The peak of the snowmelt season, a heavy mountain snowpack and an exceptionally wet spring have all combined to produce the highest flow in the South Platte River that Colorado has seen in many years while, across the Great Plains, deep winter snows and heavy spring rains have created an unusually verdant landscape. At the same time, severe drought persists in parts of the northern plains and southern California and Lake Superior is at its lowest level in decades, reflecting a regional dirth of rain and snow over the past few years. While Tropical Storm Barry brought some relief to the parched landscape of the Southeastern States, the region's annual precipitation remains well below normal.
Such regional, cyclic weather patterns are distinct from climate change. The latter is a slow, steady change in the weather of a region, continent or the planet as a whole, resulting from long term changes in ocean currents, atmospheric conditions or even the location of the continents; for example, parts of Antarctica enjoyed a tropical climate before it drifted to the South Pole. On a smaller scale, a changing ocean current may enhance or diminish the precipitation along a coastal region; over thousands of years, this could lead to the development of a rain forest or a treeless desert, respectively.
Encouraged by a zealous media, the public often associates our transient weather patterns with global warming, the hot topic of the decade. While there is no doubt that our global climate is warming (and that humans likely play a significant role in that process), regional weather aberrations are not related to that phenomenon. But the presumed association makes good headlines!
