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)
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

For Lebanon-based Refugees, Desperation Fuels Perilous Passage

In a war that has caused an estimated three million people to flee Syria, efforts to make perilous sea journey in search of asylum expected to increase More

South African Brewer Tackles Climate Change

Mega-brewer SAB Miller sent delegates to climate summit in Peru, says it is one of many private companies taking their own steps to fight climate change More

Indonesia Reports Increase in Citizens Joining Islamic State

Officials say more than 350 of its citizens are now in Syria or Iraq to fight with Islamic State - 50 more than last month 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.
Will Pakistan School Shooting Galvanize Pakistan Against Extremism?i
X
Ayesha Tanzeem
December 17, 2014 11:54 AM
The attack on a military school in Pakistan’s northwest city of Peshawar left 141 dead, including 132 children. Strong statements of condemnation poured in from across the world. The country announced three days of mourning, and the leadership, both political and military, promised retribution. VOA's Ayesha Tanzeem looks at how likely the Pakistani government is to clamp down on all extremist groups.
Video

Video Will Pakistan School Shooting Galvanize Pakistan Against Extremism?

The attack on a military school in Pakistan’s northwest city of Peshawar left 141 dead, including 132 children. Strong statements of condemnation poured in from across the world. The country announced three days of mourning, and the leadership, both political and military, promised retribution. VOA's Ayesha Tanzeem looks at how likely the Pakistani government is to clamp down on all extremist groups.
Video

Video ‘Anti-Islamization’ Marches Increase Tensions In Germany

Anti-immigrant rallies in Germany have been building in recent weeks, peaking Monday night in the city of Dresden where tens of thousands of people turned out to demonstrate against what they call the ‘Islamization’ of the West. Germany has offered asylum to more Syrian refugees than any other country, and this appears to have set off the protests. Henry Ridgwell reports from London.
Video

Video Aceh Rebuilt Decade After Tsunami, But Scars Remain

On December 26, 2004 there was an earthquake in the Indian Ocean so powerful it caused the Earth’s axis to wobble a few centimeters. Onshore on the island of Sumatra, the resulting tsunami was devastating. A decade later, VOA Correspondent Steve Herman reports from Banda Aceh, Indonesia, where although there is little remaining evidence of the physical devastation, the psychological scars among survivors remain.
Video

Video Refugees Living in Kenya Long for Peace in the Home Countries

Kenya is host to numerous refugees seeking safe haven from conflict. Immigrants from Somalia face challenges in their new lives in Kenya. Ahead of International Migrants Day (December 18) Lenny Ruvaga has more for VOA News from the Kenyan capital.
Video

Video Turkey's Authoritarianism Dismays Western Allies

The Turkish government has been defiant in the face of criticism at home and abroad for its raids targeting opposition media. The European Union on Monday expressed dismay after President Recep Tayyip Erdogan lashed out at Brussels for criticizing his government's action. Turkey's bid to be considered for EU membership has been on hold while critics accuse the NATO ally of increasingly authoritarian rule. Zlatica Hoke reports.
Video

Video US-China Year in Review: Hong Kong to Climate Change

The United States is pushing for a code of conduct to resolve territorial disputes in the South China Sea as it works to improve commercial ties with Beijing. VOA State Department correspondent Scott Stearns reports on a year of U.S. policy toward China from Hong Kong to climate change.
Video

Video Japanese Leader’s Election Win Raises Potential for Conflict with Neighbors

Japan’s Prime Minister Shinzo Abe and his allies easily won a two-thirds majority in parliament Sunday, even though the country has slipped into recession under his conservative policies. VOA’s Brian Padden reports from Seoul, that the prime minister’s victory will empower him to continue economic reforms but also pursue a nationalist agenda that will likely increase tensions with Japan’s neighbors.
Video

Video Nuba Mountain Families Hide in Caves to Escape Aerial Bombings

Despite ongoing peace talks between Sudan's government and the rebel Sudan People’s Liberation Movement-North, or SPLM-N, daily aerial attacks continue in South Kordofan province’s Nuba Mountains. Adam Bailes was there and reports for VOA that government forces are targeting civilian areas, rather than military positions, with their daily bombardments.

All About America

AppleAndroid