University of Minnesota geologist on climate change study: "It's a warning"

Arctic sea ice is at the second-lowest point ever measured.

Arctic sea ice is at the second-lowest point ever measured.

About 11,500 years ago, at the tail end of the Pleistocene era, the Earth began to warm up. The planet's climate has fluctuated since time immemorial. But this period of climate change came less like a stone warming in the sun, and more like a marshmallow in a microwave.

In Greenland, the average annual temperature shot up 61 degrees Fahrenheit -- in less than 10 years. 

Larry Edwards, director of the Department of Earth Sciences at the University of Minnesota, has studied this and other rapid shifts in Earth's climate, and recently contributed his expertise to a climate change study that literally spanned the globe and the last 800,000 years.

That research shows that such "abrupt shifts" in climate happen fairly often, and that they effect every inch of the planet. The findings are timely: Just yesterday, researchers announced that Arctic Sea ice had been measured at the second-lowest point in history, and still more of it might be melting.

Edwards' research predates the modern period of man-made climate change, but he said dramatic changes like the ones he's seen in the historical record must be kept in mind today.

"If we push hard enough," Edwards said, "we could generate an abrupt shift. So it's not a prediction -- in a sense, it's more of a warning."

The 1.67 million square miles of ice, measured on September 9 by satellite images, is the second-lowest reading since the first data was collected in 1979, according to the National Snow and Ice Data Center. The only lower number came in 2007, a year in which the NSIDC says that weather conditions -- like unusually clear skies and wind patterns -- would've led to more ice melting, while this year's weather has "shown more typical weather patterns but continued warmth over the Arctic."

"This," the NSIDC wrote, "supports the idea that the Arctic sea ice cover is continuing to thin."

Edwards' latest research project, on which he collaborated with scientists from Maine, England, Wales, Germany and France, studied both the Arctic and Antarctic, and stretched back hundreds of thousands of years before humans even existed.

The study, published last week by the journal "Science," tracked abrupt changes in temperature over the last 800,000 years, using Antarctic ice and data from caves in Greenland.  Edwards, a scientific pioneer in reading climate change using cave materials, analyzing stalactites and stalagmites, which offer a highly accurate look at historical temperatures.

The Antarctic ice are the oldest climate records of any kind, but Greenland's cave formations go back 120,000 years, and Edwards has studied caves in China where formations go back 400,000 years. Edwards work includes collecting cave data on five continents over the last 20-plus years, and he says the numbers sync up: On repeated instances, the Earth's experienced violent swings in temperature that have changed the global climate.

The Greenland warming period 11,500 years ago -- in the long view of history, an eye-blink ago -- was a good one for plants and animals, bringing that country from a totally-frozen state to a more moderate climate that would support living things. But if even a much lesser period of warming took place there now, Edwards says the results would be "catastrophic."

"If you have tremendous warming, Greenland and Antarctica's ice would begin to melt," Edwards said, "and the ocean levels would rise tremendously. Every coastal city in the world would be underwater."

One of Edward's colleagues refers to this as the "train-wreck scenario," meaning that, like your train running off the rails, it's unlikely, but would spell certain disaster.

Research proving that natural climate change has occurred in history seems to support the view of opponents of man-made climate change, who say the current period of warming is just a natural swing. Edwards says that's wrong, and that, against the best records of the last 1,000 years, modern warming is "an anomaly."

"You can say, 'yeah, there's been changes to climate in the past,'" Edwards said. "But when you compare the climate to what it's been in the past 1,000 years -- when the things that effect climate have not changed that much -- what's happening today is different."

Edwards is not an alarmist, and says man-made climate change causing an abrupt shift, one that would almost certainly end human life on Earth, has a "small chance of happening." No one living today will face the "train-wreck," says Edwards, who thinks man-made causes won't add up until the next couple hundred years.

"But if we keep on going 'business as usual' another century, two centuries," he said, "then all bets are off. The further you go into this, you kind of go into the unknown."