December 26, 2009 – Original Source: Mongabay
Over the past few weeks the United States has been pounded by a number of big snow storms. A week ago Washington DC received 18 inches of snow, setting a number of records. Over Christmas, the middle of the country, from Texas to Minnesota was also hit by record amounts of snow. While snow fall over the East Coast and middle of the country in the United States in December is hardly unusual, a number of record amounts of precipitation may point to a larger shift in the climate. Scientists say that higher temperatures causes more water evaporation, which increases the chances of heavy precipitation events, such as floods and snowstorms.
Oklahoma City hit a record with 14 inches of snow. Dallas-area received its first snowfall on Christmas Eve since records began in 1898. The snowfall also broke Christmas Eve records for Minnesota’s Twin Cities by over two inches. Twenty-three people were killed so far due to the extreme weather across the middle of the country.
While scientists say that it is not possible to link a single extreme weather-event—such as one record snowfall—directly to climate change, a pattern of increased heavy precipitation is expected due to climate change in the US. According to the NCDC’s Climate Extreme Index (CEI) heavy daily precipitation has been increasing since 1950 in the United States.
Globally, precipitation has increased in regions over 30 degrees north according to the Intergovernmental Panel on Climate Change, but has been declining in tropical regions since the 70s.