, since a lot of the climate impacts we care about, especially the melting of Greenland and Antarctic glaciers and the potential release of methane gas from the tundra, will occur in exactly those areas.