Humanity’s situation with climate change is sometimes compared to that of a frog in a slowly boiling pot of water. Most of our climate science takes the form of prediction: telling the frog that in five minutes’ time he will be a little bit warmer. We need more risk assessment: telling the frog that the worst that could happen is he could boil to death, and that this is becoming increasingly likely over time. This approach can give a much clearer picture of the risks of climate change to human health, food security, and coastal cities.