What forecasters are calling an extremely dangerous heat wave 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 is a long-term result of greenhouse

gas emissions and it's affecting everything from the power grid to trains, planes and

automobiles. Christina Dahl is principal climate scientists

for the Climate and Energy Program

at the Union of Concerned Scientists.

Christina, let's start by focusing on trains,

and automobiles, how this heat is affecting transportation and the transportation

infrastructure.

Can you walk us through the sort of the big effects?

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. 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

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