That graphic from Climate Central shows the top fifty cities in the United States with the largest percentage increase in intense rain events (comparing the decade 1950-1959 to the ten year period 2005-2014). Those dramatic increases in heavy rainfall are no accident. They are the direct result of anthropogenic climate change. From Scientific American, dated May 27, 2015, “Heaviest Downpours Rise across the U.S.”
Record-breaking rain across Texas and Oklahoma this week caused widespread flooding, the likes of which the region has rarely, if ever, seen. For seven locations there, May 2015 has seen the most rain of any month ever recorded, with five days to go and the rain still coming. While rainfall in the region is consistent with the emerging El Niño, the unprecedented amounts suggest a possible climate change signal, where a warming atmosphere becomes more saturated with water vapor and capable of previously unimagined downpours.
Several people have been killed and hundreds have been rescued from their homes. Texas Gov. Greg Abbott has already declared disaster areas in 37 counties. These torrential downpours follow weeks of unusually rainy weather across the Southern Plains. And they stack up to a broader trend in the region, and across the U.S., toward more heavy precipitation.
Across most of the country, the heaviest downpours are happening more frequently, delivering a deluge in place of what would have been routine heavy rain. Climate Central’s new analysis of 65 years of rainfall records at thousands of stations nationwide found that 40 of the lower 48 states have seen an overall increase in heavy downpours since 1950.
Gosh, makes you wonder who could have predicted such a state of affairs? Oh right, there was ONE group of people who did. From the 2007 Report by the Intergovernmental Panel on Climate Change (IPCC), Working Group I: The Physical Science Basis, FAQ 10.1
Summer dryness indicates a greater risk of drought. Along with the risk of drying, there is an increased chance of intense precipitation and flooding due to the greater water-holding capacity of a warmer atmosphere. This has already been observed and is projected to continue because in a warmer world, precipitation tends to be concentrated into more intense events, with longer periods of little precipitation in between. Therefore, intense and heavy downpours would be interspersed with longer relatively dry periods. Another aspect of these projected changes is that wet extremes are projected to become more severe in many areas where mean precipitation is expected to increase, and dry extremes are projected to become more severe in areas where mean precipitation is projected to decrease.
Dear Climate Change Denialists (including just about every Republican candidate for the 2016 Republican Presidential Nomination, but especially Jeb Bush), please proceed.