By Sid Perkins
The amount of soot wafting to the Arctic has increased significantly since the beginning of the Industrial Revolution but isn’t nearly as high now as it was a century ago, an ice core from Greenland suggests.
Greenland has always received some soot from Canadian wildfires, says Joseph R. McConnell, a hydrologist at the Desert Research Institute in Reno, Nev. But the load increased around 1850, when mills and power plants in Canada and elsewhere in the Northern Hemisphere began burning coal in large quantities.