USGS finds complex link to floods and CO2

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WASHINGTON, Oct. 25 (UPI) -- Though increased flooding is expected to be a gauge of climate change, U.S. scientists said they don't have a clear picture of the complex relationship.

Scientists at the U.S. Geological Survey reviewed flood conditions at 200 sites across the United States, looking back more than 100 years from 2008.

Robert Hirsch, lead author of a study, published in the Hydrologic Sciences Journal, said there wasn't a clear picture established that would give scientists the information needed to link climate change to future flood conditions.

"Changes in snow packs, frozen ground, soil moisture and storm tracks are all mechanisms that could be altered by greenhouse gas concentrations and possibly change flood behavior," he said in a statement. "As we continue research, we will consider these and other factors in our analyses."

During the last 100 years, only one of four U.S. regions showed a link between levels of carbon dioxide in the atmosphere and the size of floods.

The USGS said this doesn't mean there isn't a link between flooding and greenhouse gas emissions, only that the relationship was complicated.

"The relationship between greenhouse gas concentrations and floods is complex, demonstrating the need for long-term stream flow data to help guide future flood hazard mitigation and water resources planning," said Matthew Larsen, USGS associate director for climate and land use change, in a statement.