The US 'Heat Index' Could Be Broken in Upcoming Waves A new study says extremely hot days will <br />become much more common in the near future. In a standard HI chart, heat's effect on humans <br />is measured by the combined air temperature <br />and humidity. According to co-author Kristina Dahl, this is <br />the first analysis to include the heat index <br />in a global warming study. The report adds that days across <br />the U.S. where the index pushes <br />past 100 degrees will soon double. 30 years from now, <br />hundreds of U.S. cities<br />may see over a month's worth <br />of these high temperatures. On some days, it may become so hot that <br />the index will <br />be "incalculable." Co-author and climate analyst <br />Erika Spanger-Siegfried says these kinds of conditions could be "deadly" for humans. Erika Spanger-Siegfried, via study Erika Spanger-Siegfried, via study
