It is very disappointing that this article has not a word about any disagreement surrounding the health and related consequences of global warming, let alone of any disputes about its very likelihood.

Tibor R. Machan
Orange, Calif.

The article asserts that malaria and other tropical diseases will migrate northward with global warming. This ignores the fact that malaria was common in many parts of the United States 100 years ago but is now virtually unknown, even in south Florida. Also, there were several major epidemics of yellow fever in midlatitude American cities back then. Malaria and yellow fever, like plague, typhoid, and cholera, are basically social, not climatic, afflictions.

Douglas Lilly
Kearney, Neb.

In the typical “correct science” harangue of today, all the possible bad effects are emphasized (deadly summer heat waves), none of the possible good effects are even mentioned (CO2 is a primary plant food), and nothing at all is hinted about the state of computer models used to predict such “imminent” (100 years hence) cataclysms. I say shame on Science News .

Owen W. Dykema
Roseburg, Ore.

Although carbon dioxide indeed has a fertilizing effect on plants, many studies have found that that effect often doesn’t last because the soil soon becomes exhausted of other nutrients. Also, one long-term study of rice yields in the Philippines suggests that a temperature increase of just 1°C will reduce harvests by as much as 10 percent (SN: 7/10/04, p. 29: Warmer climate, decreased rice yield) .—S. Perkins