Paul Reiter

The inconvenient truth about malaria

Al Gore has made bold claims that climate change is aiding the spread of insect-borne diseases. The science does not support him, says Paul Reiter

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Al Gore’s film, An Inconvenient Truth, was a masterpiece. Like an elder brother to all humanity, he patiently explained the familiar litany of disasters — droughts, floods, hurricanes, sea-level rise and the rest — spiced with heartrending personal stories: his baby son’s near-fatal accident, the agony of losing a sister to lung cancer. It was a science lecture crafted by Hollywood.

In his book — the version for adults, not the one for schoolchildren — he even included a colour photograph of a corpse, a young man, floating face downward, drowned by Hurricane Katrina. I wonder whether the dead boy’s family were consulted.

I am a scientist, not a climatologist, so I don’t dabble in climatology. My speciality is the epidemiology of mosquito-borne diseases. As the film began, I knew Mr Gore would get to mosquitoes: they’re a favourite with climate-change activists. When he got to them, it was all I feared.

In his serious voice, Mr Gore presented a nifty animation, a band of little mosquitoes fluttering their way up the slopes of a snow-capped mountain, and he repeated the old line: Nairobi used to be ‘above the mosquito line, the limit at which mosquitoes can survive, but now…’ Those little mosquitoes kept climbing.

The truth? Nairobi means ‘the place of cool waters’ in the Masai language. The town grew up around a camp, set up in 1899 during the construction of a railway, the famous ‘Lunatic Express’. There certainly was water there — and mosquitoes. From the start, the place was plagued with malaria, so much so that a few years later doctors tried to have the whole town moved to a healthier place. By 1927, the disease had become such a plague in the ‘White Highlands’ that £40,000 (equivalent to about £350,000 today) was earmarked for malaria control. The authorities understood the root of the problem: forest clearance had created the perfect breeding places for mosquitoes. The disease was present as high as 2,500m above sea level; the mosquitoes were observed at 3,000m. And Nairobi? 1,680m.

These details are not science. They require no study. They are history. But for activists, they are an inconvenient truth, so they ignore them. Even if Mr Gore is innocent, his advisers are not. They have been spouting the same nonsense for more than a decade. As scientists, we have repeatedly challenged them in the scientific press, at meetings and in news articles, and we have been ignored.

In 2004, nine of us published an appeal in the Lancet: ‘Malaria and climate change: a call for accuracy’. Clearly, Mr Gore didn’t read it. In 2000, I protested when Scientific American published a major article loaded with the usual misrepresentations. And when I watched his animated mosquitoes, his snow-capped mountain was oddly familiar. It took a few moments to click: the images were virtually identical to those in the magazine. The author of the article, Dr Paul Epstein, features high in Gore’s credits.

Dr Epstein is a member of a small band dedicated to a cause. And their work gains legitimacy, not by scholarship, but by repetition. While they publish their work in highly regarded journals, they don’t write research papers but opinion pieces and reviews, with little or no reference to the mainstream of science. The same claims, the same names; only the order of authors change. I have counted 48 separate pieces by just eight activists. They are myth-makers. And all have been lead authors and/or contributory authors of the prestigious IPCC assessment reports.

Take their contention, for example, that as a result of climate change, tropical diseases will move to temperate regions and malaria will come to Britain. If they bothered to learn about the subject, they would know that in a period climatologists call the Little Ice Age, when Charles II held ice parties on the Thames, malaria — ‘the ague’ — was rampant in the Essex marshes, on a par even with regions in Africa today. In the 18th century, the great systematist Linnaeus wrote his doctorate on malaria in central Sweden. In 1922-23 a massive epidemic swept the Soviet Union as far north as Archangel, on the Arctic circle, killing an estimated 600,000 people. And malaria was only eliminated from the Soviet Union and large areas of Europe in the 1950s, after the advent of DDT. So it’s hardly a tropical disease. And yet when we put this information under the noses of the activists it is ignored: ours is the inconvenient truth.

The activists also claim that malaria is already increasing in sub-Saharan Africa because of climate change, and that the people who are attacked by our climatic transgressions are those least able to defend themselves.

Science has a different angle. In the first place, malaria in most of sub-Saharan Africa is ‘stable’: everyone gets bitten by infective mosquitoes every year, sometimes as many as 300 times. So it is absurd to claim that climate change will increase the rate of infection; you cannot add water to a glass that’s already full.

On the other hand, in regions where malaria is newly arrived, or has emerged after a period of remission, a plethora of interacting factors are at play, including forest clearance, irrigation, the mobility of people, urbanisation, resistance to insecticides and antimalarial drugs, the Aids epidemic, population increase, the degradation of public health infrastructures, and war and civil strife. Most of all: poverty. Poverty and malaria go hand in hand. There is no evidence or need to implicate temperature.

When the Bush government nominated me as a lead author for the Intergovernmental Panel on Climate Change (IPCC), I knew I hadn’t a snowball’s chance of being accepted. The IPCC, supposedly formed of thousands of the world’s top scientists, is an ‘Intergovernmental’ panel. Governments nominate the authors, governments make their selections from those nominations, and governments must approve of all reports, line by line, before they are published. Moreover, the IPCC is a UN organisation, so its ‘top scientists’ are drawn from the 192 member countries of the UN Framework Convention on Climate Change. Each chapter must include two authors from developing countries and at least one from an emerging economy. Clearly, the people of the Maldives are not going to nominate a scientist like me, but if they did, I doubt the project would get very far: the IPCC Working Group II, based in Exeter, somehow happened to lose my nomination from their database. 

At the end of his movie, Al Gore ridicules global warming ‘sceptics’ as a tiny and dwindling band of flat-earthers, people who believe the moon landings were staged, and accuses us of being richly rewarded by the oil industry. According to him, ‘the science is in’. End of discussion.

In truth, the science is never in. We’re not pollsters or policy-makers. We proceed by question, observation, hypothesis, and testing by experiment. We are still re-testing Einstein’s theory of relativity! So I’m happy to be a sceptic. That is how science works.