These days it's important to make sure the air conditioner is working.

Human-caused global warming is a big problem and it's going to get worse.

https://www.theguardian.com/us-news/2020/jun/16/climate-deaths-heat-cdc

Charlie Rhodes lived alone on a tree-sparse street with sunburned lawns just outside Phoenix, Arizona. At 61, the army veteran’s main connection to the world was Facebook; often, he posted several times a day. But as a heatwave blanketed the region in June 2016 – leading to temperatures among the highest ever recorded – his posts stopped. Three weeks later, a pile of unopened mail outside his door prompted a call to police.

When officers arrived, they were overcome by the odor of rotting garbage, worsened by the still-searing heat. Inside the home, they found the air conditioner broken and its thermometer reading 99F. Rhodes lay dead in the bedroom, his body decomposing. The cause, his autopsy shows: “Complications of environmental heat exposure.”

Yearly heat-related deaths have more than doubled in Arizona in the last decade to 283. Across the country, heat caused at least 10,000 deaths between 1999 and 2016 – more than hurricanes, tornadoes or floods in most years.

Scientists link the warming planet to a rise in dangerous heat in the US, as well as the spread of infectious diseases and other health conditions. Federal research predicts heatstroke and similar illnesses will claim tens of thousands of American lives each year by the end of the century. Already, higher temperatures pose lethal risks: the five warmest years nationwide have all occurred since 2006. In the last six decades, the number of annual heatwaves in 50 US cities has, on average, tripled. In contrast to a viral pandemic, this is a quiet, insidious threat with no end point.