As I write this, an air conditioning repairman is on his way to my house as the fan broke a couple of days ago. Normally at this time of year we could wait to get it fixed, but it’s going to be dangerously hot today. It’s October 2, and temperatures are expected to reach at least 96°F today in Washington, D.C., with an even higher heat index—a record high for this date, and possibly for October, in the nation’s capital. And we’re not alone.
This unseasonable heat is hanging over much of the country, with 162 communities or more facing potentially record highs this week. Wilmington, Ohio’s National Weather Forecast issued a statement today that heat indices in the region are projected to soar into the mid-to-upper 90s, twenty-five to thirty degrees above average. South Central, Indiana, and Central Kentucky’s local weather forecast office put out a hazardous weather outlook warning residents of unseasonable heat and drought, creating a risk of wildfires.
In Baltimore, public schools without air conditioning units are closed. And for the second day in a row, Columbus, Ohio closed the more than 100 schools in its system due to the soaring heat index and lack of air conditioning. Not only are those high temperatures dangerous to children’s health, studies correlate elevated temperatures with reduced student performance (e.g. lower test scores).
And it’s not just on land—sea surface temperatures are also above average across much of the North Atlantic at the moment, fueling tropical storms like Lorenzo which broke the record for a category 5 hurricane this far north and east in the Atlantic.
Extreme heat in the future
A vital takeaway from this autumn heat wave is that, for hundreds of cities and towns, this kind of heat is projected to become standard throughout the warm season and into the fall as a result of climate change, assuming we remain on our current path. In our Killer Heat study that we released in July, we looked at projections of the heat index (the combination of temperature and humidity also known as the “feels like” temperature) for the lower 48 and found that all cities see increases in 90 degree days, and that a great many are projected to become unrecognizably hot if we do not take action to reduce our global warming emissions now.
Take Atlanta. This city, no stranger to heat, could break its record for days over 90 degrees Fahrenheit (90 days in a single year) if the next few days hit that mark as they are predicted to. But what’s important to bear in mind is that our analysis forecasts Atlanta to experience 90 degree temperatures on average 104 times every year by mid-century, making this year’s extreme-heat outlier the norm in just a few decades.
And in Columbus, Ohio, where schools are closed today, 90-degree days should be expected on average 65 times each year by mid-century, and extreme heat days that could spill into the school year with greater frequency. By late century, the city would see more than three months’ worth of such conditions in an average year if we do not take action on climate change.
With air conditioners costing US households about $29 billion annually, the prospect of a much hotter future looks not only dangerous, but costly. That threat requires us to act to reduce heat-trapping emissions both to curtail the growth in extreme heat and to limit the accompanying harm and costs.
As I walked into the office today, I passed a man standing outside chatting who said, “I love the fall, so this is killing me.” I agree.