Word: marchant
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...Saar Senior Writers: Michael S. Serrill, James Walsh Associate Editors: William R. Doerner, Barbara Rudolph Staff Writer: Emily Mitchell Contributors: Robert Ball, Marguerite Johnson, Dominique Moisi, Christopher Ogden, Frederick Painton, Michael Walsh Assistant Editors: Tam Martinides Gray (Research Chief), Ariadna Victoria Rainert (Administration), Oscar Chiang, Lois Gilman, Valerie Johanna Marchant, Adrianne Jucius Navon Reporters: Sinting Lai, Lawrence Mondi, Megan Rutherford, Sribala Subramanian Art: Jane Frey (Senior Associate Director); James Elsis (Associate Director); Nomi Silverman (Assistant Art Director); Victoria Nightingale (Designer) Photography: Julia Richer (Associate Editor); Eleanor Taylor, Karen Zakrison (Assistant Editors) Makeup: Eugene F. Coyle (Chief); Alison E. Ruffley, Leonard...
...least several degrees higher than today. Scientists still do not know precisely what caused the warming or how Antarctica responded. One group argues that during this time significant expanses of the White Continent were not merely ice free but covered with low-lying, tundra-type vegetation. But Marchant and his colleagues contend that the vast ice sheet that covers the Antarctic plateau rode out the temperature rise unperturbed...
...mystery that Marchant is grappling with is perhaps the most profound of all. Today Antarctica is synonymous with ice; 98% of its surface is covered by ice. But this was not always the case. Even though the landmass that constitutes Antarctica has occupied a polar position for well over 100 million years, for much of that time it enjoyed a rather pleasant clime. During the Cretaceous Period, for example, areas that today are obscured by ice were covered with forests of conifers and beech, and through them, scientists believe, roamed a variety of animals, including reptiles and dinosaurs...
...than that was needed to put Antarctica in its present deep freeze. Among their favorite candidates: a reduction of heat-trapping greenhouse gases, notably carbon dioxide. Supporting this idea are the provocative data scientists pulled from an ice core taken near the Russian station at Vostok. That ice, notes Marchant, contained bubbles of air that spanned the past 420,000 years, and the carbon dioxide in those bubbles tracked the temperature swings that mark the beginning and end of glacial cycles...
...Marchant has found ice that promises to be more ancient still, as it lies beneath layers of ash that range between 1 million and 8 million years old. Just like the Vostok ice, Marchant's ice contains air bubbles, meaning that it could produce a record of carbon dioxide swings that occurred over this distant and dimly understood interval of time. First, of course, Marchant will have to convince skeptical colleagues that his ice really is that old, that it has not been reworked by geological processes--and this is likely to take some doing. But if that effort proves...