Climate Change Will Expose Millions of People in U.S. to 'Off-the-Charts' Extreme Heat

Authored by newsweek.com and submitted by Wagamaga

In the coming decades, climate change will lead to a significant increase in the frequency and severity of dangerous extreme heat across the contiguous United States, the Union of Concerned Scientists (UCS) has warned.

The organization has conducted an analysis of current heat trends to make predictions about the future climate for a new report and accompanying study published in the journal Environmental Research Communications.

According to the research, climate change will lead to a spike in the number of days per year when the heat index—or "feels like" temperature—exceeds 100 and 105 degrees Fahrenheit, unless drastic action is taken to curb greenhouse gas emissions.

By the middle of the century, the team predict that there will be an average of 36 days in the contiguous states where the heat index will exceed 100 degrees—around double historical baseline levels. This figure will increase to 54 by the latter part of the century.

Meanwhile, the number of days where the heat index exceeds 105 degrees is estimated to increase more than four-fold to 24 by mid-century. And by late century this figure will rise to 40.

In fact, the analysis suggests that there will be few areas of the country that will escape these extreme heat events, save for some high-altitude mountainous regions.

"Our analysis shows a hotter future that's hard to imagine today," Kristina Dahl, senior climate scientist at UCS and co-author of the report, said in a statement. "Nearly everywhere, people will experience more days of dangerous heat even in the next few decades."

"By the end of the century, with no action to reduce global emissions, parts of Florida and Texas would experience the equivalent of at least five months per year on average when the 'feels like' temperature exceeds 100 degrees Fahrenheit, with most of these days even surpassing 105 degrees," she said. "On some days, conditions would be so extreme that they exceed the upper limit of the National Weather Service heat-index scale and a heat index would be incalculable. Such conditions could pose unprecedented health risks."

Currently, the only place that experiences these "off-the-charts" days—when the heat index is 127 degrees Fahrenheit or higher—is the Sonoran Desert on the border of southern California and Arizona.

Because this area is sparsely populated, only about 2,000 people are exposed to these extreme days for a week or more every year on average. But worryingly, the researchers predict that this figure will rise to about 6 million people by midcentury and 118 million by late century as "off-the-chart" days become more common across the country.

"We have little to no experience with 'off-the-charts' heat in the U.S.," Erika Spanger-Siegfried, lead climate analyst at UCS and co-author of the report, said in a statement. "These conditions occur at or above a heat index of 127 degrees, depending on temperature and humidity. Exposure to conditions in that range makes it difficult for human bodies to cool themselves and could be deadly."

2bad2care on July 16th, 2019 at 22:10 UTC »

No one will really care until the power grid becomes overtaxed and they need to start weathering these heatwaves without air conditioning.

Edit: Thanks for the gold.

nashsmash on July 16th, 2019 at 21:42 UTC »

I live in Phoenix so I can't image how hot it will get here.

thenewsreviewonline on July 16th, 2019 at 20:44 UTC »

By late century (2070–2099), large portions of the Gulf Coasts states—including Texas, Louisiana, Mississippi, Alabama, and Florida—are projected to experience 120 days per year or more above 100 °F (37.8 °C) while more limited areas in Texas and south Florida are projected to experience 150 or more days per year above 105 °F (40.6 °C).

Areas with minimal exposure to 100 °F or 105 °F conditions either historically or by midcentury, such as the Pacific Northwest and northern New England, are projected to experience 10 to 20 days above 100 °F and up to 10 days above 100 °F per year by late century (2070–2099).

Link: https://iopscience.iop.org/article/10.1088/2515-7620/ab27cf

EDIT: It should be noted that the temperatures refer to the heat index. Heat index combines air temperature and relative humidity to give a ‘feels like’ temperature.