A team led by UCLA geographers has found that lakes in the wilderness of Siberia are shrinking or vanishing—findings that contradict past research on climate change.

Global warming appears to be causing lakes to drain and disappear in Arctic regions, a UCLA-headed team of researchers has found.

If the pattern persists, it may imperil migratory birds and disrupt the region's weather, cautioned Laurence Smith, the study's lead author and an associate professor of geography at UCLA.

Along with geography department chair Glen MacDonald and researchers from the State University of New York in Syracuse and the University of Alaska, Smith tracked changes in more than 10,000 large lakes by examining satellite imagery taken between 1973 and 1998 across the Siberian wilderness.

In the study funded by the National Science Foundation, the team found that the total number of lakes larger than 100 acres decreased from 10,882 to 9,712, a decline of 11 percent. Most lakes did not disappear altogether, but instead shrank to sizes less than 100 acres. However, 125 lakes vanished completely and became covered with vegetation.

The findings run counter to past climate change research, which has tended to show that Arctic warming results in the increase of bodies of water as the icy permafrost layer melts like an ice cube, forming ponds.

"We were totally surprised by our findings," Smith said. "We were expecting the lake area to have grown with climate change."

Arctic weather patterns have become a closely watched field in recent years because the region's climate is changing at a much faster pace than that of the rest of the globe.

What causes the disappearing lakes? The team points to the thawing of the permafrost layer. But unlike the theories formed during earlier research, the current findings focus on thawing of the water-tight permafrost layer along lake bottoms.

"Most of these lakes are laying on top of permanently frozen ground, a surface that prevents lake water from draining into the ground," Smith said. "We think that climate warming is thawing the permafrost. When that occurs, it's like pulling the plug out of a bathtub—there's nothing to prevent lake water from percolating through the soil to aquifers below.

"The process appears to be abrupt and irregular," Smith said. "From what we can tell from space, a lake is either just fine or it's gone."