| 摘要 | Today, the Senate Health, Education, Labor and Pensions Committee will hold a hearing on the implications of climate change for human health. Malaria will top the menu, but so will ignorance and disinformation.
The lead witness will be Dr. Jonathan Patz of the University of Wisconsin, Madison. He has suggested that U.S. energy policy may be “indirectly exporting diseases to other parts of the world.” Dr. Patz, the World Health Organization (WHO) and others claim that global warming is now spreading disease and may be the cause of some 160,000 deaths a year.
In 2007, for example, WHO pointed to rising temperatures in an outbreak of a mosquito-borne virus, Chikungunya, in Italy. Yet WHO misdiagnosed the problem. Modern transportation, not climate change, caused the outbreak.
In that case, the transmitter of the disease, or vector, was the Asian Tiger mosquito. It is native to Asia, but exported world-wide in shipments of used tires. It is now abundant in parts of U.S. and in 12 countries in Europe. In cities, it breeds in man-made 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, where an epidemic of the disease was then raging.
So the real technological villain in that case was the jet airplane. 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.” And it was absurd for environmental alarmists to chime in with apocalyptic pronouncements.
The globalization 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 likely arrived in the U.S. in shipments of wild birds. These diseases are spread by mosquitoes and therefore difficult to quarantine.
It may come as a surprise that malaria was once common in most of Europe and North America. In parts of England, mortality from “the ague” was comparable to that in sub-Saharan Africa today. William Shakespeare was born at the start of the especially cold period that climatologists call the “Little Ice Age,” yet he was aware enough of the ravages of the disease to mention it in eight of his plays.
Malaria disappeared from much of Western Europe during the second half of the 19th century. Changes in agriculture, living conditions and a drop in the price of quinine, a cure still used today, all helped eradicate it. However, in some regions it persisted until the insecticide DDT wiped it out. Temperate Holland was not certified malaria-free by the WHO until 1970.
The concept of malaria as a “tropical” infection is nonsense. It is a disease of the poor. Alarmists in the richest countries peddle the notion that the increase in malaria in poor countries is due to global warming and that this will eventually cause malaria to spread to areas that were “previously malaria free.” That’s a misrepresentation of the facts and disingenuous when packaged with opposition to the cheapest and best insecticide to combat malaria–DDT.
It is true that malaria has been increasing at an alarming rate in parts of Africa and elsewhere in the world. Scientists ascribe this increase to many factors, including population growth, deforestation, rice cultivation in previously uncultivated upland marshes, clustering of populations around these marshes, and large numbers of people who have fled their homes because of civil strife. The evolution of drug-resistant parasites and insecticide-resistant mosquitoes, and the cessation of mosquito-control operations are also factors.
Of course, temperature is a factor in the transmission of mosquito-borne diseases, and future incidence may be affected if the world’s climate continues to warm. But throughout history the most critical factors in the spread or eradication of disease has been human behavior (shifting population centers, changing farming methods and the like) and living standards. Poverty has been and remains the world’s greatest killer.
Serious 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. The alarmists will likely steal the show on Capitol Hill today. But anyone truly worried about malaria in impoverished countries would do well to focus on improving human living conditions, not the weather.
Roger Bate is a resident fellow at AEI. Paul Reiter is the director of the Insects and Infectious Diseases Unit of the Institut Pasteur, Paris. |
