2012 hottest year on record in continental US, second most extreme

First Posted: Jan 10, 2013 11:48 AM EST

It is official: The year 2012 was the warmest and second most extreme year on record for the contiguous U.S. according to the National Oceanic and Atmospheric Administration's (NOAA) National Climatic Data Center.

And 2012 didn't just barely break the heat record, but by a significant margin: The average temperature for 2012 was was 55.3°F, which is 1.0°F higher than in 1998, the previous warmest year, and even 3.2°F above the 20th century average, calculated NOAA. Epic droughts and disastrous storms in the U.S. were in the headlines around the world, being a global event, which also moved agricultural commodity prices on world markets.

Indeed, the average precipitation total for the contiguous U.S. for 2012 was 26.57 inches, 2.57 inches below average, making it the 15th driest year on record for the nation. At its peak in July, the drought of 2012 engulfed 61% of the nation with the Mountain West, Great Plains, and Midwest experiencing the most intense drought conditions.

Each season of 2012 had precipitation totals below the 20th century average. Winter brought below-average precipitation to both coasts and above-average precipitation to the Southern Plains, slightly lessening drought conditions that plagued the region in 2011. The winter precipitation total was 89% of normal.

The NOAA also compiles what it calls the U.S. Climate Extremes index, and 2012 was the second most extreme year on record for the nation. The index, which evaluates extremes in temperature and precipitation, as well as landfalling tropical cyclones, was nearly twice the average value and second only to 1998. There have been no less than 11 disasters breaching the $1 billion threshold in losses in the U.S. last year, including Sandy, Isaac, and tornado outbreaks experienced in the Great Plains, Texas and Southeast/Ohio Valley.

Every state in the contiguous U.S. had an above-average annual temperature for 2012, according to the NOAA. Nineteen states had a record warm year and an additional 26 states had one of their 10 warmest. The year already started with a surreal heat wave in March - which actually happened in Europe as well. In Alaska though, the year started with record cold temperatures, and it stayed below average for the rest of the year.

The weather extremes experienced in the U.S. and other parts around the world can be related to the broader climate of planet Earth, which is showing tendencies of accelerating change in several regions. Among the findings in 2012 were the shrinking of arctic ice to the lowest level ever recorded, and also stronger warming in the Western Antarctic ice shield than previously known. There are various scenarios of the direction and implications of climate change, based on models calculated with a variety of parameters. A general increase in extreme weather events like temperature spikes and storms is common to several of those scenarios.

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