Joughin has published a study showing this effect in one East Antarctica area, but NASA studies of other coastal areas show a very different phenomenon. In West Antarctica, especially, research has shown that ocean warming has caused an increase in the glaciers' speeds. In those areas, the warmer ocean temperatures have led to faster bottom melting of the glaciers along the edges of the ice sheets. The greater the bottom melting, the faster the glaciers flow. And the faster they flow, the more water they transfer from the frozen continent into the ocean.

"We've seen this," Davis says of the phenomenon. "The Antarctic peninsula has warmed by about two degrees Fahrenheit in the last 50 years. A couple of the ice shelves [permanent layers of ice that are connected to the continent but float on the ocean] have completely disintegrated. All the glaciers that had been feeding those shelves have sped up and are discharging into the ocean at a much greater rate." Some researchers suspect this phenomenon, called "ocean forcing," is occurring along much of Antarctica's coastline. More data will be needed to determine whether they're right.

Such additional research has both important implications for Davis' snow theory and for our understanding of global warming in general. Right now, for instance, it looks like the thickening of East Antarctica's interior nearly balances the seawater contributions of West Antarctica's melting ice sheets. But that reassuring assessment will likely change as scientists gather more data from the continent's coastal regions.

NASA is aiming to accelerate the learning curve by launching more satellites. In the meantime, Davis and his colleagues are working to develop new ways of understanding the data they already have. "We're going to have to take different approaches," Davis says. "When we add all of [the lines of investigation] together, we have hope that certainly in the next 10 years -- and maybe in the next five -- we'll have [a full picture]. We have so much more information now than we did five years ago."

Davis is also quick to point out that Antarctica's ice is just one part of a complex dynamic, and that a better understanding of its place in the sea level puzzle will open doors to other avenues of inquiry. The Greenland ice sheet, non-polar glaciers, thermal expansion of oceans, changes in ground water levels and variations in the volume of ocean basins each also play a part in determining how much water fills the Earth's oceans.

This is not to suggest, however, that Davis isn't sold on what he's doing. "We're working hard ... on measuring the various pieces of what's contributing to present-day sea level rise," Davis says. "That's the first step. If we want to predict what's going on in the future, we had better understand what's going on right now."

Published by the Office of Research.

©2006 Curators of the University of Missouri. Click here to contact the editor.