WASHINGTON — Last year broke records for extreme weather in the United States, with 14 events each causing at least a billion dollars in damage, US authorities said on Thursday.
Also, 2011 marked 35 years in a row that global temperatures have been warmer than average, according to data released by the National Oceanic and Atmospheric Administration.
The NOAA report added two events to the previous toll of 12 disasters last year that cost a billion dollars or more -- Tropical Storm Lee which assailed the Gulf Coast in September and a spate of tornadoes, hail and high wind that hit the Midwest in July.
Twenty-one people died due to Tropical Storm Lee and two from the Midwest outbreak.
Kathryn Sullivan, assistant secretary of commerce for environmental observation and prediction and deputy NOAA administrator, described 2011 as an "extraordinary year."
"It was extraordinary regarding major weather and climate disasters in particular in our country, from tornadoes to droughts to floods and extreme storms," she told reporters.
"America endured an unusually large number of extreme events causing damages totaling more than $55 billion dollars."
Sullivan said a series of factors contributed to the high costs of bad weather, including that there are more "people and infrastructure in harm's way."
The US government also has more sophisticated radars, satellites and land-based tools to track weather events than it did in the past.
"NOAA is keeper of the long term climate record for the nation, this year the physical record also indicated a large extent of climate and weather extremes," she added.
Separately, the US space agency NASA announced that 2011 was the ninth warmest year on record since 1880 in global average surface temperature, with nine of the 10 warmest years in history taking place since 2000.
Despite the ocean-cooling influence of the weather phenomenon known as La Nina in the Pacific, the average global temperature last year was 0.92 degrees Fahrenheit (0.51 Celsius) warmer than the mid-20th century baseline.
"We know the planet is absorbing more energy than it is emitting," said NASA Goddard Institute for Space Studies director James Hansen.
"So we are continuing to see a trend toward higher temperatures. Even with the cooling effects of a strong La Nina influence and low solar activity for the past several years, 2011 was one of the 10 warmest years on record."
Hansen said that with the anticipated return of El Nino and a coming increase in solar activity, temperatures are likely to peak further in the coming years.
"It's always dangerous to make predictions about El Nino, but it's safe to say we'll see one in the next three years," Hansen said.
"It won't take a very strong El Nino to push temperatures above 2010," which tied with 2005 as the warmest year on record.