DAVID GREENE, HOST:
Global warming is something the planet will be wrestling with in the years to come. And there's some news this morning - the U.N.'s weather agency says the level of carbon dioxide in the atmosphere, which is linked to warming, reached a record level in 2013. In their annual report, the World Meteorological Organization says the increase from 2012 to 2013 was the biggest yearly increase in three decades.
STEVE INSKEEP, HOST:
This could be bad news for humans and also bad news for birds. A study out today from the National Audubon Society suggests that nearly half the bird species in the United States and Canada - nearly half - are at risk of extinction if no action is taken to protect them.
GREENE: David Yarnold is Audubon's president and CEO, and he said the seven-year study helped scientists understand the link between where birds live and the climate conditions they need to survive.
DAVID YARNOLD: The report looks at the underlying causes of climate, things like temperature and precipitation and humidity. And then we overlaid on top of that decades' worth of bird census data so that we can correlate what's happened with climate with what's happened with birds.
GREENE: So certain species of birds need temperatures, humidity, these things to sort of be at certain levels, and if they change, these species just can't exist?
YARNOLD: That's exactly right. So what happens when 40 species of Western songbirds keep having to fly higher and higher up Western mountains to find places to live? What happens when Minnesota's loons find that the weather is just too warm for them? They may not be able to fledge; they may not mate; they may not be able to find familiar food.
It's a little bit like going to a new place where you're not sure whether there would be water or power. Do you think that you'll be able to survive there? That's the question that this report poses. For 314 species, we know that there's a great probability that they're going to be facing very different climate futures, and their outcomes are really unsure.
GREENE: So let me just zero in if we can. And you mention loons in Minnesota - this is the species the common loon. And I think we have a little bit of tape to play, if people might, you know, even recognize this.
(SOUNDBITE OF COMMON LOON)
GREENE: So describe this species for me if you can.
YARNOLD: Yeah, so it's a lovely waterfowl. It's a bird that has been associated with Minnesota and with some other places in the Northeast for a very long time. And what the Audubon report says is that it's going to get too warm on a consistent basis for the loon to be able to spend its summers in Minnesota.
GREENE: I could imagine, you know, if we lose some bird species in the United States, others from farther south will come up and replace them?
YARNOLD: It's not likely that birds are going to migrate from Central and South America to replace them - maybe over very long periods of time that could happen. But remember, what we're talking about are changes at a pace and at a scale that we've never seen before. These are the kinds of changes to habitat that have taken tens of thousands of years in the past.
And what worries me is that these are the changes that my 9-month-old grandson could see in his lifetime. We're talking about things that are happening now and through the end of the century. This year in Southern California, 90 to 95 percent of raptor nests failed. There were no baby raptors because of drought. These things are happening now; this isn't some distant future.
GREENE: David, the headline that "The Survival Of Half Our Bird Species Could Be At Risk" is certainly attention-grabbing. In the debate over climate change, there are some who complain that sometimes there can be an alarmist quality to reports. What can you tell me about this report that would respond to that sort of question?
YARNOLD: There are models, there are forecasts that are far more extreme than this report. If anything, this report is conservative at every step of the way. We took great care to not overstate data or conclusions. Nothing would make us happier than to be wrong about the fate of many of these birds.
GREENE: David, we really appreciate you coming on the program. Thanks so much.
YARNOLD: You bet.
GREENE: That's David Yarnold. He's president and CEO of the National Audubon Society. And we should mention that common loon bird call you heard was given to us by the Cornell Lab of Ornithology.
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