June 20 (UPI) -- Scorching heat in Phoenix caused American Airlines to cancel 50 flights in and out of the city Tuesday.
American Airlines said that planes used for regional flights can operate in temperatures up to 118 degrees. But Phoenix temperatures are expected to reach 120 degrees.
City authorities issued an excessive heat warning and urged people to stay inside and stay hydrated.
"Heat of this magnitude is rare, dangerous and very possibly deadly," the National Weather Service in Phoenix said.
A major heat wave is occurring across the western United States and a new report says that will become more common in coming years.
A University of Hawaii study says 50 percent of the world's population will experience a month of deadly heat waves every year by the year 2100, no matter what the world's governments do to combat climate change.
"An increasing threat to human life from excess heat now seems almost inevitable, but will be greatly aggravated if greenhouse gases are not considerably reduced," the report stated.
"Our attitude towards the environment has been so reckless that we are running out of good choices for the future," said Camilo Mora, who led the team that did the study. "For heat waves, our options are now between bad or terrible. Many people around the world are already paying the ultimate price of heatwaves, and while models suggest that this is likely to continue to be bad, it could be much worse if emissions are not considerably reduced."
As excessive heat is to blame for canceled flights in and out of Phoenix, there could be more transportation issues in the northeast due to heavy rain and thunderstorms.