Cold US Winter Offset by Above-Normal Global Temps

(March 17) -- It might not exactly be a news flash to report that the 2009-10 winter (December through February) was colder than average across the U.S., but it might be surprising to learn that global temperatures were warmer than average during the winter. What that may -- or may not -- mean about global warming is a matter of opinion.

Using 1951-80 as the base period, NASA's Goddard Institute for Space Studies found that the average global temperature was 1.17, 1.58 and 1.64 degrees Fahrenheit warmer than average for the past three months of December through February, respectively. So even while the U.S. was in the proverbial deep freeze, the warmth in other parts of the globe more than compensated for the cold.

(Image courtesy of Remote Sensing Systems)

February is a good example of how this happened. The blue and purple colors on the image above, which were collected via satellite, indicate the extent and degree of cold across the U.S. and parts of Europe (especially Eastern Europe), with the bright purple areas being more than 4 degrees Celsius (more than 7 degrees Fahrenheit) colder than average.

On the other hand, temperatures across much of Canada and the Arctic region, indicated by the bright yellow, were more than 4 degrees Celsius warmer than average. In addition, much of the Southern Hemisphere, during its summer, was warmer than average, indicated by the predominance of red on the lower portion of the map. Overall, it was warmer than the long-term average across the globe.

Although the details were different, it was the same story during December and January: Large parts of the U.S. and Europe were colder than normal, but this was more than balanced by higher than normal temperatures across other parts of the globe.

This data can mean different things to different people, as it relates to the issue of climate change, including:

Cold weather in high-population, media-laden areas doesn't count any more than warm weather in less populous, media-starved areas when talking about global temperatures.
Record-breaking snow and cold can, indeed, occur even while the atmosphere -- in its entirety -- is warming.
Nothing. The data can also be dismissed as being a sample size too small to be of significance. One season might not be enough to make any judgments, just as a 30-year average might not be enough to make a determination about what should be considered "normal."
All of the above.

It's a matter of opinion and, perhaps, what a person wants the data to mean.