news Climate change expert stirs new controversy Paul Smaglik, Washington Opponents of the Kyoto Protocol on cli- mate change have found fresh ammunition

in the shape of a new scientific paper. The FRANK SPOONER controversial article suggests that gases other than carbon dioxide are mainly to blame for the rapid global warming seen over the past few decades. The Kyoto Protocol aims to reduce global warming by cutting CO2 emissions, mainly from the use of fossil fuels. But the paper, from a team led by James Hansen of the Goddard Institute for Space Studies in New York, proposes that reducing emissions of methane, soot and the gases that cause photochemical smogs would be the easiest way to limit climate change in the short term. Other climatologists have questioned the assumptions on which Hansen’s conclusions are based, and note that the paper, published last week in Proceedings of the National Acad- Heating up: would reducing the methane emitted by rice fields make an impact on global warming? emy of Sciences (97, 9875–9880; 2000), has not been subjected to formal peer review. efficiency, could help meet his predictions. need for action by developing countries. Hansen helped alert the world to global Michael MacCracken, director of the “Although the paper doesn’t say so explicitly, warming in 1988, warning the US Congress: National Assessment Coordination Office of it seems to shift the burden away from the “It is time to stop waffling… the greenhouse the US Global Change Research Program, West,” says MacCracken. effect is here.” Not surprisingly, his latest agrees that targeting methane and soot could But some US government advisers stress work has been greeted with glee by the Glob- help stem global warming — at least in the that limiting CO2 — for which the United al Climate Coalition, a Washington-based short term. But he takes issue with Hansen’s States is the biggest polluter — remains industry body that is lobbying against US assumptions about fossil-fuel burning. Mea- important. “Reminding everybody that par- ratification of the Kyoto Protocol. Its website sures to clean up industrial emissions by ticles and non-CO2 greenhouse gases are concludes that “too much emphasis has been removing sulphur would reduce cooling by important is fine,” says John Holdren, a spe- placed on the effects of burning fossil fuels”. aerosols, but leave the warming effect of CO2 cialist on environmental policy at Harvard Hansen’s modelling assumes that levels unaffected, MacCracken notes. University, who chairs a panel that advises of CO2 in the atmosphere will continue to In stressing the importance of reducing President Bill Clinton on energy issues. “But increase at a rate of 1.5 parts per million per methane emissions, for which rice cultiva- it’s all too easy to get the impression from the year. He also calculates that tiny particles tion is a major source, and of soot, Hansen’s article that CO2 is not as important as has entering the atmosphere as a result of fossil- paper also puts fresh emphasis on the been thought, and that is not correct.” I fuel burning — in particular aerosols of sul- phates — have a cooling effect that is largely counterbalancing the warming caused by

CO2. Given this, Hansen argues that mea- sures to limit global warming should focus US grant glues ‘virtual cell’ together on pollutants giving rise to ozone in the atmosphere. Paul Smaglik, Washington experiments in protein–protein interaction, But Hansen’s assumptions are controver- The US National Institutes of Health (NIH) and 250 ‘members’ who will specialize in sial. First, population growth and industrial- this week launched a new series of grants compiling protein data and posting them on ization in the developing world mean that for large-scale collaborative projects by websites.

CO2 emissions could grow. “I think it’s actu- pledging $25 million over five years towards The alliance will initially screen for ally very difficult to keep CO2 growth rates to the construction of a ‘virtual cell’. single protein–protein interactions, then Hansen’s targets,” says Tom Wigley of the The first ever ‘glue grant’ — so-called build models of complete signalling National Center for Atmospheric Research because it aims to link research between networks once every element has been in Boulder, Colorado. different institutions — has been awarded to characterized. “We’d really like to represent Second, huge uncertainty surrounds the the Alliance for Cellular Signaling (AFCS), a these pathways completely,” says Gilman. size of the cooling effects of sulphates and consortium based at the University of Texas The five-year project will actually cost other aerosols (see News Feature, pages Southwestern Medical Center and headed by $50 million. Gilman is raising the other half 10–12). Most climatologists say that, in the Al Gilman, professor of pharmacology there. from pharmaceutical companies and non- absence of better data, we cannot assume The AFCS was formed last year to draw profit research organizations. The grant to that aerosols will offset the warming influ- up a complete map of the interactions the AFCS is one of several massive ence of CO2. between one thousand proteins in two types collaborative projects the NIH intends to Hansen argues that population growth of mouse cell (see Nature 402, 219; 1999). launch during the next fiscal year that are and industrialization do not pose insur- It links 50 investigators, who will provide intended to “facilitate the next evolutionary mountable problems. He says that renewable planning and data analysis, seven stage of integrative biomedical science”. I energy, and policies encouraging energy laboratories devoted to conducting ± http://afcs.swmed.edu © 2000 Macmillan Magazines Ltd NATURE | VOL 407 | 7 SEPTEMBER 2000 | www.nature.com 7