The Desert Research Institute's 1999 Nevada Medal will be awarded to Dr. Wallace S. Broecker, a geochemist who has tied the global transport of heat energy by ocean currents to abrupt shifts of the Earth's climate. Broecker (pronounced brĒ!ker) is Newberry Professor of Geology at Columbia University's Lamont-Doherty Earth Observatory and was awarded the National Medal of Science in 1996.
The twelfth internationally prominent scientist to receive DRI's Nevada Medal, Broecker will formally accept the minted medallion and $10,000 prize, underwritten by the shareholders of Nevada Bell, at award dinners in Reno and Las Vegas March 23rd and 25th.
He will present the 1999 Nevada Medal Lecture, "Surprises in the Greenhouse?"on the Reno and Las Vegas campuses of the University of Nevada prior to the award dinners. The talk concerns the potential of increasing greenhouse gases to influence the global "ocean heat conveyor," possibly resulting in abrupt shifts in climate.
"The climate system is an angry beast, and we are poking it," says Broecker. He says that evidence from ice cores and rapidly accumulating sediments points to brief, but dramatic "flickers" in global temperatures as the Earth system switches from one of its modes of operation to another.
His analyses of these abrupt climate shifts suggest that modest increases in global temperatures due to "greenhouse warming" could result in similar dramatic changes. Specifically, Broecker is concerned that polar warming and increased polar precipitation could reduce the density of surface waters and thus modify or even halt the global transport of heat from warm to cold regions of the planet.
Broecker has calculated that deep ocean currents, flowing with a volume of 100 Amazon Rivers, provide nearly a third as much heat energy to the North Atlantic as it receives directly from the sun.
"Imagine London and Dublin with the same climate as the island of Spitsbergen located 600 miles north of the Arctic Circle," says Broecker. "Were the ongoing increase in atmospheric CO2 levels to trigger another such reorganization, it would be bad news for a world striving to feed 10 or so billion people."
Broecker has a Nevada connection going back to the beginning of his professional career: his Ph.D. dissertation included research on the age of the shorelines of ancient Lake Lahontan in north central Nevada.