Tuesday, January 22, 2013

US: Warmest Year On Record

As many probably know by now, 2012 was the warmest year on record for the contiguous United States.  In fact last year obliterated to previous record.  The record was eclipsed by a full one degree Fahrenheit.  This was an astounding result and is outside any normal experience.  The graphic below illustrates the comparison with the five warmest years on record.

A comparison of the average temperature for the contiguous U.S. with the warmest years on record.  Image Credit: Climate Central.

Every state saw warmer than normal temperatures for the year, however the amount of heat was not uniform.  Record heat was reported in the Southwest, Central U.S., and the Northeast.  It was quite hot in the Southeast, but much of the area escaped the hottest temperatures.  Many of the all-time record high temperatures set during the Dust Bowl era fell in the central U.S. this past summer.

A look at the distribution of heat across the U.S. for 2012.  Image Credit: Climate Central.

This is in keeping with the longer trend in extreme temperatures.  Research has shown that since the 1970s the ratio of high temperatures to low temperatures has been increasing.  The ratio was up to 2:1 by the first decade of this century.  It is interesting that the ratio for 2012 was 5:1 nationally.  The research further estimates that the ratio is likely to be 20:1 by mid-century and if emission of heat-trapping pollution continues on its current trajectory, the ratio will be 50:1 by the end of the century.

The ratio of record high temperatures to record low temperatures by decade.  Image Credit: Climate Central.

How did we fare in South Carolina?  It turns out that the state temperature averaged enough for the fifth hottest year on record.  However, there were some notable events during the year.  Columbia missed setting a record for the year by a few hundreds of a degree, making this only the second hottest year on record.

A comparison of the warmest annual temperatures in Columbia, SC.  Image Credit: Climate Central.

The annual temperature doesn’t begin to tell the whole story.  First, it was the warmest March on record for Columbia.  Then on June 29 Columbia set an all-time record high temperature, breaking the old record that had been tied on six different occasions.  In addition, the new record was tied the very next day.  Furthermore, the humidity was building and on July 1 it was 106 F with a heat index of 119 F that afternoon.

All-time record high temperatures set on June 29, 2012 in Columbia, SC.  Image Credit: WLTX-TV.

It turns out that on June 29, the temperature at the University of South Carolina observing site reached 113 F, breaking the state all-time record high of 111 F.  That reading has been verified and is now the new official all-time record high temperature for South Carolina.