JUANA SUMMERS, HOST:
The record-breaking heat wave in Texas is dragging into a third week. China and India have also been hit by extreme heat recently. Scientists say climate change is a major driver. And something else is coming into play, too, the El Nino climate pattern. Lauren Sommer from NPR's Climate Desk has more.
LAUREN SOMMER, BYLINE: When it comes to understanding how climate change is making weather more extreme, heat waves are pretty much the clearest example out there.
KAI KORNHUBER: Heat waves are likely the one type of extreme weather event that is most directly associated with climate change.
SOMMER: Kai Kornhuber is a climate scientist with Columbia University and Climate Analytics, an extreme weather research group. He says the Texas heat wave, where records have been shattered for days in a row, shouldn't be surprising. When temperatures rise due to burning fossil fuels, it pushes heat waves into a new category.
KORNHUBER: They get hotter. They are occurring in higher frequency, so that also increases the likelihood of sequential heat waves.
SOMMER: And heat waves get longer, which means they take a bigger toll on our health. Extreme heat is the deadliest weather-related killer, especially in low-income and communities of color. And this year, there's something added, El Nino. It starts when the ocean in the central and eastern Pacific gets hotter. Daniel Swain, a climate scientist at the University of California, Los Angeles, says that makes the planet warmer.
DANIEL SWAIN: That's its role in the global climate system - is moving some of the energy up from depth and dumping it into the atmosphere.
SOMMER: This year, scientists are predicting El Nino could be quite strong. But it's just getting started, and there's a lag time.
SWAIN: That lag is because, of course, it takes some time for that extra heat near the surface of the ocean to actually make it into the atmosphere and be moved around by wind currents.
SOMMER: And because of El Nino, scientists say this year could be one of the hottest ever recorded. The last eight years were already the hottest since record keeping began.
SWAIN: Of course, the long-term driver is human-caused climate change, where we're sort of stair-stepping up along that inexorable upward trend.
SOMMER: El Nino is kind of like an exclamation point on that trend, he says, which means more heat waves are on the way in the near term. In the long term, avoiding more dangerous extremes will take cutting fossil fuels. Lauren Sommer, NPR News. Transcript provided by NPR, Copyright NPR.
