Concerns over athletes’ safety in high heat and humidity at the upcoming Olympics in Tokyo, Japan, likely presage quadrennial worries for the foreseeable future. Climate change is also forcing athletes to alter their training to prepare for less predictable conditions. “Probably every Olympics, we are going to have this conversation about, ‘What are you doing for heat and humidity?’” Randy Wilber, the U.S. Olympic and Paralympic Committee’s senior sports physiologist, told the Washington Post. (Washington Post $, CNN; Climate Signals background: Extreme heat and heatwaves)