Cap And Trade

It's a government program designed to make pollution into tradeable units. So, for a given unit of pollution, polluters pay a tax, the money from which will presumably get used to do something offsettingly good for the environment. Meanwhile, companies can trade these units amongst themselves.

The goal here was to set baseline maximums of a pollutant. Meanwhile, there's still some flexibility for companies that need to do extra polluting to get their business done (they can just buy units from other, greener companies). All this makes fighting pollution a market-based thing.

The Obama Administration set a carbon emissions limit and the big controversy revolved around whether that amount of 'okay' carbon emissions was the right number. The whole walla became a political football. But economists on both sides have lauded the notion of trying to use markets to fight pollution, since spitting pollutants into the atmosphere has thus far, more or less, been free. Sorry Polar Bears. We probably won't figure this out until you're all dead.