DATE: July 16, 2019
SNIP: A peer-reviewed study published this week warns that if we don’t reverse emissions trends quickly and sharply, we will see a rise in unprecedented heat waves that will “break” the National Weather Service’s heat index scale.
The researchers warn we will face extended scorchers more brutal than the United States has ever experienced before. In several decades, parts of Florida and Texas could experience a heat index for five or more months per year exceeding 100 degrees, “with most of these days even surpassing 105 degrees.”
The administration’s own studies confirm this. Typical five-day heat waves in the U.S. will be 12 degrees warmer by mid-century alone, according to the U.S. National Climate Assessment (NCA), which the White House itself reviewed and approved last November.
From the report:
By mid-21st century (2036–2065) under both emissions scenarios, the annual numbers of days with heat indices exceeding 37.8 °C (100 °F) and 40.6 °C (105 °F) are projected to double and triple, respectively, compared to a 1971–2000 baseline. In this timeframe, more than 25% of the US by area would experience no analog conditions an average of once or more annually and the mean duration of the longest extreme heat index event in an average year would be approximately double that of the historical baseline. By late century (2070–2099) with a high emissions scenario, there are four-fold and eight-fold increases from late 20th century conditions in the annual numbers of days with heat indices exceeding 37.8 °C and 40.6 °C, respectively; 63% of the country would experience no analog conditions once or more annually; and extreme heat index events exceeding 37.8 °C would nearly triple in length. These changes amount to four- to 20-fold increases in population exposure from 107 million person-days per year with a heat index above 37.8 °C historically to as high as 2 billion by late century.