Arctic may be ice free in four years.

At least, in the summer (BBC):

Scientists in the US have presented one of the most dramatic forecasts yet for the disappearance of Arctic sea ice. Their latest modelling studies indicate northern polar waters could be ice-free in summers within just 5-6 years.

Once again, damn people with their "science" forcing my thesis into obsolescence before it is even finished. Sure, I could revise my methods section. Again. But by the time I am finished, there will be a new study which proves it actually happened 20 minutes ago. Think I am exaggerating? From the same article:

"Our projection of 2013 for the removal of ice in summer is not accounting for the last two minima, in 2005 and 2007," the researcher from the Naval Postgraduate School, Monterey, California, explained to the BBC. "So given that fact, you can argue that may be our projection of 2013 is already too conservative."

My methods are premised around a timeframe of about 50 years, as arctic ice was not expected to disappear until then (and thus free up Churchill for shipping year-round, or as close as matters for the economic impact). Now that could be compressed by more than 40 years and there is the additional possibility of a rapid collapse of the polar bear population followed closely by the ecotourism business it supports.