It's Cold Now, but 2010 Was Warmest on Record Globally

(Dec. 16) -- While much of the United States and parts of Europe have been shivering through intense early-season cold, NASA records show that this was the warmest climate year on record.

The NASA statistics indicate that the overall global temperature during the climate year (December 2009 through November 2010) was 1.17 degrees Fahrenheit above the 1951-1980 base period, making it the warmest since records began in 1880.

All-time record heat occurred in 19 nations in 2010 -- the highest number of national all-time records established in a single year.

These statistics do not take into consideration this month's cold across the U.S. and Europe; however, they do include the unusually low temperatures in these same regions during December 2009 and January 2010.

The cold during that time, although impressive, was more than compensated for by higher-than-average temperatures across much of the remainder of the globe last winter and widespread intense heat during the past summer. In fact, much of the region that experienced intense cold last winter (and again to start this cold season) experienced intense heat during the summer months.

The southeastern U.S. followed one of the colder winters on record with the hottest summer on record.

A simplistic reading of what is going on with the planet's climate would be to hold that the current weather in a region is the sole determining factor in whether the climate is warming or cooling worldwide, and that global warming was halted last winter and resumed during the summer, only to be halted again this month.

The climate is more complicated than that.

Changes in climate -- warmer, colder, drier or wetter -- are represented by slowly changing long-term averages, not the natural up-and-down cycles of weather from one season to the next. The amount of data needed to make useful assessments of Earth's climate is greater than what could be taken from a month, season or year for any individual region or even an entire continent.

The concept of global warming is not one in which every winter would be void of snow and cold and every summer is hotter than the previous. Variations resulting from normal weather processes -- such as extreme cold and snow -- would continue even with global warming.

Some of these normal weather phenomena that account for our short-term weather include (but are not limited to) Pacific Ocean temperature changes (including La Nina and El Nino), Atlantic Ocean temperature changes and the Arctic Oscillation.

One of the many challenges for climate scientists is to determine what effect global warming has had, or might have in the future, on those natural processes. This is much more complicated than making a determination based on the weather at any one time -- and much more open to debate.