LAS VEGAS – A new study suggests consecutive days with extreme heat in Nevada will skyrocket if nothing is done to rein in global warming.

“Our analysis shows a hotter future that’s hard to imagine today,” study co-author Kristina Dahl, a climate scientist at the Union of Concerned Scientists, said in a statement to USA TODAY. “Nearly everywhere, people will experience more days of dangerous heat in the next few decades."

By 2050, hundreds of U.S. cities could see an entire month each year with heat index temperatures above 100 degrees The heat index is what the temperature feels like to the human body when relative humidity is combined with the air temperature. This is the first study to take the heat index – instead of just temperature – into account when determining the impacts of global warming, Dahl said.

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The number of days per year when the heat index exceeds 100 degrees will more than double nationally, according to the study, which was published Tuesday in the peer-reviewed journal Environmental Research Communications.

In the Southwest, residents could see an average of 35 days per year with a heat index above 100 degrees, 22 days per year with a heat index above 105 degrees – and 10 “off-the-charts” days per year by the end of the century if no action is taken to reduce global warming emissions.

"Off-the-charts" translates how it sounds: Conditions that exceed the National Weather Service's heat index range – effectively breaking the index itself and presenting mortal danger to people.

A sweltering southwest

Alongside Arizona, California and New Mexico, Nevada would see some of the largest rises in extreme heat.

Historically, there have been 12 days per year on average in Nevada with a heat index above 90 degrees. That number could jump to 39 days per year by midcentury and 68 by century’s end, according to the study.

In Las Vegas, projections are more acute.

Historically, there have been 99 days per year in Southern Nevada with a heat index above 90 degrees. By century’s end, that number could hit 150.

When it comes to days above 100, the average could leap from 71 days per year at the midcentury mark to 96 by the year 2100.

In Reno, the historical average for a heat index above 90 degrees stands at 7 days per year – a number that could hit 72 by the end of the century.

What's the solution?

The report provides a troublesome portrait of Southern Nevada's future – one that could include a week or more of "off-the-charts" heat days that break the index, according to the study.

So what is there to do about it?

"Rapidly reduce global warming emissions and help communities prepare for the extreme heat that is already inevitable,” report co-author Astrid Caldas told USA TODAY. “Extreme heat is one of the climate change impacts most responsive to emissions reductions, making it possible to limit how extreme our hotter future becomes for today’s children.”