United States May See Extreme Changes In Climate Within 50 Years
December 18, 2012

Supercomputers Used To Help Predict Future Extreme Climate Changes In The US

April Flowers for redOrbit.com - Your Universe Online

With the recent history of extreme droughts and super storms, many are wondering what the future holds for the climate of the eastern United States. New research from the University of Tennessee, Knoxville, has taken the guesswork out of it.

The results of this study, published in a recent issue of Environmental Research Letters, show that the region will be hotter and wetter in the future.

The research team consisting of Joshua Fu, a civil and environmental engineering professor, and Yang Gao, a graduate research assistant created a "climate crystal ball," a set of precise scales of cities that predict high-resolution climate changes almost 50 years into the future.

The researchers combined high-resolution topography, land use information and climate modeling using the power of UT's Kraken and Oak Ridge National Laboratory's (ORNL) Jaguar, now called the Titan, which is the fastest supercomputer in the world. They used dynamic downscaling — which allowed the researchers to develop climate scales as small as four square kilometers — to develop climate model results.

"Instead of studying regions, which is not useful when examining extreme weather, dynamical downscaling allows us to study small areas such as cities with a fine resolution," said Fu, who is also a professor within the UT-ORNL Bredesen Center for Interdisciplinary Research and Graduate Education.

Fu and Gao evaluated extreme events along with daily maximum and minimum temperatures and daily precipitation for 23 states east of the Mississippi River. The team analyzed the current climate from 2001 to 2004, which allowed them to predict the climate from 2057 to 2059. The findings of this study are the first to predict heat waves for the top 20 cities in the eastern U.S. The study predicts, for example, that Nashville will see a temperature rise of 3.21 degrees Celsius while Memphis temperatures will rise 2.18 degrees Celsius.

The team found that heat waves would become more severe throughout the eastern portion of the country by comparing present climate to future predictions, with the Northeast and Midwest experiencing a greater increase in heat waves than the Southeast. The Southeast will almost equalize the temperatures between the future North and current South according to the model.

"Currently, the mean heat wave duration is about four days in the Northeast and eastern Midwest and five days in the Southeast," said Fu. "By the end of the 2050s, the Northeast and eastern Midwest will be gaining on the Southeast by increasing two days."

The study reveals that the Northeast and eastern Midwest are likely to suffer from steeper increases in the severity of heat waves.

"While the Southeast has the highest intensity in heat waves, the northeast is likely to experience the highest increase," said Fu. "We are looking at temperature increases of 3 to 5 degrees Celsius, with New York experiencing the highest hike."

An increase of precipitation of 35 percent or more will be felt by both the Northeast and Southeast, with most coastal states seeing the greatest increase of about 150 millimeters a year. The Northeast shows the largest increases in precipitation, taking into consideration heat waves and extreme precipitation, suggesting a greater risk of flooding.

"It is important that the nation take actions to mitigate the impact of climate change in the next several decades," said Fu. "These changes not only cost money–about a billion a year in the U.S.–but they also cost lives."