Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Melting ice important indicator of global warming


Surrounded by winter snow and ice, melting seems like a good thing, but, on a global scale, the melting of ice sheets and glaciers is a sign of global warming, according to a Penn State glaciologist.

"The really big picture shows change in the ice and those changes look like what we get is a world that is a little warmer," says Dr. Richard B. Alley, the Evan Pugh Professor of Geosciences. "We currently do not include all these processes in the models that predict the global future."

Summarizing published literature, Alley notes that spring snows in the Arctic have decreased without a decrease in overall precipitation. A shift in the snowy season is an indication of warming. As seen by satellites, Arctic sea ice is smaller and sea ice thickness measured by submarines is thinner.

"For the time period with especially good records, northern sea ice clearly shows a downward trend," says the Penn State researcher. "There may also be a downward trend in the south."

One explanation for the changes in the Arctic sea ice is a change in the circulation of the oceans and atmosphere. But the circulation change, which itself may be brought on by warming, does not seem to fully explain the changes in sea ice. Atmospheric warming may simply be causing melting.

"Mountain glaciers are typically more sensitive to temperature than other controls," says Alley. "Most mountain glaciers are getting smaller. Some are disappearing, others just shrinking."

Recent reports indicate that the large ice sheets in Antarctica and on Greenland are growing fatter in the middle due to slightly increased snow. Increased snow may be a sign of warming because warmer air holds more moisture for precipitation. In a few places on the margins of the ice, the ice sheets are getting smaller. The water from the shrinking ice sheets slightly raises ocean levels. "Both of these changes look like some sort of response to environmental warming," says Alley.

For floating ice, warm water beneath the ice sheet and warm air both may contribute to melting. But the real problem is that changes in the ice sheets are complicated, it is not simply melting. The centers of the ice sheets change on a scale of tens of thousands of years, while the edges change in years.

"We have been modeling ice sheets using ice flow models based on local information at the center of the ice sheets," says Alley. "But the ice sheets act globally as well."

The Penn State researcher explains that the models assume that if you push on one side of the ice sheet, the far side does not move. No transfer of energy takes place through the sheet. However, this approach does not work on a floating section of the ice sheet, the ice shelves. If you push on one side, the entire sheet moves.

"We have found that if the ice shelf calved off or a section melted, that the actual ice flow movement was much faster than our current models suggest," says Alley.

Obviously, some physical processes are not in the current models and these are important to the overall picture of the ice. Even little ice shelves can be important.

"However, if we include everything, everywhere, it will take a great deal of computer power and we are not quite ready for that yet," says the Penn State researcher.

What is clear is that ice around the globe is changing and the models are not adequate to fully understand what this means for the future.

"The ice changes are best explained by warming. Now we have to decide how to make better models and how to deal with the effects of warming," says Alley.

A’ndrea Elyse Messer | EurekAlert!
Further information:

More articles from Earth Sciences:

nachricht Receding glaciers in Bolivia leave communities at risk
20.10.2016 | European Geosciences Union

nachricht UM researchers study vast carbon residue of ocean life
19.10.2016 | University of Miami Rosenstiel School of Marine & Atmospheric Science

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

New method increases energy density in lithium batteries

24.10.2016 | Power and Electrical Engineering

International team discovers novel Alzheimer's disease risk gene among Icelanders

24.10.2016 | Life Sciences

New bacteria groups, and stunning diversity, discovered underground

24.10.2016 | Life Sciences

More VideoLinks >>>