Report: 'Killer heat' coming to Cannon County
Tuesday, July 16, 2019 4:00 am WASHINGTON -- Increases in potentially lethal heat driven by climate change will affect every state in the contiguous U.S. in the decades ahead, according to a new report and accompanying peer-reviewed study in Environmental Research Communications, both by the Union of Concerned Scientists, released today. Few places would be unaffected by extreme heat conditions by midcentury and only a few mountainous regions would remain extreme heat refuges by the century's end. Without global action to reduce heat-trapping emissions, the number of days per year when the heat index--or "feels like" temperature--exceeds 100 degrees Fahrenheit would more than double from historical levels to an average of 36 across the country by midcentury and increase four-fold to an average of 54 by late century. The average number of days per year nationwide with a heat index above 105 degrees Fahrenheit would more than quadruple to 24 by midcentury and increase eight-fold to 40 by late century. According to the report, Cannon County historically (1971-2000) averages 6 days per year with temperatures above 100 degrees. The report predicts by the middle of this century (2036-2065), unless bold action is taken now to address the climate crisis, the average number of days of temperatures over 100 will increase to 54 per year. That number would increase to 87 days per year from 2070 to 2099 unless action is taken, the report states. However, if "bold action" is taken, the average number of days with temperatures over 100 in Cannon County could be limited to 40 per year. The "no action scenario" assumes carbon emissions continue to rise and the global average temperature increases nearly 4.3 degrees Celsius (about 8 degrees Fahrenheit) above pre-industrial levels by century's end. The "slow action scenario" assumes carbon emissions start declining at midcentury and the global average temperature rises 2.4 degrees Celsius (4.3 degrees Fahrenheit) by century's end. In the "rapid action scenario," global average warming is limited to 2 degrees Celsius (3.6 degrees Fahrenheit)--in line with the Paris Agreement. The analysis also examined the number of people in each state that would be exposed to a heat index above 90 degrees Fahrenheit, 100 degrees Fahrenheit, 105 degrees Fahrenheit, or off-the-charts conditions for an average equivalent of at least one week, one month, or two months per year. All population data presented here, including for future projections, is based on the most recent U.S. Census conducted in 2010 and does not account for population growth or changes in distribution. The U.S. Southeast region, as defined by the latest U.S. National Climate Assessment, would be the hardest hit seeing an average of 96 days per year with a heat index above 100 degrees Fahrenheit, 73 days per year with a heat index above 105 degrees Fahrenheit and 12 "off-the-charts" days per year by the end of the century if no action is taken to reduce global warming emissions, with Florida, Louisiana and Mississippi seeing the largest rise in extreme heat. The sobering results for all Southeast states, assuming no global action to reduce emissions, are below. Tennessee Historically, there have been 51 days per year on average with a heat index above 90 degrees Fahrenheit, the worker safety threshold. This would increase to 100 days per year on average by midcentury and 128 by the century's end. Historically, there have been eight days per year on average with a heat index above 100 degrees Fahrenheit. This would increase to 53 days per year on average by midcentury and 84 by the century's end. Of the cities with a population of 50,000 or more in the state, Clarksville, Jackson and Memphis would experience the highest frequency of these days. Limiting warming to 2 degrees Celsius above pre-industrial levels would cap the frequency of such days at an average of 40 per year. By the end of the century, an estimated 6.1 million people would be exposed to a heat index above 100 degrees Fahrenheit for the equivalent of two months or more per year. By limiting warming to 2 degrees Celsius, more than 4.9 million of those residents would avoid such days of extreme conditions. Historically, there has been an average of two days per year with a heat index above 105 degrees Fahrenheit. This would increase to 32 days per year on average by midcentury and 63 by the century's end. Limiting warming to 2 degrees Celsius above pre-industrial levels would cap the frequency of such days at an average of 21 per year. By the end of the century, an estimated 6.3 million people would be exposed to a heat index above 105 degrees Fahrenheit for the equivalent of a month or more per year. By limiting warming to 2 degrees Celsius, nearly 4.6 million of those residents would avoid such days of extreme conditions. Historically, the state as a whole has experienced zero "off-the-charts" heat days in an average year. This would increase to two days per year on average by midcentury and 11 by the end of the century. Limiting warming to 2 degrees Celsius could cap the frequency of such days at an average of one per year. By the end of the century, an estimated 5 million people would endure "off-the-charts" heat days for the equivalent of a week or more per year. Historically, fewer than 2,000 people nationwide have experienced such conditions in an average year. By limiting warming to 2 degrees Celsius, all residents could avoid such days of extreme conditions. The Union of Concerned Scientists puts rigorous, independent science to work to solve our planet's most pressing problems. Joining with people across the country, we combine technical analysis and effective advocacy to create innovative, practical solutions for a healthy, safe, and sustainable future. For more information, go to www.ucsusa.org.
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