Europe has the largest market for carbon permits in the world. The idea is, the more a company has to pay for permits to pollute, the greater incentive it has to reduce pollution. But the economic slowdown has greatly reduced the cost of permits.

That staple of '50s kitchen counter tops is being embraced by young architects as a green alternative to stone.

In our Petro-State podcast, we talk to Michael Levi of the Council on Foreign Relations about the potential of natural gas to transition us to a low-carbon future. And we play fracking BS Detector.

Sellers want a bigger market, but buyers say that will lead to higher prices.