Hot enough for you?

Well, if you live in one of the many US cities where official heat emergencies have been declared, or if you live in California, suffering the worst wildfires in the state's history, the answer is obvious. Extreme heat creates terrible conditions. And for many vulnerable individuals those conditions can be -- and often are -- deadly.

It's not only the United States that is in a heat wave. Europe has been suffering this year, too; temperatures in Spain and Portugal have been approaching 115 degrees Fahrenheit this summer. We don't know the human cost of this heat wave yet, but a similar European heat wave in 2003 killed 70,000 people.

Article co-authored with Jackie Ratner.