Speaking to a crowd of more than 3,000 at Gustavus Adolphus College, Nobel Laureate Richard Alley laid out the science of climate change like the geosciences professor that he is.

Alley talked about the evidence from ice cores taken from deep in Greenland glaciers and sea-bed cores from deep below the ocean. He showed fossil records that highlighted the massive impact on life from previous hot periods in the Earth’s history.

And he showed the correlation between rising carbon dioxide levels and rising temperatures.

The evidence is beyond denial, according to Alley, a professor at Penn State and a recipient of the 2007 Nobel Peace Prize as a member of the Intergovernmental Panel on Climate Change.

“We have people who say, ‘Do you believe in global warming?’” Alley said. “Do you believe in gravity? It’s physics.”

Alley went beyond laying out the evidence during his lecture in the first day of Gustavus’ two-day Nobel Conference “Climate Changed: Facing Our Future.”

He insisted that immediate and meaningful action needs to be taken to reduce the severity of climate change repercussions — primarily by changing energy policy to transition from fossil fuels to renewable sources. The good news, Alley said, is that the transition is now feasible.

“It will take a huge effort to replace all that energy,” he said. “... But we now know we can do it.”

Alley, one of seven lecturers at the 55th annual Nobel Conference hosted by the St. Peter college, has worked for decades to reconstruct the history of the Earth’s changing climate going back hundreds of millions of years.

Much of his field work involved boring deep into Greenland’s ice fields and studying the layers in the cores of ice. Along with counting each layer that represents a winter of added snow and a summer of temporarily melted ice, the passing years could be detected by everything from radiation from atomic bomb tests in the 1950s to lead released into the atmosphere by mines operated by the Roman Empire 2,000 years ago.

“These are cores from almost a mile down,” Alley said of one slide he showed the audience at Lund Arena.

“What keeps screaming at us out of this history is that greenhouse gas is really important, CO2 is really important,” he said. “... Many things affect climate, but especially CO2. And there’s a whole lot of science behind that.”

Looking at fossil records provides lessons on how big changes in temperature resulted in devastating effects for the animals alive at the time. Fossil records in Wyoming when a major warming trend hit 59.9 million years ago show that populations of large mammals plunged.

“Pretty much everything that lived in Wyoming moved or died or both,” he said.

In the oceans, there were extreme migrations by sea creatures and localized extinctions.

Some who are skeptical that energy policy needs to be radically changed point to the evidence that huge swings in CO2 and equally huge changes in global temperature have happened repeatedly in Earth’s history.

Alley said he heard that from a U.S. senator and wonders if people sharing that believe would also agree that arson shouldn’t be a crime because there have always been fires or that homicide should be legal because death is inevitable.

“Can you imagine a senator saying people have always died so we shouldn’t worry about murder?”

The skyrocketing levels of carbon dioxide in the past two hundred years, caused by the burning of coal and other fossil fuels, is causing the Earth to rapidly warm and the trend will continue, Alley said. If nothing is done, the warming trend will be longer and more catastrophic.

While the Nobel Conference always draws large crowds to the Gustavus campus, there appears to be particularly intense interest in the global climate topic, according to spokesman JJ Aken. The 3,400 tickets available for each session of the Nobel Conference sold out two weeks ago, and more than 4,000 individual attendees are expected to attend at least one day of the conference.

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