Does the Heat Wave Confirm Climate Change? Yes and No

(July 7) -- With record-breaking summer temperatures from Beijing to Baghdad to Boston, many people are wondering whether the searing heat is a direct result of global warming.

Most every climatologist will tell you that you can't extrapolate a long-term climate trend from a single weather event or finite period. So, even though the current heat wave gripping much of the world has been rewriting the record books, it may not really tell us all that much about climate change.

Indeed, in attempting to quell climate-change skeptics following a period of heavy snow this past winter, Obama administration scientist Jane Lubchenco stated, "It is important that people recognize that weather is not the same thing as climate."

On its website, NASA further distinguishes the difference between weather and climate:

The difference between weather and climate is a measure of time. Weather is what conditions of the atmosphere are over a short period of time, and climate is how the atmosphere "behaves" over relatively long periods of time.

On the other hand, weather is itself a variable that is at least partially a result of an overall climate, as Anthony Leiserowitz, director of the Yale Project on Climate Change, told The Christian Science Monitor.

"You can't say any one heat wave is caused by global warming," Leiserowitz said. "But you can say that what global warming does is make events just like this more likely."

The 2010 heat wave is not the first to elicit theories about a link to overall climate change. A study published in the journal Nature posited that global warming was partially responsible for the deadly heat wave that scorched Europe in 2003.

Another study, published in 2009 study by the National Center for Atmospheric Research, seems to back up Leiserowitz's assertion while explaining the seeming preponderance of heat waves over the past decades. It shows that since 1950s the United States has seen a greater number of record high temperatures than record lows.

The trend is by no means limited to the United States, however.

"Eleven of the hottest years in history have been in the last 12," Australian Climate Minister Penny Wong told the Australian Broadcasting Corp. in 2009. "And we also note, particularly in the southern part of Australia, we're seeing less rainfall. All of this is consistent with climate change, and all of this is consistent with what scientists told us would happen."

So, while assessing climate change requires that one consider long-term data, perhaps a look at that data also confirms what the mercury in our thermometers is telling us this summer. Then again, it sure was a snowy winter.

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