Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Clouds, like blankets, trap heat and are melting the Greenland Ice Sheet

13.01.2016

The Greenland Ice Sheet is the second largest ice sheet in the world and it's melting rapidly, likely driving almost a third of global sea level rise.

A new study shows clouds are playing a larger role in that process than scientists previously believed.


A new study shows clouds are playing a larger role in heating the Greenland Ice Sheet than scientists previously believed, raising its temperature by 2 to 3 degrees compared to cloudless skies and accounting for as much as 30 percent of the ice sheet melt.

Credit: Hannes Grobe

"Over the next 80 years, we could be dealing with another foot of sea level rise around the world," says Tristan L'Ecuyer, professor in the Department of Atmospheric and Oceanic Sciences at the University of Wisconsin-Madison and co-author of the study. "Parts of Miami and New York City are less than two feet above sea level; another foot of sea level rise and suddenly you have water in the city."

The study, published today (Jan. 12, 2016) in Nature Communications and led by the University of Leuven in Belgium, shows that clouds are raising the temperature of the Greenland Ice Sheet by 2 to 3 degrees compared to cloudless skies and accounting for as much as 30 percent of the ice sheet melt.

Numerous statements in the Nobel Peace Prize-winning 2007 Intergovernmental Panel on Climate Change report address the need to better account for clouds in climate models, L'Ecuyer says. Arctic clouds are no exception, especially since climate models have not kept pace with the rate of melting actually observed on the Greenland Ice Sheet.

"With climate change at the back of our minds, and the disastrous consequences of a global sea level rise, we need to understand these processes to make more reliable projections for the future," says Kristof Van Tricht, the University of Leuven graduate student who led the study. "Clouds are more important for that purpose than we used to think."

But in order to better understand them, the right technology needed to be in place.

"Within the last 10 years, NASA launched two satellites that have just completely changed our view of what clouds look like around the planet," says L'Ecuyer, who is affiliated with the UW-Madison Space Science and Engineering Center, where satellite meteorology was born. "Once you know what the clouds look like, you know how much sunlight they're going to reflect and how much heat from Earth's surface they're going to keep in."

When it comes to heat, clouds essentially behave in two ways: They either cool the Earth's surface by reflecting sunlight back into space, or, like a thick blanket, they trap heat at the surface -- the greenhouse effect of clouds. On Greenland, which is covered in bright, light-reflecting snow, clouds primarily act to trap heat.

Using the two satellites -- CloudSat and CALIPSO -- L'Ecuyer was able to take "X-ray images" of Greenland's clouds from space between 2007 and 2010 and determine their structure, how high they were in the atmosphere, their vertical thickness, and their composition (ice or liquid).

The Belgian team combined this data with ground-based observations, snow model simulations and climate model data to map the net effect of clouds. They learned that cloud cover prevents the ice that melts in the sunlight of day from refreezing at night.

"A snowpack is like a frozen sponge that melts during the day," says Van Tricht, who spent six weeks in Madison last year working with L'Ecuyer. "At night, clear skies make a large amount of meltwater in the sponge refreeze. When the sky is overcast, by contrast, the temperature remains too high and only some of the water refreezes. As a result, the sponge is saturated more quickly and excess meltwater drains away."

Researchers already know that while clouds can change the climate, the climate can also change clouds, a phenomenon known as cloud-climate feedback. L'Ecuyer is optimistic that the study -- a good example of how satellites are helping us solve the complicated cloud-climate feedback problem -- will improve future climate models, to help scientists and policymakers across the world adapt to climate change.

With a background in physics, L'Ecuyer is driven to study clouds by a desire to better understand how people and society are affected by the natural world. "Many of the countries most susceptible to sea level rise tend to be the poorest; they don't have the money to deal with it," he says. "This is something we have to get right if we want to predict the future."

###

CONTACT: Tristan L'Ecuyer, 608-890-2107, tlecuyer@wisc.edu

Kelly April Tyrrell, kelly.tyrrell@wisc.edu, 608-262-9772

Media Contact

Tristan L'Ecuyer
tlecuyer@wisc.edu
608-890-2107

 @UWMadScience

http://www.wisc.edu 

Tristan L'Ecuyer | EurekAlert!

More articles from Earth Sciences:

nachricht Researchers find higher than expected carbon emissions from inland waterways
25.05.2016 | Washington State University

nachricht Rutgers scientists help create world's largest coral gene database
24.05.2016 | Rutgers University

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Computational high-throughput screening finds hard magnets containing less rare earth elements

Permanent magnets are very important for technologies of the future like electromobility and renewable energy, and rare earth elements (REE) are necessary for their manufacture. The Fraunhofer Institute for Mechanics of Materials IWM in Freiburg, Germany, has now succeeded in identifying promising approaches and materials for new permanent magnets through use of an in-house simulation process based on high-throughput screening (HTS). The team was able to improve magnetic properties this way and at the same time replaced REE with elements that are less expensive and readily available. The results were published in the online technical journal “Scientific Reports”.

The starting point for IWM researchers Wolfgang Körner, Georg Krugel, and Christian Elsässer was a neodymium-iron-nitrogen compound based on a type of...

Im Focus: Atomic precision: technologies for the next-but-one generation of microchips

In the Beyond EUV project, the Fraunhofer Institutes for Laser Technology ILT in Aachen and for Applied Optics and Precision Engineering IOF in Jena are developing key technologies for the manufacture of a new generation of microchips using EUV radiation at a wavelength of 6.7 nm. The resulting structures are barely thicker than single atoms, and they make it possible to produce extremely integrated circuits for such items as wearables or mind-controlled prosthetic limbs.

In 1965 Gordon Moore formulated the law that came to be named after him, which states that the complexity of integrated circuits doubles every one to two...

Im Focus: Researchers demonstrate size quantization of Dirac fermions in graphene

Characterization of high-quality material reveals important details relevant to next generation nanoelectronic devices

Quantum mechanics is the field of physics governing the behavior of things on atomic scales, where things work very differently from our everyday world.

Im Focus: Graphene: A quantum of current

When current comes in discrete packages: Viennese scientists unravel the quantum properties of the carbon material graphene

In 2010 the Nobel Prize in physics was awarded for the discovery of the exceptional material graphene, which consists of a single layer of carbon atoms...

Im Focus: Transparent - Flexible - Printable: Key technologies for tomorrow’s displays

The trend-forward world of display technology relies on innovative materials and novel approaches to steadily advance the visual experience, for example through higher pixel densities, better contrast, larger formats or user-friendler design. Fraunhofer ISC’s newly developed materials for optics and electronics now broaden the application potential of next generation displays. Learn about lower cost-effective wet-chemical printing procedures and the new materials at the Fraunhofer ISC booth # 1021 in North Hall D during the SID International Symposium on Information Display held from 22 to 27 May 2016 at San Francisco’s Moscone Center.

Economical processing

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Networking 4.0: International Laser Technology Congress AKL’16 Shows New Ways of Cooperations

24.05.2016 | Event News

Challenges of rural labor markets

20.05.2016 | Event News

International expert meeting “Health Business Connect” in France

19.05.2016 | Event News

 
Latest News

LZH shows the potential of the laser for industrial manufacturing at the LASYS 2016

25.05.2016 | Trade Fair News

Great apes communicate cooperatively

25.05.2016 | Life Sciences

Thermo-Optical Measuring method (TOM) could save several million tons of CO2 in coal-fired plants

25.05.2016 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>