In April last year, a group of environmentalists shut down E.ON’s coal-fired power station in Ratcliffe-on-Soar, northern England. The goal: to reduce carbon-dioxide emissions and, in their words, “save lives”.
Last week, United Kingdom Judge Morris Cooper presented a judgement accepting there was an “urgent need for drastic action”, but convicted the environmentalists of aggravated trespass, saying their defence that their crime was necessary to save lives could not be substantiated.
In the trial, for which I was an expert witness, crucial questions were: How many people does climate change kill, and for what proportion is the UK responsible? I was surprised to discover that nobody knew.
Scientists such as myself are involved in programmes to measure carbon-dioxide emissions, air temperatures, sea-ice loss and the much more complex effects on birds, rainforest trees and coral reefs. We know that climate-change-related events are killing people, yet there is no comprehensive global monitoring programme to document the lives lost because of climate change. There is no official climate-change body count.
Admittedly, the effect of climate change on human health and mortality is difficult to quantify. There is no comparison group of people not exposed to climate change. Deaths are often due to multiple causes. And while the probability of a particular event occurring under modified climate conditions can be estimated, no single event can be solely attributed to climate change.
The biggest obstacle is the sheer variety of effects it has on health. These include direct effects, such as drowning in floods, and complex indirect effects, such as falling crop yields, which increases malnutrition, and changes in the spread of infectious diseases such as malaria. Furthermore, care must be taken to subtract any positive health effects on climate change, such as the reduced effects of cold weather on health in a warming world.
The World Heath Organisation (WHO) 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 It is, as the authors point out, a highly conservative first estimate and, by now, considerably out of date.
Why are we relying on a single, limited, out-of-date study for our information on the numbers of people killed by climate change?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 it is apparently alone in this effort.
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 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 should not be beyond scientists in the future. 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 number of people killed by climate change has been significantly underestimated. — Â