It's official: Companies must now purchase permits to emit excess levels of carbon dioxide and other greenhouse gases in the state of California.
Six years after enacting its own law to fight global warming, California conducts its first auction of carbon permits. Companies that give off large amounts of carbon dioxide will need permits to cover the emissions.
Global warming didn't get even a mention in the three presidential debates, but a new study says the U.S. is on track to meet its pledge to reduce emissions by one-sixth. A major reason: the power of federal regulation.
Today a 9th Circuit court in San Francisco hears arguments on the legality of California's, first in the nation, low carbon regulation for transport fuel. The case may determine whether California becomes the U.S. leader in climate litigation.
Shipping across the ice-free Arctic appears closer than ever. The new route will save fuel, but bring emissions and soot directly to the Arctic -- possibly accelerating the ice melt.
The European Union wants airlines to reduce emissions or pay for permits allowing them to pollute. U.S. opponents say the permit fees would be better spent on new, more efficient aircraft.