Droughts and floods have headlined world news for years, but this year weather-related events have broken many records. Drought is ravaging California for the fourth straight year, and now affects Washington State and Oregon. Texas and Oklahoma have been hit by both drought and severe heat waves. In Southeast Asia, Indian temperatures soaring over 100 degrees Fahrenheit have caused more than 2300 deaths, the fifth deadliest heat wave in recorded history. Pakistan has also experienced severe heat waves.
Climate change contributes to these extreme conditions. Meteorologists have long warned that global warming will change precipitation patterns that will lead to heavier storms, increased flooding, prolonged and more intense droughts. According to the United States Environmental Protection Agency (EPA), the rise in temperatures from global warming has caused an increase in the rate of evaporation, which means more precipitation in the form of rain, not snow. On a recent radio interview on WBAI, leading climate scientists from Stanford University, Noah Diffenbaugh and Mark Jacobson, explained that a declining spring snowmelt dramatically impacts the water supply. For example, the Folsom Dam in California, had little inflow the last few years because the snowpack on the Sierra Nevada Mountains has been the worst in a century. About a third of California’s water storage depends on snowpack as a natural reservoir, unlike other regions that rely on concrete or manmade reservoirs to store melted snow water.
As average temperatures have risen, so has rainfall and downpours. The Union of Concerned Scientists tell us this happens because warmer air holds more moisture and when it meets cooler air, “the moisture condenses into tiny droplets that float in the air.” When the droplets become bigger, rain develops. The downpours in Texas made for devastating floods that killed 15 people and left 12 missing. Texas A&M University recently reported that record rainfall in many parts of Texas has significantly raised the amount of freshwater pouring into the Gulf of Mexico – as high as 10 times the normal rate. The report quoted Steve DiMarco, professor of oceanography, saying that “rivers such as the Brazos, Trinity, Colorado and others, currently carry record amounts of water flowing southward to the Gulf. In 2007 the rivers also overflowed, carrying 10 to 20 times the normal seasonal rate of discharge into the Gulf, according to DiMarco. The floods are expected to create huge problems for marine life and commercial fishermen.
