The hottest year in US history and one of the most extreme

The nation suffered through 11 weather-related disasters including a record drought, hurricanes Sandy and Isaac, and the deadly tornado outbreaks in the Great Plains, Texas and the Ohio Valley.

WASHINGTON // Last year was the warmest year on record in the United States and the second-most extreme in terms of climate.

The hot weather contributed to a record drought which, at its peak, parched 61 per cent of the nation, destroyed crops worth billions and slowed shipping on the mighty Mississippi River as water levels reached historic lows.

The dry conditions helped spark massive wildfires that charred 9.2 million acres, the third-highest annual figure on record, the National Oceanic and Atmospheric Administration (NOAA) said.

The nation suffered through 11 weather-related disasters that each caused US$1 billion (Dh3.67bn) or more of damage. They included hurricanes Sandy and Isaac, and the deadly tornado outbreaks in the Great Plains, Texas and the Ohio Valley.

Many scientists warn this is just a taste of what is to come as a result of climate change.

"This disturbing news puts the heat on president [Barack] Obama to take immediate action against carbon pollution," said Shaye Wolf, the climate science director with the Centre for Biological Diversity. "Science tells us that our rapidly warming planet will endure more heatwaves, droughts and extreme weather.

"The president needs to start making full use of the Clean Air Act to fight greenhouse-gas emissions before it's too late."

Sandy was the most destructive disaster last year. It made landfall near New York, killing 131 people, leaving eight million without power and destroying tens of thousands of homes and businesses.

Mr Obama signed a bill on Sunday approving $9.7bn in emergency disaster aid for victims of the superstorm, which is just a fraction of the $60.4bn package the White House is seeking.

Last year was the third year in a row in which there were 19 named tropical storms, 10 of which reached hurricane strength. One was a major hurricane.

All 48 states in the continental US had above-average annual temperatures and 19 of them broke records. The average temperature for 2012 was 12.9°C, 1.78°C above the 20th century average.

The warm temperatures meant winter "was nearly non-existent for much of the eastern half of the nation," NOAA said. Many areas had near-record low snowfalls, which left soil parched.

The US Climate Extremes Index, which evaluates extremes in temperature and precipitation along with tropical storms that make landfall, was nearly twice the average value and second only to 1998.