The Fifth Annual Brilliant 10

David Thompson, 36


Arctic El Nino Discoverer

His identification of a key northern weather pattern pulled climate science into the stratosphere

David Thompson was still in his 20s, a graduate student at the University of Washington, when he helped discover a phenomenon that would radically alter the way climatologists understand northern weather patterns. Thompson and his adviser, atmospheric scientist John M. Wallace, were the first to identify the extent of a climate system that engulfs the top third of the planet. This Arctic Oscillation (AO), as they called it, changes weather patterns all over the hemisphere, from blizzards in Cleveland, to rainfall in Spain, to the frequency of the Eastern seaboard´s dreaded Nor´easters. Call it El Nio of the North.

Swirling counterclockwise from a latitude of 55 degrees north-about parallel with Moscow and Ketchikan, Alaska-the AO can shift from its negative phase (when its ring of wind blows more slowly and is easily thrown off course, causing cold Arctic air to spill out into the midlatitudes) to its positive phase (when winds are strong, holding in the cold air) as frequently as every few days. But over time, trends emerge. The positive cycles associated with warmer winters, for instance, dominated much of the 1980s and 1990s

The discovery of the AO had a near-immediate influence on many fields of climate study, notably among climate-change experts who suspect that emissions may be responsible for pushing the AO to remain in the positive phase for longer periods of time. Meanwhile Thompson, now a professor at Colorado State University, turned his focus south, where cooling over parts of Antarctica has been held up by global-warming skeptics as evidence that the world is not, in fact, heating up. In 2001 Thompson and Susan Solomon of the National Oceanic and Atmospheric Administration offered a more likely explanation for the temperature aberration: the ozone hole. That huge void in the atmosphere, they found, shifted wind patterns over Antarctic in a way that cooled its surface-except, tellingly, over the Antarctic peninsula, the glaciers of which have been calving into the Southern Ocean at alarming rates.

What ties Thompson´s global
work together is an obsession with
the importance of the upper atmo-sphere. â€What happens down here comes back down,†he says. â€The tail does wag the dog.â€-Kalee Thompson