Myles Allen, a physicist at the University of Oxford and author of the above quote, suggested a way to do better: use a metric called fraction of attributable risk (FAR) to quantify the effect of climate change. The FAR requires us to know two numbers: p0, the probability of a heat wave like the 2003 heat wave before climate change (e.g., before 1800), and p1, the probability after climate change. For example, if the probability doubles, then we can say that half of the risk is due to climate change. If it triples, then two-thirds of the risk is due to climate change.
