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Ice Ages and Climate Changes - Lecture recap

Report on “Ice Ages and Climate Changes” event, June 20, 2015 (by Russ Dobler)

Just when you thought we were finally through with winter in New York, paleoclimatologist Athanasios Koutavas just had to open his lecture with a slide depicting our fair city under almost two miles of ice. One June 20, the day before summer, no less!


But hey, that was 21,000 years ago. A lot of that ice has since melted into the ocean – more than past trends might have predicted – and instead of bundling up, Koutavas began by wondering “how far up the mountain I should buy my property.”

Well, maybe everyone would be safe if we all moved to Greenland. As the Lamont-Doherty and CUNY Staten Island researcher told the New York City Skeptics audience at his “Ice Ages and Climate Changes” presentation, that’s the one place still covered by a bit of the Laurentide ice sheet. If it’s all but gone, how do we even know it was here?

“Glaciers act almost like conveyer belts,” Koutavas said. In doing so, the material stuck on the bottom carves great grooves, called striations, into the rock beneath them. Central Park’s Umpire Rock is a famous example of this phenomenon.


Umpire Rock, from

Large, out-of-place-looking boulders called erratics are also clear tip-offs of glaciation, Koutavas told the crowd. These strangers are carried on top of the ice sheet as it flows south, and are deposited in unfamiliar territory when it recedes.

“Basically, these are the calling cards of the glacier,” Koutavas said.



Moving east, Long Island is known not for material that came from underneath or on top of a glacier, but for the accumulation of stuff that was pushed along the leading edge as it advanced. The Ronkonkoma and Harbor Hill moraines stand 400 feet above sea level as reminders of how powerful a lump of ice can really be.

“Of course they also created some very expensive real estate,” Koutavas said.

Koutavas explained that glaciation of the Earth’s northern hemisphere is cyclical, and while New York is currently uncovered, the massive ice blocks will eventually, undoubtedly, return. The only question is when.


“How long would we have to wait for natural forces to bring us back into the next Ice Age?” Koutavas asked.  If we can’t answer that, he said, we don’t understand natural dynamics as well as we think we do. Of course, it doesn’t help that the results of human activity are now superimposed onto these natural cycles.

Koutavas believes that we began to enter the next great period of glaciation around the year 1300, at the beginning of what’s sometimes called the “Little Ice Age.” During that time period, England’s Thames River would freeze often enough to have Frost Fairs in the 1600s, and there are even reports of New Yorkers being able to walk across the ice from Manhattan to Staten Island in the 1870s.


Etching of the frozen East River, 1867

At that point, though, the world strangely began to warm again, pushing back against the apparent natural forces. Koutavas observed this is about when the Industrial Revolution began, but stopped short of singling out the technological shift as the main culprit.

To close, Koutavas noted something else unexpected, the so-called “global warming hiatus,” a period of worldwide temperature “flattening” which contradicts the continual increase predicted by most climate models. The anomaly began around 1998, but in 2015, at least one study has suggested the trend may be an artifact that doesn’t really represent reality.

Either way, the simple fact that these discussions take place out in the open should be enough to show climate change conspiracy theorists that the field’s experts are not united in lockstep, pressing an agenda. But then again, thanks to the coming El Niño, most do agree that 2015 will be the hottest year in recorded history.