Global Warming and Warm Weather: Connected?

Jan. 6, 2007 — -- It was expected to reach into the 70s today in New York City. Cherry blossoms were blooming in Washington, D.C.

Is there a connection between the January heat wave that is sweeping the East Coast and man-made global warming?

Scientists say yes -- in this way: What they know for sure is the warm winter fits the pattern, exactly, that has long been predicted for manmade global warming of more and more frequent unseasonable warm spells.

While there were freak weather events like this in the past, even before the Industrial Age started pumping out more greenhouse gases, they were rare.

But in recent decades they have increased.

There has been "a fairly rapid rise of globally average temperatures, also temperatures in the United States, since about the mid-1970s," said David Easterling of the National Climate Data Center.

The records from the National Climate Data Center show that over the last 55 years, especially the last 20, the number of unusually warm days and warm nights has steadily increased.

The supercomputers that predicted all this decades ago have grown even more powerful. What do they project for the years immediately ahead, if greenhouse gas emissions are not drastically cut worldwide?

"Over the next two or three decades, we will see a trend of just more frequent warm spells and less frequent cold snaps," said Jerry Meehl, a climatologist.

But these changes are not limited to just warm weather. Colorado's third big snowfall in a month also fits a pattern long predicted for global warming.

The warmer the air, the more moisture it can hold, which leads to heavier precipitation of rain or snow.

Scientists say there are always immediate causes contributing to warm spells, such as the current warm El Nino patch that's appeared again in the Pacific.

But El Nino, like everything in earth's climate, is influenced one way or another by manmade global warming.

Climate scientists in the United Kingdom calculate that the current El Nino, combined with the additional warming effect of the increasing manmade greenhouse gases mean a better-than-even chance that 2007 will be the hottest year on earth since records have been kept.

Already, the 10 hottest years on record have been in the past 11 years.