What is Climate Law?

There has been little scholarly consideration of what climate law is, and no settled definition of climate law has yet emerged. I show that climate law is best conceived of as having two forms: a law that compels action and a law that incentivizes it (other than through compulsion). Both forms of climate law can be found at the domestic level, but at the international level only varieties of the former (prescriptive) law exist. The important insight offered in this short article is that a fundamental difference exists between international climate law and domestic climate law that goes beyond the difference in prescriptive and incentivizing law and has to do with the logic of the problem of climate change, viz. that the problem cannot be solved except through a collective response.