Climate change means these kind of extreme heat waves will become more common. One study for the U.S. predicted a four-fold increase in the number of days with extreme heat by 2050.

For most big cities globally, it is now not a question of if they will get hit by a heat wave, but when.

The good news is that the world’s cities are increasingly aware of this threat.

Groups like C40 and ICLEI have formed collective teams, with staff from multiple cities sharing ideas and techniques about how to reduce the effects of urban heat waves.

And conservation scientists are increasingly ready to do their part in helping cities adapt to climate change.

We can quantify the benefit of tree planting to air temperatures and human health, and we are increasingly helping cities plan where to plant trees to get maximum benefit.