Last year was the warmest on records going back to 1895 for the 48 contiguous US states and the second-worst for weather extremes including drought, hurricanes and wildfires, according to a US report.
The average temperature in the region in 2012 was 55.3 degrees Fahrenheit (12.9 Celsius), 3.2 degrees higher than the average for the 20th century, the National Oceanic and Atmospheric Administration’s Climatic Data Centre said today in an analysis of the year.
According to the US Climate Extremes Index, which takes into account temperatures as well as tropical storms and drought, 2012 followed 1998 into the record books for extreme weather with almost twice the average value. Eleven disasters caused at least $1 billion in damage, including hurricanes Isaac in August and Sandy in October, the centre said.
The 2012 heat surpassed 1998’s record by 1 degree, a significant amount considering that only 4 degrees separate 1998 from the coldest year on record, 1917, said Jake Crouch, a climate scientist at the Asheville, North Carolina, centre. The warmth is a reflection of natural variability as well as the impact of climate change, he said.
Each of the lower 48 states had an annual temperature that was higher than average, said the center. Nineteen set records.
“I’m afraid it’s just the new normal,” said Robert Marshall, founder of Earth Networks in Germantown, Maryland. “At the end of the day, the trend is pretty clear.”
Last summer had the third-highest population-weighted cooling demand since 1950, Mark Russo, a meteorologist for Chesapeake Energy Corp., said during a presentation today at the annual meeting of the American Meteorological Society.
The 30-year average for cooling-degree days for the months of June, July and August is 1,156, while the 10-year average is 1,208 and the five year average is 1,246, a trend that indicates summers have been getting warmer, Russo said. Cooling-degree days are an indication of weather-related demand for electricity.
Extreme temperatures also added to the drought that choked shipping on the Mississppi, Missouri and Ohio rivers as channels got shallower, limiting loads.
The year was the 15th driest on record, the worst since 1988, with total precipitation of 26.6 inches (67.6 centimeters), 2.6 inches below average. For Nebraska and Wyoming, 2012 was the driest year ever.
The extent of last year’s drought was “roughly equal” to that of the 1950s, although both were smaller than the Dust Bowl of the 1930s, according to the centre.
“The current drought has yet to reach the intensity or duration of the 1950s and 1930s national-scale droughts,” the centre said.
More than 9 million acres were consumed by wildfires in 2012, placing the year third in records going back 13 years. Tornado activity was lower than the average for 1991-2010 and the year may have had the fewest twisters since 2002 with a final count lower than 1,000, the centre said.
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