A cloudy issue. A new study headed by CAS Associate Professor of Geography Jeffrey Key and BU graduate students will investigate the role of the Antarctic's cloud cover in global warming and the retention of carbon dioxide in the Earth's atmosphere.

Normally, clouds cool the earth below by blocking solar energy (radiation) from reaching the ground, Key explains. Clouds also emit their own radiant energy toward the surface. At night, clouds have a warming effect because they emit more radiation toward the surface than a cloud-free sky does.

However, Key and his research team of graduate students Yufang Jin and Adeline Wong have found that clouds over the Earth's polar regions -- the Arctic and the Antarctic -- have an overall warming, rather than cooling, effect.

"This is in part due to the properties of polar clouds and in part because darkness prevails for six months of the year," Key explains. "During the long winter night, clouds warm the surface by emitting their radiant energy towards the Earth, and during the brief summer they are cooling it."

In the Arctic, the clouds are sometimes warm and sometimes cool. The team's early work has shown that in Antarctica, however, clouds have a measurable net warming effect, which team members attribute primarily to that continent's much brighter snow surface.

Key's research has implications for the Earth's changing climate. "Some scientists believe increasing the cloud cover on a global scale may to some degree offset the warming effect of increased carbon dioxide emissions," he says. "But in the polar regions, we now feel an increase in cloud cover may reinforce the carbon dioxide's warming effect." The team is supported by a grant from the National Science Foundation.

Cataloging a scientist's metamorphosis. Research Fellow Gennady Gorelik of the Center for Philosophy and History of Science plans to create a virtual multimedia archive on the scientific community in which Andrei Sakharov, the father of the Soviet hydrogen bomb, lived and worked. Sakharov, who became a human rights advocate, won the 1975 Nobel Prize for peace.

"Scientists grapple with moral and ethical issues daily," Gorelik explains. "This project will contribute to the understanding of the social role of science in the nuclear age and nourish the exploration of the issue of social responsibility of scientists." He is the author of the first biography of the scientist, Andrei Sakharov: Opening a Closed World, soon to be published by W. H. Freeman. An article based on the book appeared in the March 1998 Scientific American.

In Sakharov's early career he was thrice declared a Hero of Socialist Labor by the U.S.S.R. and was one of its preeminent scientists. Later, after realizing the harm from nuclear testing fallout, he was instrumental in the creation of the Limited Test Ban Treaty. Later still, he began to speak and write on human rights and the dangers of thermonuclear war, invoked the wrath of the Soviet government, and spent seven years in exile.

"The archive will present Sakharov in the context of his scientific community and the Nuclear Age," says Gorelik. "Its core will be the 42 oral histories, mainly from Sakharov's colleagues, I gathered for my book.

"Understanding Sakharov in his own milieu is an excellent basis from which to explore the interactions of science, technology, and society, an interplay that was particularly dramatic for atomic physicists in both the U.S. and the former U.S.S.R.," he explains. "Thanks to the fall of the Soviet regime, its previously classified nuclear community now can be examined, to understand science under a totalitarian regime and the professional, moral, and social responsibilities of scientists."

Gorelik envisions the multi-media archive to be on CD-ROM in major research centers, accessible to scholars and students in the history and sociology of science. A guide to the archive will be available also via the Web, where Gorelik's exhibit for the American Institute of Physics can be viewed, at http://www.aip.org/history/sakharov/.