It looks as if 2012 will set a new record low for Arctic ice extent. As a measure of the impact of global warming, this is depressingly clear-cut. There’s no need to go into arguments about trends and variability, or use any kind of modelling – the ice is melting visibly.
Source: National Snow and Ice Data Center.
fn1. Satellite data on ice extent goes back to 1979. There are other measures, arguably more relevant, such as estimates of ice volume, for which the data set is shorter. They tell an even gloomier stories.