Over the past century, average global temperatures have increased by 1.3 degrees. Higher temperatures have been linked to rising carbon emissions. Scientists warn of devastating effects if the earth warms by another two degrees. As Washington faces another debt showdown, support is rising for a carbon tax as a free-market solution to climate change. And California’s new law puts a cap on carbon emissions. But opponents argue these policies kill jobs and burden low-income consumers. For this month’s Environmental Outlook: the economics and politics of reducing carbon emissions.