and coupled it to MIT's integrated global climate model. The resulting model is far less computationally demanding yet is still able to account for urban air pollution. Using their new model, they find that, although there could be noticeable regional effects, global mean temperature should not change much, even if urban air pollution increases markedly over the next 100 years. Their research is reported in the Journal of Geophysical Research—Atmospheres (2000,105 (D18), 22,869-22,896).
Mashing malaria mania Imagine yourself out on your back porch on a hot summer night in Hoboken, NJ. It is July 2010. A mosquito lands on your arm and begins biting you. You quickly brush it away, but not before it has drawn blood. Panic sets in. Malaria! There have been frequent warnings that this is a plausible scenario if the current global warming trend continues. This is not an accurate picture of what is likely to happen, say Dave Rogers and Sarah Randolph of the University of Oxford in England. Using a statistical treatment of data and considering several climatic variables together with the known present-day distribution of Plasmodium falciparum—the parasite that causes the most severe form of malaria, the two researchers predict that the geographical distribution of the disease is unlikely to change much if the world gets hotter as a result of global climate change effects Their report Science (2000 289 1763-1765) In accounting for the difference between their predictions and those of other investigators, the researchers fault the biological transmission models that others have used. They note that most previous modelbased predictions of disease spread arising from global warming have relied on estimates of temperature change alone as the principal driver. Rogers and Randolph instead have built an improved scenario of malaria's northern reach by considering a combination of drivers: temperature precipitation and vapor pressure All of these variables not just temperature alone they argue m u s t b e sidered in forecasting the spread of P. falciparum Combining this information with future global warming s c e n a r i o s leads t h e m t o c o n c l u d e
that even under the most extreme conditions of climate change, few, if any, changes should be seen in the siting of the disease.
Bye-bye birdie? Concerns that genetically modified crops could affect biodiversity have been given new emphasis by a recent farmland study. A. R. Watkinson, of the University of East Anglia, Norwich, along with colleagues from the university, as well as the British Trust for Ornithology in Norfolk, England, suggest that the impact of genetically modified herbicide-tolerant (GMHT) crops on farmland biodiversity could be severe and harm local bird populations. Not everyone, however, agrees that the problem is potentially as serious as it seems In England, commercial introduction of GMHT crops awaits completion of full-scale evaluations of farmland biodiversity effects. To address this issue, Watkinson and colleagues developed a mathematical model to measure the impact of GMHT sugar beet crops on farmland weed populations. The model they devised considers agricultural decision-making practices, weed population dynamics, and regional bird impacts. On the basis of their analysis, the scientists predict that farmland weed populations could be significantly reduced or even eradicated where GMHT crops are grown. Consequences for bird populations could be severe, they argue, because weed seeds are a major food source for several bird species. In a related comment, Les Firbank, of the Centre for Ecology and Hydrology, Cumbria, England, and Frank Forcella, of the U.S. Department of Agriculture's Agricultural Research Station in Morris, MN, suggest that the Watkinson model is a helpful framework for assessing GMHT crop impacts on local bird populations. However, citing the experiences of U.S. extension workers and farmers with growing GMHT maize, soybean, canola and sugar beet crops in the United States they question the claim that "consequent effects on the local use of fields by birds might be severe"
AMERICAN CHEMICAL SOCIETY Science
That M a t t e r s .
One publisher is responsible for 49% of all citations in Chemistry.*
ACS PUBLICATIONS We're just about half-way there.
When you choose journals from the American Chemical Society, you're choosing the highest value and quality for your chemistry collections. Repeatedly ranked in the top rated journals for total citations and impact factors by the ISP Journal of Citation Reports®, ACS journals deliver the information that your clients demand. Based on the ISI® JCR8 1998 Science Ed. for the "Chemistry" subject category
if CJIV^HT crops are introduced
merciallv Firbank and Forcella suggest that both GMHT and non-GMHT systems can he modified to favor biodiversitv Thp two rennrts flnnpar in ^ri
puce (2000 289 1481-1482
ACS PUBLICATIONS High Quallty. High Impact. http://pubs.acs.org
NOVEMBER 1, 2000 / ENVIRONMENTAL SCIENCE & TECHNOLOGY / NEWS » 4 6 1 A
