News / Science & Technology

Ice Age Melt Offers Future Climate Clues

University of Wisconsin geologist Anders Carlson looking at an ice margin in south Greenland that is changing from being marine based to land based and thus slowing down and becoming more predictable. (Photo: Rob Hatfield, Oregon State University)
University of Wisconsin geologist Anders Carlson looking at an ice margin in south Greenland that is changing from being marine based to land based and thus slowing down and becoming more predictable. (Photo: Rob Hatfield, Oregon State University)
TEXT SIZE - +
Rosanne Skirble
When the climate began to warm during the last Ice Age about 23,000 years ago, much of the Northern Hemisphere was covered in ice. 

In two new studies published this week in Nature Geoscience, researchers describe how ice sheets behaved in the past could help scientists better predict what might happen to them in a warmer world of our future.  

University of Wisconsin geologist Anders Carlson studies ice sheet melt from land and ocean sediment cores.  His study describes what prehistoric Earth was like in North America and Northern Europe some 140,000 years ago.  

“What we found in this paper was that ice that’s resting on land it responded very quickly to the warming climate, but then it didn’t retreat really rapidly.  It kind of chugged along and slowly melted like an ice cube if you put a hair dryer on it,” Carlson says, adding that was not the case with ice sheets floating on the ocean. “Marine based ice sheets behave unpredictably.  They may not do anything for a while, and then they all of a sudden respond very abruptly. They can rapidly disappear.”
Ancient Glacier Melt
Ancient Glacier Melti
|| 0:00:00
...
 
🔇
X


Greenland and Antarctica hold the Earth’s last remaining ice sheets.  In July, satellite data showed that 97 percent of the surface of the Greenland ice sheet had turned to slush over four days, a rate faster than at any time in recorded history.  According to Carlson, it might be responding rapidly to small changes in temperature, similar to what he saw in the prehistoric record of ice sheets on land.
This marine-based glacier in the area of Greenland is retreating into land. (Photo: Kelsey Winsor/UW-Madison)This marine-based glacier in the area of Greenland is retreating into land. (Photo: Kelsey Winsor/UW-Madison)
x
This marine-based glacier in the area of Greenland is retreating into land. (Photo: Kelsey Winsor/UW-Madison)
This marine-based glacier in the area of Greenland is retreating into land. (Photo: Kelsey Winsor/UW-Madison)
 

“But that said, they haven’t catastrophically collapsed in the past either to rapidly raise sea level in the time scale that humans would care about, that we would be hard pressed to adapt to.”  Carlson says the Antarctic marine-based ice sheet is less predictable. “What this would say from the past is that these ice sheets, well they may not do anything for a bit.  But then if you want to catastrophically raise sea level like on the orders of a meter or two in human lifetime, there is prehistoric precedent for that happening.”  

 A second paper in Nature Geoscience looks back 12,000 to 7,000 years to when massive ice sheets still covered the high latitudes of the Northern Hemisphere.  At that time, the global climate was roughly comparable to what it is today and glaciers were melting.
Earth during the Ice Age 23,000 years ago with large ice sheets covering the Northern Hemisphere. (Credit: Anders Carlson)Earth during the Ice Age 23,000 years ago with large ice sheets covering the Northern Hemisphere. (Credit: Anders Carlson)
x
Earth during the Ice Age 23,000 years ago with large ice sheets covering the Northern Hemisphere. (Credit: Anders Carlson)
Earth during the Ice Age 23,000 years ago with large ice sheets covering the Northern Hemisphere. (Credit: Anders Carlson)

The study describes abrupt sea level jumps - from one-half to two meters - from melting glaciers. 

"What happens when you suddenly drain these massive amounts of fresh water into the ocean?  It’s going to change ocean circulation,” says co-author Torbjorn Tornqvist, an Earth scientist at Tulane University in Louisiana.   

Today, rapid melting from the Greenland ice sheet would send massive amounts of fresh water into the North Atlantic Ocean, changing the marine environment.   

