In a 6-3 decision, the Supreme Court of Canada has ruled the federal Liberal government's carbon pricing regime is constitutional — a major decision that allows Ottawa to push ahead with its ambitious plan to ensure every province and territory has a price on carbon to curb greenhouse gas emissions. Some provinces — notably Alberta, Ontario and Saskatchewan — have forcefully opposed the carbon tax, arguing natural resources are in the provinces' jurisdiction under the Constitution.

Much of the influence on climate from air pollution in East Asia is driven by consumption in the developed countries of Western Europe and North America, according to research co-led by McGill University atmospheric scientist Yi Huang.

In a paper published online this week in Nature Geoscience, Huang and colleagues from China, the U.S. and U.K. report that international trade shifts the climate impacts of aerosols -- solid or liquid particles suspended in air -- from net consuming countries to net producing countries.