Featured Research

from universities, journals, and other organizations

'Hidden plumbing' helps slow Greenland ice flow: Hotter summers may actually slow down flow of glaciers

Date:
January 27, 2011
Source:
University of Leeds
Summary:
Hotter summers may not be as catastrophic for the Greenland ice sheet as previously feared and may actually slow down the flow of glaciers, according to new research.

An aerial view showing water converging on a moulin in the West Greenland Ice Sheet. A moulin is a narrow, tubular shaft in a glacier that provides a pathway for water to travel from the glacier's surface to its bottom.
Credit: NASA/JPL

Hotter summers may not be as catastrophic for the Greenland ice sheet as previously feared and may actually slow down the flow of glaciers, according to new research.

A letter published in Nature on 27 January explains how increased melting in warmer years causes the internal drainage system of the ice sheet to 'adapt' and accommodate more melt-water, without speeding up the flow of ice toward the oceans. The findings have important implications for future assessments of global sea level rise.

The Greenland ice sheet covers roughly 80% of the surface of the island and contains enough water to raise sea levels by 7 metres if it were to melt completely. Rising temperatures in the Arctic in recent years have caused the ice sheet to shrink, prompting fears that it may be close to a 'tipping point' of no return.

Some of the ice loss has been attributed to the speed-up of glaciers due to increased surface melting. Each summer, warmer temperatures cause ice at the surface of the sheet to melt. This water then runs down a series of channels to the base of the glacier where it acts as a lubricant, allowing the ice sheet to flow rapidly across the bedrock toward the sea.

Summertime acceleration of ice flow has proved difficult for scientists to model, leading to uncertainties in projections of future sea level rise.

"It had been thought that more surface melting would cause the ice sheet to speed up and retreat faster, but our study suggests that the opposite could in fact be true," said Professor Andrew Shepherd from the University of Leeds School of Earth and Environment, who led the study.

"If that's the case, increases in surface melting expected over the 21st century may have no affect on the rate of ice loss through flow. However, this doesn't mean that the ice sheet is safe from climate change, because the impact of ocean-driven melting remains uncertain."

The researchers used satellite observations of six landlocked glaciers in south-west Greenland, acquired by the European Space Agency, to study how ice flow develops in years of markedly different melting.

Although the initial speed-up of ice was similar in all years, slowdown occurred sooner in the warmest ones. The authors suggest that in these years the abundance of melt-water triggers an early switch in the plumbing at the base of the ice, causing a pressure drop that leads to reduced ice speeds.

This behaviour is similar to that of mountain glaciers, where the summertime speed-up of ice reduces once melt-water can drain efficiently.

Study co-author Dr Edward Hanna from the University of Sheffield added: "This work also underlines the usefulness of modern gridded climate datasets and melt-model simulations for exploring seasonal and year-to-year variations in Greenland ice sheet dynamics and their relationship with the global climate system."

The study was funded by the Natural Environment Research Council's National Centre for Earth Observation, the Philip Leverhulme Trust, and by the European Commission Ice2Sea project.


Story Source:

The above story is based on materials provided by University of Leeds. Note: Materials may be edited for content and length.


Journal Reference:

  1. Aud Venke Sundal, Andrew Shepherd, Peter Nienow, Edward Hanna, Steven Palmer, Philippe Huybrechts. Melt-induced speed-up of Greenland ice sheet offset by efficient subglacial drainage. Nature, 2011; 469 (7331): 521 DOI: 10.1038/nature09740

Cite This Page:

University of Leeds. "'Hidden plumbing' helps slow Greenland ice flow: Hotter summers may actually slow down flow of glaciers." ScienceDaily. ScienceDaily, 27 January 2011. <www.sciencedaily.com/releases/2011/01/110126131538.htm>.
University of Leeds. (2011, January 27). 'Hidden plumbing' helps slow Greenland ice flow: Hotter summers may actually slow down flow of glaciers. ScienceDaily. Retrieved October 1, 2014 from www.sciencedaily.com/releases/2011/01/110126131538.htm
University of Leeds. "'Hidden plumbing' helps slow Greenland ice flow: Hotter summers may actually slow down flow of glaciers." ScienceDaily. www.sciencedaily.com/releases/2011/01/110126131538.htm (accessed October 1, 2014).

Share This



More Earth & Climate News

Wednesday, October 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Earth Has Lost Half Its Vertebrate Wildlife Since 1970: WWF

Earth Has Lost Half Its Vertebrate Wildlife Since 1970: WWF

Newsy (Sep. 30, 2014) A new study published by the World Wide Fund for Nature found that more than half of the world's wildlife population has declined since 1970. Video provided by Newsy
Powered by NewsLook.com
Seismic Activity Halts Recovery at Japan Volcano

Seismic Activity Halts Recovery at Japan Volcano

AP (Sep. 30, 2014) Rescuers were forced to suspend plans to recover at least two dozen bodies from near the summit of Mount Ontake in central Japan on Tuesday after increased seismic activity raised concern about the possibility of another eruption. (Sept. 30) Video provided by AP
Powered by NewsLook.com
Dolphins Might Use Earth's Magnetic Field As A GPS

Dolphins Might Use Earth's Magnetic Field As A GPS

Newsy (Sep. 30, 2014) A study released Monday suggests dolphins might be able to sense the Earth's magnetic field and possibly use it as a means of navigation. Video provided by Newsy
Powered by NewsLook.com
How To Battle Stink Bug Season

How To Battle Stink Bug Season

Newsy (Sep. 30, 2014) Homeowners in 33 states grapple with stink bugs moving indoors at this time of year. Here are a few tips to avoid stink bug infestations. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins