The Mercer Effect

Twenty years ago climatologist James Hansen of NASA's Goddard Institute of Space Studies, widely considered to be the world's leading authority on global warming, first brought the issue into the public spotlight in testimony before the U.S. Congress. Recently, Hansen published an article entitled "Climate Catastrophe" in the New Scientist (July 28, 2007), http://www.newscientist.com. There he presented evidence suggesting that under "business as usual," in which greenhouse gas emissions continue to increase unchecked, a rise in sea level by several meters during the present century due to the melting of polar ice sheets is a "near certainty."

A sea level rise of this extent (up to five meters or sixteen feet) would mean the loss of land areas on which much of the earth's population lives at present (10 percent of the world's population live less than ten meters above the mid-tide sea level.). Yet, most scientists, even glaciologists, still downplay the full extent of the danger, failing to acknowledge probable nonlinear processes associated with climate change, and are especially reticent when it comes to making public statements in that regard.

Why? Hansen calls this the "John Mercer effect." In the 1970s John Mercer, a glaciologist at Ohio State University's Institute of Polar Studies, drew attention to the West Antarctic Ice Sheet, which is separated from the bulk of Antarctica by a mountain range. Ice shelves floating on its rim put it in a delicate balance so that global warming, Mercer claimed, could within a mere forty years cause it to disintegrate and slide into the sea, raising the sea level by five meters.

Other glaciologists looked into Mercer's model and decided based on the data collected that what he described could indeed happen. But most climatologists and geologists publicly dismissed the idea that an ice sheet as big as Mexico could disintegrate in less than a few centuries (Spencer R. Weart, The Discovery of Global Warming, pp. 79-80). According to Hansen, although it was not obvious at the time whether Mercer or his critics were correct, "researchers who suggested that his paper was alarmist were regarded as more authoritative." Hansen believes that Mercer lost funding opportunities as a result. This discouraged other scientists from speaking out.

The John Mercer Effect then stands for the fact that scientists (in this case glaciologists) are wary of being similarly characterized as alarmists, particularly because of the impact that this may have on future funding. "Scientists downplaying the dangers of climate change [or other threats to the status quo] fare better when it comes to getting funding." Hansen points to his own experience. In 1981, based on the first reliable estimates of average global temperature by NASA, he pointed to the dangers of global warming from fossil fuel use. The result: his research group had some of its funding pulled by the Department of Energy, which specifically criticized aspects of that paper. Hansen argues that such economic/funding constraints have the effect of inhibiting scientific criticisms of the status quo: "I believe there is pressure on scientists to be conservative." To be sure, scientists are trained to be skeptics, but "excessive caution also holds dangers. 'Scientific reticence' can hinder communication with the public about the dangers of global warming. We may rue reticence if it means no action is taken until it is too late to prevent future disasters."

Hansen's description of the John Mercer Effect reflects the way in which a system devoted to what Rachel Carson called "the gods of profit and production" (see the Review of the Month in this issue) constrains scientists (along with everyone else), whenever issues arise that potentially threaten the vested interests-even when it is a question of protecting human life and the planetary environment. In the United States, where so much of the scientific funding comes from the Pentagon and the large corporations, the John Mercer Effect is especially strong in limiting what scientists are willing to say and do. As Richard Levins and Richard Lewontin have written "the irrationalities of a scientifically sophisticated world come not from failure of intelligence but from the persistence of capitalism, which as a by-product also aborts human intelligence" (Dialectical Biologist, p. 208; see also their Biology Under the Influence [Monthly Review Press, 2007]).