The prestigious journal Nature in May published a major report showing that climate change is not a significant cause of malaria--in apparent opposition to numerous alarmists who have been claiming that malaria growth has been caused by climate change. The Economist picked up on it as well.
Paul Reiter, who is quoted in the Nature article, and I testified on the topic back in April 2008. We made some of the same points. At the time there was much furore with the US Senate Health, Education, Labor and Pensions Committee hearing implicating climate change as a cause of worsening human health--perhaps responsible for as many as 160,000 extra deaths a year.
In 2007, for example, the World Health Organization (WHO) pointed to rising temperatures as a cause of the outbreak of a mosquito-borne virus, Chikungunya, in Italy. Yet the WHO misdiagnosed the problem. Modern transportation, not climate change, caused the outbreak.
In that case, the transmitter of the disease was the Asian Tiger mosquito. It is native to Asia, but exported worldwide in shipments of used tyres. It is now abundant in parts of the USA and Europe. In cities, it breeds in manmade containers of water, such as saucers under flower-pots, water barrels, blocked gutters and so on. The virus was carried to Italy by an infected Indian who flew from Delhi.
So the real technological villain in that case was the aeroplane. It was irresponsible, then, for WHO to state 'although it is not possible to say whether the outbreak was caused by climate change . . . conditions in Italy are now suitable for the Tiger mosquito'.
The globalisation of vectors and pathogens is a serious problem. But it is not new. The Yellow Fever mosquito and virus were imported into North America from Africa during the slave trade. The dengue virus is distributed throughout the tropics and regularly jumps continents inside air passengers. West Nile virus is likely to have arrived in the USA in shipments of wild birds. These diseases are spread by mosquitoes and therefore difficult to quarantine.
Malaria disappeared from much of Western Europe during the second half of the nineteenth century. Changes in agriculture, living conditions and a drop in the price of quinine all helped eradicate it. However, in some regions it persisted until the insecticide DDT wiped it out. Temperate Holland was not certified malaria-free until 1970.
The concept of malaria as a 'tropical' infection is nonsense. It is a disease of the poor. Alarmists in the richest countries argue that the increase in malaria in poor countries is due to global warming and that malaria will spread to currently malaria-free countries. That is a misrepresentation of the facts and disingenuous when packaged with opposition to the cheapest and best insecticide to combat malaria--DDT.
Malaria rates increased until recently due to population growth and displacement through civil strife; deforestation; rice cultivation in previously uncultivated upland marshes; clustering of populations around these marshes; the evolution of drug-resistant parasites and insecticide-resistant mosquitoes; and the cessation of mosquito-control operations.
Scientists rarely engage in public quarrels. Alarmists are therefore often unopposed in offering simplicity in place of complexity, ideology in place of scientific dialogue and emotion in place of dry perspective. So it is interesting that leading malaria scientists decided to write the Nature article to set the record straight.
Before ClimateGate in 2009, we saw the high-point of climate alarmism. The UK's Department for International Development (DfID) claimed that climate change was a key determinant of the increase in mosquito-borne diseases such as malaria. DfID in particular was claiming that climate change was contributing to malaria spreading to higher ground in Kenya. Several people demanded evidence . . . it did not exist.
Fortunately, the academics writing this paper in Nature have done an important job to establish the truth. But it is cold comfort for those people like Paul Reiter, who have been trying to set the record straight for years and been pilloried for taking on the climate/health establishment.
Roger Bate is the Legatum Fellow in Global Prosperity at AEI.