Four nations map course to carbon-free economies

MARRAKESH, Morocco: When it comes to purging fossil fuels from the global economy by mid-century -- our only hope of staving off catastrophic climate change -- it turns out that you can’t get there from here without a good map.

That’s the thinking behind detailed, long-term plans for switching from dirty to clean energy unveiled this week by the United States, Canada, Mexico and Germany at the United Nations climate talks in Marrakesh.