NOEL KING, HOST:
All right. Now a story about the science and the politics of climate change. The planet has been warming for decades. 2018 is on track to be one of the hottest years on record. This year we also saw a bunch of new and more precise predictions from scientists about what climate change is doing to the weather. The Trump administration questions that science. NPR's Christopher Joyce has the story.
CHRISTOPHER JOYCE, BYLINE: So are we stuck with climate change? You could ask the president, as reporters from Axios on HBO did.
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PRESIDENT DONALD TRUMP: Is there climate change? Yeah. Will it go back like this? I mean, will it change back? Probably. That's what I think.
JOYCE: You could ask a senator about climate change, as a reporter did to Republican Ted Cruz from Texas when he was campaigning this fall.
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TED CRUZ: Well, listen. Of course, the climate is changing. The climate has been changing from the dawn of time. The climate will change as long as we have a planet Earth.
JOYCE: Or you could ask actual climate scientists what they think, like Martin Hoerling, who was attending the annual meeting of the American Geophysical Union in December.
MARTIN HOERLING: We're not seeing cycles. We're not seeing things that are going to revert back.
JOYCE: What about that idea that the climate is always changing? Here's climate scientist Stephanie Herring.
STEPHANIE HERRING: The current change that we're experiencing now is particularly alarming. And that is because in the history of human civilization, the climate has never changed this rapidly.
JOYCE: Hoerling and Herring work for the National Oceanic and Atmospheric Administration. It was a big year for NOAA and other federal agencies that do science. The government issued a national climate assessment. It said climate change is real. Humans are causing it. And it's worse than ever. Earlier this year, the highly regarded Intergovernmental Panel on Climate Change came to a similar conclusion. If the Earth warms up another half a degree Fahrenheit, which is very likely, the world's weather will change drastically. In fact, it's already changing. There was yet another study about extreme weather in 2017 - lots of huge rainstorms around the world, for example, and some very wet hurricanes. Martin Hoerling says it's all about warmer oceans.
HOERLING: To have more water vapor in the air simply delivering heavier rain when it rains. The physics of what's driving heavier rains even when it's not a hurricane are virtually the same in many locations.
JOYCE: The physics isn't complicated. Just heat water in a pot on your stove and watch as it evaporates and rises. It will come back down again. Just ask people who lived through hurricanes in Houston, Florida or Puerto Rico. The last two years have seen abnormally strong hurricane seasons in the Atlantic. The extreme weather report comes annually from the American Meteorological Society - scientists again, not politicians. It's all about so-called attribution science - determining when a big storm or fire or heat wave is normal or pumped up by a warmer climate. Hoerling says the science has improved. And it's revealing just what a warmer world means.
HOERLING: With seven years of these reports, we're seeing more and more evidence building that heat waves are not only happening more often. Their magnitudes is off the charts.
JOYCE: Scientists have also attributed bigger fires to climate change. Physics again - hotter, drier air turns vegetation into tinder. The stronger link between climate and weather makes it harder to question that the climate is changing. And it has people worried that they may be held liable if they don't plan for that - attorney Lindene Patton's clients, for example, people who build things.
LINDENE PATTON: You need to go in as a practicing architect or engineer and plan for a different environment, especially for long-lived assets.
JOYCE: Things like...
PATTON: Roads, buildings, homes. That's where this type of information that attribution science is generating is informing decision taking.
JOYCE: So that you won't get sued for failing to build for a warmer world. Patton, who's with the firm Earth & Water Law Group, is also getting calls about climate liability from another group of worried people, politicians. Christopher Joyce, NPR News.
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