18 July 2014
In the Boreal forests of Canada there have been huge wildfires this month and the smoke is covering much of Canada. Late images this afternoon show the smoke is moving across the Great Lakes states as well, and it may move into the northeast U.S. soon. This part of the world has warmed more than any other over the past 60 years, and Climate Central has a nice write-up on it here.
A recent paper in PNAS (Abstract is well worth a read) shows that the wildfires are burning far more land now than in the past several thousand years. This would make sense since warmer summers mean lower humidity and drier forests. Below is a closeup image of the smoke over the Great Lakes today and it was very noticeable in Idaho and Wyoming over the last few days as well.