Last Year Wasn’t Just Hot – It Was a Habanero: Chart

Source: NOAA's National Climatic Data Center. The warmest 5 years are highlighed in orange: 1998, 2006, 1934, 1999 and 1921. The coolest 5 years are in blue: 1903, 1924, 1895, 1912 and 1917.

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Source: NOAA's National Climatic Data Center. The warmest 5 years are highlighed in orange: 1998, 2006, 1934, 1999 and 1921. The coolest 5 years are in blue: 1903, 1924, 1895, 1912 and 1917.

To say that 2012 was hot is an understatement. The average temperature in the contiguous U.S. last year was 55.3 degrees Fahrenheit, 3.2 degrees hotter than the 20th century average and 1 degree hotter than the previous record. 

One degree may not sound sound like much, but the chart above, by NOAA's National Climatic Data Center, shows just what a big deal it really is. Each line displays year-to-date temperature anomalies, going back to 1895. Significant deviations from the average temperature are rare; a small fraction of a degree separates each year. Just 0.2 degree separates the previous record average temperature holder -- 54.3 degrees in 1998 -- from the one before that, 1934.

Last year’s departure from the normal temperature exceeded the previous record's by 29 percent. It’s as if a baseball player smashed Barry Bonds’s juiced-up 73 home-run record with 102 homers in a single season. It’s as if Exxon Mobil’s $45.2 billion profit in 2008 were surpassed by a company raking in $63.3 billion. If last year’s weather were edible, it would make habanero peppers taste mild. 

The effects of such a hot year were widespread and are still ongoing. Each of the lower 48 states had above-average temperatures for the year. Forty-five states recorded one of their top-ten hottest years; 19 set records. 

The heat contributed to the worst U.S. drought since the 1930s, which ravaged corn and soybean crops and drove commodity prices to records. Wildfires consumed more than 9 million acres. The Mississippi River, which typically carries about $7 billion in goods in December and January, has dwindled so low it may be forced to shut down by the end of next week

While last year was extreme, it wasn’t unexpected. Extreme weather like heat waves and intense precipitation are increasing globally and are projected to become ever more common this century, according to the  Intergovernmental Panel on Climate Change. That’s not to say that every year will be a warm one, but the likelihood of extreme extremes has increased. 

“The heat we saw in the U.S. is consistent with what we expect in a warming world,” Deke Arndt, chief of the climate monitoring branch at NOAA's center, said on a conference call. “It’s a huge exclamation point on the end of several decades.”

Analyses and commentary on The Grid are the views of the author and do not necessarily reflect the views of Bloomberg News. 

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