Quantifying climate deaths

Dr Simon Lewis is a Royal Society research fellow at the Earth and Biosphere Institute, University of Leeds. In a comment in the Guardian (UK), he asks, what is the mortality burden of climate change? It’s not an easy question: …We know that climate change-related events are killing people, yet there is no comprehensive global monitoring program to document the lives lost due to climate change. There is no official climate-change body count.

…The World Heath Organisation publishes the only global estimate of the number killed by climate change - about 150,000 annually. Worryingly, this estimate comes from a single modelling study in 2002, and includes only four impacts of climate change (deaths from one strain of malaria, malnutrition, diarrhoea-type diseases and flooding). It is, as the authors point out, a highly conservative first estimate and, by now, considerably out of date.

Why are we relying on a single, limited, out-of-date study for our information on the numbers of people killed by climate change? This is not a criticism of the WHO; the real question is why they are apparently alone in this effort. The core of the climate-change community, of course, is that group studying the atmosphere. Their questions therefore don't often relate directly to human health. The medical profession is obviously more interested in saving lives now than in the slower and longer term effects of climate change, and so have been late in engaging with the question.

Naturally, funding influences which questions are answered. Politicians have not asked for a body count. But why not? Perhaps there are parallels with another politically charged issue involving widespread mortality, where nobody counted: the war in Iraq. Governments probably do not want to hear about people dying in foreign lands because of their own choices. Who is going to fund comprehensive studies when the headline might read "British carbon emissions responsible for 3,000 deaths last year"?

The precise relationship between greenhouse gas emissions and deaths that both the environmentalists and Judge Cooper wanted information on should not be beyond scientists in the future. Equivalent statements are routinely made by medical specialists, such as the proportion of all stroke deaths attributable to hypertension in a given year, or attributing lung cancer deaths to passive smoking. It is merely a question of deciding whether it is an important question to answer.

Such an understanding is essential for two quite different reasons. First, it is a basic issue of justice. The dead should be remembered and their families and friends should understand the factors involved in their deaths. Second, it seems likely that the numbers of people killed by climate change has been significantly underestimated. This means that, in addition to issues of the morality of equating human lives with the time spent waiting in airport queues, such cost-benefit analyses used to shape government policy with major climatic impacts, such as building a new runway at Heathrow, are likely to be biased by underestimating the cost in human lives of such decisions.

US National Cemetery in Arlington, Virginia, Turelio, Wikimedia Commons