Why global warming is producing record snowfalls
As Earth gets warmer, large regions will experience heavier rain and snowfall as weather becomes generally more intense. –National Center for Atmospheric Research
Go to original in the The Progress Report
To understand why the current cold snap across the United States 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.”
Why all the snow?
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 (NCAR) found, “As Earth gets warmer, large regions will experience heavier rain and snowfall as weather becomes generally more intense.” The reason for the increase in storm intensity is that as the planet warms, “the temperatures of the atmosphere and of the ocean surface go up as well, leading to increased evaporation and an increased capacity for the air to hold moisture. As this soggy air moves from ocean to land, the storms that form are heavier with rain or snow.”
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. Take for instance the record snowfall that has hit upstate New York. This event would be predicted by the climate models because the “lake effect” snowfalls are greatly influenced by the warm waters of Lake Ontario.
As cold Arctic air moves over the warm waters, the water evaporates and cools, it condenses to form clouds, and the clouds ultimately produce snowfall. The warmer the lake waters, the more snow that will be produced. True to form, the waters on Lake Ontario this year were warmer than usual. “This winter, there’s no way the lake will freeze.” Therefore, a cold snap heightens the chance of heavy snow.
