Megadrought Possible in the US Southwest (and Global Warming is to Blame)
A new study published in the Journal of Climate Science suggests that the risk of a “decade-scale megadrought” in the US Southwest is above 80% and may be as high as 90% in specific areas. Even worse, the risk of a longer event, lasting more than 35 years, is between 20% and 50%, and the risk of a half-century drought (under the most extreme global warming circumstances) is between 5% and 10%. The study is based on the projected changes in rainfall patterns that are likely to change the ecosystems and water supplies over the next hundred years. This data examines what other global climate models do not: that the largest hydroclimatic fluctuations are more apparent as trends over decades or even centuries, and less inter-annually.
It is worth noting that the study applies only to precipitation in that it does not incorporate the increase in evaporation of water that accompanies warming temperatures- this means that the true level of risk may exceed the percentages above. The data is also based on the most severe warming scenario, RCP8.5. Representative Concentration Pathways (RCP) are four different greenhouse gas concentration scenarios (RCP2.6, RCP4.5, RCP6, RCP8.5) named for the relative amount of radiative forcing projected for the year 2100 as compared to data prior to the Industrial Revolution. The four values are measured in watts per square meter. Radiative forcing is the difference between sunlight absorbed by the earth and the amount of sunlight radiated back into space. RCP8.5 is the only scenario of the four that assumes emissions continue to rise through the remainder of this century, the other three scenarios assume a peak followed by a decline. RCP8.5 is kind of the do-nothing scenario where humankind keeps on keeping on without taking steps to mitigate our climatic impact.
According to the US Drought Monitor, over 58% of California is experiencing an “Exceptional Drought.” Global Warming is real; we are starting to feel the effects of it and things are only going to get worse if we continue pumping crap into our thin little atmosphere.
Additional Source: Study author Toby R. Ault published more information and graphics from the study about the megadrought on Cornell University’s website.
The image is of a South Dakota farm during the Dust Bowl. “Dust Bowl – Dallas, South Dakota 1936” by Sloan (?) – United States Department of Agriculture; Image Number: 00di0971 (original link now dead). Licensed under Public domain via Wikimedia Commons.