In a recent New York City conference, less cautious environmentalists claimed that "Global warming and a decline in the quality of the world's ecosystems are increasing illnesses from water-borne organisms and from diseases such as malaria, dengue fever and Lyme disease." Don Melnick, professor of anthropology and biological sciences at Columbia University and organizer of the conference, pointed to an increase in Lyme disease in the northeastern United States, caused by a decrease in the number of predators who stalk deer -- he must have been referring to hunters since non-human predators of deer have not flourished in the Northeast for over a hundred years -- with the result that contact between humans and deer is more common than in the past. The connection between a growth in the deer and human populations in the Northeast and climate change was left unexplained. Perhaps he meant that both thrived under warmer conditions!
In reality, the health of the world's people is improving. Over the last 35 years, the world's death rate has been cut in half. Life expectancy continues to grow to unprecedented levels, and each year infant mortality falls to record lows. Today 86 percent of the world's population lives in a country where newborns enjoy a life expectancy greater than 60 years, compared to six out of ten in 1980. If your parents or grandparents were born in America before the early 1930s, they were not expected to make it to their sixth decade, a rarely reported fact that President Roosevelt leaned on to insure the solvency of Social Security.
Smallpox, a major scourge prior to the 19th century, has been completely eliminated from the world. The last of the virus is slated for execution in 1999. The WHO predicts that polio, which killed millions annually before the development of a vaccine and claimed just over 100,000 worldwide in 1990, can be wiped out by the end of the century. The prevalence of leprosy -- the AIDs of the Middle Ages --has been cut in half in the decade of the 1980s, as has tetanus in infants. River blindness and guinea-worm disease should be eliminated in the next few years. The number of malaria deaths worldwide has dropped since 1990.
There is, of course, much opportunity for improvement. In the poorest countries, well over a hundred of every thousand babies die by the end of their first year, while in the advanced countries, less than 7 per thousand fail to celebrate their first birthday. Nearly one-third of the children under five in the developing countries were underweight. Although 80 percent of the world's children have received vaccines for diphtheria, measles, whooping cough, polio, tetanus and tuberculosis, in some African countries less than half have been immunized.
These problems, which are serious, are related not to climate change but to poverty. Blaming global warming for an increase in malaria and dengue fever in Southeast Asia, as Professor Melnick did, is baseless. A warm climate, like that enjoyed in Southeast Asia, is a necessary condition for the mosquitoes that can carry malaria to flourish; but it is not a sufficient condition for malaria to become endemic. Singapore, which is located just 2 degrees from the Equator, reported no deaths from malaria in 1994. Malaysia, just next door, suffers from endemic malaria and dengue fever. The difference is not the climate but the wealth of the two areas.
Before 1940, malaria was widespread in the southern portions of the United States. Although sporadic cases are still diagnosed north of the Mexican border, brought mostly by travelers from abroad, the likelihood that malaria will again secure a firm foothold in the country is negligible. For a disease spread by mosquitoes to become endemic, a large number of hosts, that is, humans, must carry the parasite. Simple precautions can prevent the spawning of a resident-affected population. If people protect themselves from mosquitoes by using screens on their windows and doors, or, when outside, wear long-sleeved clothing, apply insect repellents containing DEET, and sleep in a screened enclosure or under a mosquito net, the virus cannot secure a foothold.
Environmentalist such as Professor Melnick believe that the world should take action now to head off further warming of the world's climate, at least partly to slow or stop the spread of these diseases. Although the cost of attempting to slow the production of greenhouse gases is rarely discussed, it would be expensive. Estimates by pro-environmental advocates have ranged from 2.5 to 3.5 percent of world GDP or roughly $500 billion to $750 billion annually. But only a small fraction of this sum could do much to alleviate sickness and ill health in poor countries than futile attempts to quell a non-threatening climate change by stifling global productivity throuhg taxation. For example, the WHO estimates the cost of immunizing children against six major killers at $14.60 per child -- a total cost of around $400 million annually to treat the 20 percent of the world's children who now go without immunization. This modest expenditure, less than 0.1 percent of the cost of slowing warming, could save millions of children's lives immediately. Spending resources on slowing the emission of carbon dioxide would do little to retard the spread of disease but would do much to make the world poorer.