John Yang:
What forecasters are calling an extremely dangerous heatwave is persisting in the West. And it’s expected to extend triple digit temperatures to the Midwest and East this weekend. Scientists say much of this heat as a long term result of greenhouse gas emissions, and it’s affecting everything from the power grid to trains, planes and automobiles.
Kristina Dahl is principal climate scientists with a Climate and Energy Program at the Union of Concerned Scientists. Kristina, let’s start by focusing on trains, planes and automobiles, how this heat is affecting transportation and the transportation infrastructure. Can you walk us through the sort of the big effects?
Kristina Dahl, Principal Climate Scientist, Union of Concerned Scientists: Absolutely. Heat affects all of these different types of infrastructure in different ways. For our cars and trucks that are running on asphalt roads, asphalt can deform or buckle when it’s extremely hot, so that can make road transportation difficult.
In terms of railroads, we know that rails can actually deform and buckle as well when it’s hot. Or if there are electric lines that the trains are connecting to overhead, those lines can sag. And that can cause problems for the trains and operators have to slow the trains down.
When it comes to airplanes, there are a few different effects and happen, the tarmac at our airports can deform when it’s hot, which causes problems as planes are trying to take off and land. But hot air also expands and becomes less dense. And that makes it harder for airplanes to get to the level of thrust they need to be able to take off. So when it’s really hot, all of these forms of transportation can be affected.