“But it will also lead to potentially higher precipitation rates in the same region, which could also lead to fresher surface waters in the North Atlantic," Tornqvist says. "So we need to understand whether those types of changes could potentially be capable of triggering these kinds of abrupt climate events.”

Tornqvist adds that understanding how abrupt climate changes affect Earth’s geologic past can help design climate models that can better predict the future.

You May Like

Algerians Vote in Presidential Election

There were few media reports of protests and clashes around the country, but so far no significant violence More

Sharks More Evolved than Previously Thought

The discovery could “profoundly affect our understanding of evolutionary history” More

Pakistan Military Asked to Protect Polio Workers

Request comes as authorities say a Taliban ban on vaccinations in 2012 and deadly attacks on anti-polio teams have prevented thousands of children from getting inoculated More

This forum has been closed.
Comments
     
There are no comments in this forum. Be first and add one

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Google Buys Drone Companyi
|| 0:00:00
...
 
🔇
X
George Putic
April 15, 2014
In its latest purchase of high-tech companies, Google has acquired a manufacturer of solar-powered drones that can stay in the air almost indefinitely, relaying broadband Internet connection to remote areas. It is seen as yet another step in the U.S. based Web giant’s bid to bring Internet to the whole world. VOA’s George Putic reports.
Video

Video Google Buys Drone Company

In its latest purchase of high-tech companies, Google has acquired a manufacturer of solar-powered drones that can stay in the air almost indefinitely, relaying broadband Internet connection to remote areas. It is seen as yet another step in the U.S. based Web giant’s bid to bring Internet to the whole world. VOA’s George Putic reports.
Video

Video Ray Bonneville Sings the Blues and More on New CD

Singer/songwriter Ray Bonneville has released a new CD called “Easy Gone” with music that reflects his musical and personal journey from French-speaking Canada to his current home in Austin,Texas. The eclectic artist’s fan base extends from Texas to various parts of North America and Europe. VOA’s Greg Flakus reports from Austin.
Video

Video Millions Labor in Pakistan's Informal Economy

The World Bank says that in Pakistan, roughly 70 percent work in the so-called informal sector, a part of the economy that is unregulated and untaxed. VOA's Sharon Behn reports from Islamabad on how the informal sector impact's the Pakistani economy.
Video

Video Passover Celebrates Liberation from Bondage

Jewish people around the world are celebrating Passover, a commemoration of their liberation from slavery in Egypt more than 3,300 years ago. According to scripture, God helped the Jews, led by Moses, escape bondage in Egypt and cross the Red Sea into the desert. Zlatica Hoke reports that the story of the Jewish Exodus resonates with other people trying to escape slave-like conditions.
Video

Video Police Pursue Hate Crime Charges Against Kansas Shooting Suspect

Prosecutors are sifting through the evidence in the wake of Sunday’s shootings in a suburb of Kansas City, Missouri that left three people dead. A suspect in the shootings taken into custody is a white supremacist. As VOA’s Kane Farabaugh reports, he was well-known to law enforcement agencies and human rights groups alike.
Video

Video In Eastern Ukraine, Pro-unity Activists Emerge from Shadows

Amid the pro-Russian uprisings in eastern Ukraine, there is a large body of activists who support Ukrainian unity and reject Russian intervention. Their activities have remained largely underground, but they are preparing to take on their pro-Moscow opponents, as Henry Ridgwell reports from the eastern city of Donetsk.
Video

Video Basket Maker’s Skills Have World Reach

A prestigious craft show in the U.S. capital offers one-of-a-kind creations by more than 120 artists working in a variety of media. As VOA’s Julie Taboh reports from Washington, one artist lucky enough to be selected says sharing her skills with women overseas is just as significant.
Video

Video UN Report Urges Speedier Action to Avoid Climate Disaster

A new United Nations report says the world must switch from fossil fuels to cleaner energy sources to control the effects of climate change. The Intergovernmental Panel on Climate Change released the report (Sunday) following a meeting of scientists and government representatives in Berlin. The comprehensive review follows two recent IPCC reports that detail the certainty of climate change, its impacts and in this most recent report what to do about it. VOA’s Rosanne Skirble has the details.
AppleAndroid