The content of international climate change law is being subjected to investigation and critical analysis after twenty years of international policy on climate change. The ila’s Legal Principles Relating to Climate Change are a contribution to this discussion. The ila has put forth a ‘principle of prevention’ as being not just relevant to, but at the very foundation of, climate change law—in particular mitigation law. In their article in this issue of the journal, Schwarte and Frank focus on the ila’s reliance on the prevention principle, endorsing the ila’s approach in this respect. However, as I argue in this comment, the principle of prevention is neither applicable nor of relevance to the problem of climate change, and thus cannot be an element of climate change mitigation law. I also question the ila’s utilization of another legal principle—the precautionary principle—as a basis for the development of an international law of adaptation.