GUY RAZ, host:
This is ALL THINGS CONSIDERED from NPR News. I'm Guy Raz.
Sometimes, climate science and history have a way of overlapping, and in a few moments, we'll hear how an atmospheric physicist stumbled upon data that may have solved the mystery of George Mallory's deadly expedition to Mount Everest in 1924. But first, another climate story.
A few days ago, Andreas Muenchow, a professor at the University of Delaware, got a call from some colleagues in Canada. Muenchow had been looking at a specific glacier in Greenland for years. It's called the Petermann Glacier, and on Thursday he found out that a massive chunk of it broke off to form an ice island.
Mr. ANDREAS MUENCHOW (Professor, University of Delaware): This ice island is about the size four times Manhattan.
RAZ: That's 92 square miles, the largest iceberg to form in the Arctic since 1962. And over the next three years, that ice island will melt away into the ocean, 18 cubic kilometers of water.
Mr. MUENCHOW: Which is the equivalent of kind of like about 120 days' worth of what people in the U.S. use out of their tap water for showering and drinking and sprinkling their lawns.
RAZ: Now, these things happen. Icebergs naturally break off into the Arctic. It's just that they're happening with greater frequency today, and Andreas Muenchow doesn't know just yet if this ice break has anything to do with climate change.
But you only have to look at satellite pictures of Greenland to see that more of it is melting away faster than at any other time in recorded history.
Now, it just so happens that 35 years ago on this day, August 8, a then-obscure geochemist at Columbia University named Wallace Broecker published a journal article that, for the first time, used the term global warming. And as you might expect, it caused a sensation.
Mr. WALLACE BROECKER (Newberry Professor, Department of Earth and Environmental Sciences, Columbia University): I don't think people paid all that much attention to it, actually.
RAZ: Okay, not quite a sensation. The article in question, in the journal Science, passed with barely a mention. It was called "Are We On the Brink of a Pronounced Global Warming?" Broecker was arguing that the Earth was about to get a whole lot hotter, and he was trying to crack a scientific puzzle.
Humans were pouring more and more carbon into the atmosphere, from their cars and factories, and it meant that the Earth should have been getting warmer. But at that point, it wasn't.
Mr. BROECKER: And it puzzled me, and so I was looking for a reason, and I came upon a record, a new record from Greenland ice core, which suggested that there were fluctuations, and the latest one was a cooling.
So I proposed that perhaps the cooling had been balancing out the CO2 warming, you know, natural cooling.
RAZ: In other words, the cooling was masking the fact that there should have been a warming based on, I guess, science, on physics, that more CO2 in the atmosphere should have been heating the Earth up.
Mr. BROECKER: Exactly, and the cycles that were seen in the ice core from Greenland, one of them had an 80-year period. So the 40 years of plateau, no warming, corresponded to half of the, I should say, 80-year cycle.
And so I proposed in the article that if that were the case, then the situation should turn around in short order, and we should see a natural warming, which would join forces with the CO2 warming.
RAZ: In other words, when that natural cooling cycle ended, then there would be a natural heating cycle, but that would join forces with the artificial elements that the carbon that humans were putting into the atmosphere, and that would creating a kind of a super-warming?
Mr. BROECKER: Yes, that's what I proposed. And that article was published, of course, in 1975, and lo and behold, in 1976, the temperature started to rise, and it's been rising more or less ever since.
RAZ: Now, your predictions turned out obviously to be correct, accurate. This July was the warmest on record in the U.S. I mean, are you surprised that it was so accurate?
Mr. BROECKER: Well, it was dumb luck, because it turns out that the record in Greenland was a very unusual record, and as we over the years got more and more records, the cycles that showed up so strongly in this Northern Greenland ice core didn't show up anywhere else.
So one might say that my prediction was based on, you know, in a sense, nonsense.
(Soundbite of laughter)
Mr. BROECKER: But on the other hand, it turned out to be correct. So maybe there's something going on in my head that I don't understand.
RAZ: That's Wallace Broecker. He's a professor of geochemistry at Columbia University and the man who coined the phrase global warming 35 years ago today. Wallace Broecker, thank you so much.
Mr. BROECKER: Well, I'm pleased to be here.
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