Pushing Rope: :: A Lesson: The Difference between Climate & Weather ::

For all you global warming or climate change skeptics/naysayers out there, or for those of you who would like to understand the difference, CAP has provided a great and simple explanation that bears reposting:

Earlier this month, the Intergovernmental Panel on Climate Change released a report that confirmed and refined what scientists already knew: The recent global warming trend is real, it is caused primarily by human activities, and we can expect further dangerous warming of a few degrees if we don't reduce our emissions of greenhouse gases. Despite the very high level of confidence that the IPCC placed on this assertion, climate skeptics refuse to allow themselves to be convinced by the facts. Global warming deniers--desperate for any information that might contravene the science--have latched onto this month's colder-than-normal temperatures that have gripped much of the U.S., particularly the northeast and mid-Atlantic regions. In fact, the temperature patterns we are currently experiencing are exactly what increasing greenhouse gas emissions predicts: climate destabilization.
Weather and climate are two distinct and separate concepts. To understand why the current cold snap across the U.S. is occurring during a global warming trend, one must first understand the distinction between climate and weather. Climate is the "composite or generally prevailing weather conditions of a region, as temperature, air pressure, humidity, precipitation, sunshine, cloudiness, and winds, throughout the year, averaged over a series of years." In other words, climate refers to recorded history. Weather, on the hand, is current events; it refers to the "state of the atmosphere at a given time and place." Weather is a snapshot of the climate at any one instant. Although the two are related, their relationship is indirect. "The chaotic nature of weather means that no conclusion about climate can ever be drawn from a single data point, hot or cold. The temperature of one place at one time...says nothing about climate, much less climate change, much less global climate change."

The current trend of snowfall across the country is consistent with the increased precipitation expected to occur with a warming globe. Scientists have said "snowfall is often predicted to increase in many regions in response to anthropogenic [human-induced] climate change, since warmer air, all other things being equal, holds more moisture, and therefore, the potential for greater amounts of precipitation whatever form that precipitation takes." Based on computer models, a recent study by the National Center for Atmospheric Research found, "As Earth gets warmer, large regions will experience heavier rain and snowfall as weather becomes generally more intense." The NCAR climate models have predicted that heavier rains and/or snow would most likely affect regions where large masses of air converge, including northwestern and northeastern North America.

Around the globe, the existence of a warming trend is clear. The long-trend trends present clear evidence that climate change is "real and serious." The IPCC report noted that the "the warmth of the last half century is unusual in at least the previous 1300 years." Of the 12 hottest years on record, 11 have occurred since 1995. The 2006 average annual temperature for the contiguous U.S. was the warmest on record and nearly identical to the record set in 1998, according to scientists at the National Oceanic & Atmospheric Administration's National Climatic Data Center. Residents of the Washington, D.C. metropolitan area have this week been hit by a "gusty wintry wallop" and are experiencing below-average temperatures for this month. Yet, the deviation below the average temperature for February is still less than the above-average deviation that D.C. residents experienced during the month of January. While the climate change trend is clear, the weather patterns at different moments in time will be hard to predict.