Past Winner
1997 E.W.R. Steacie Memorial Fellowship

Andrew Weaver

Earth and Ocean Sciences

University of Victoria

When most of us think about the climate, we think about what's happening in the atmosphere. Dr. Andrew Weaver has a different perspective on climate - he looks at the ocean. The University of Victoria oceanography professor has an international reputation in climate modeling, especially the development and use of coupled ocean-atmosphere models. His achievements have recently earned him one of Canada's premier science and engineering prizes - a Steacie Fellowship awarded by the Natural Sciences and Engineering Research Council.

"I use the models to understand the role of the ocean in climate change," explains Weaver. "One of my interests is how mechanisms of variability in the ocean affect the natural variability in climate. If we don't understand this natural variability, we have no hope of finding the signal for global warming when we look at the data."

Having a good model of the ocean-atmosphere system is critical to understanding and predicting climate change. An important part of Weaver's research is running his models to see how well they agree with the data that exist for past climates. For example, his group has studied the transition from the last glaciation, about 18,000 years ago, to the present day climate. About 11,000 years ago, there was a sudden return to glacial-like conditions in the Northern Hemisphere for about 1000 years.

Why did this happen? Weaver suggests that as the ice sheets melted they dumped freshwater into the Atlantic Ocean, shutting down the North Atlantic conveyor, the ocean conveyor that transports heat from south to north. As a result the north got cold again.

"One of the most remarkable things about the climate record is evidence that climate change occurs abruptly," says Weaver. "The change to a colder climate 11,000 years ago happened over the course of a few decades."

Could similar events happen again? One of the possible effects of global warming is enhanced evaporation at low latitudes and increased precipitation at high latitudes. The result could be more freshwater flowing into the North Atlantic, paradoxically creating local cooling there initially.

About one half of Weaver's research involves running the models, the other half is devoted to improving them. "For me, the real excitement comes from running the models myself - getting in there and getting my hands dirty," he says. "I love the uncertainty. There's nothing better than an experiment that doesn't work the way you thought it would. That's when you find the really interesting things."