Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Antarctic temperatures disagree with climate model predictions

A new report on climate over the world's southernmost continent shows that temperatures during the late 20th century did not climb as had been predicted by many global climate models.

This comes soon after the latest report by the Intergovernmental Panel on Climate Change that strongly supports the conclusion that the Earth's climate as a whole is warming, largely due to human activity.

It also follows a similar finding from last summer by the same research group that showed no increase in precipitation over Antarctica in the last 50 years. Most models predict that both precipitation and temperature will increase over Antarctica with a warming of the planet.

David Bromwich, professor of professor of atmospheric sciences in the Department of Geography, and researcher with the Byrd Polar Research Center at Ohio State University, reported on this work at the annual meeting of the American Association for the Advancement of Science at San Francisco.

"It's hard to see a global warming signal from the mainland of Antarctica right now," he said. "Part of the reason is that there is a lot of variability there. It's very hard in these polar latitudes to demonstrate a global warming signal. This is in marked contrast to the northern tip of the Antarctic Peninsula that is one of the most rapidly warming parts of the Earth."

Bromwich says that the problem rises from several complications. The continent is vast, as large as the United States and Mexico combined. Only a small amount of detailed data is available – there are perhaps only 100 weather stations on that continent compared to the thousands spread across the U.S. and Europe . And the records that we have only date back a half-century.

"The best we can say right now is that the climate models are somewhat inconsistent with the evidence that we have for the last 50 years from continental Antarctica .

"We're looking for a small signal that represents the impact of human activity and it is hard to find it at the moment," he said.

Last year, Bromwich's research group reported in the journal Science that Antarctic snowfall hadn't increased in the last 50 years. "What we see now is that the temperature regime is broadly similar to what we saw before with snowfall. In the last decade or so, both have gone down," he said.

In addition to the new temperature records and earlier precipitation records, Bromwich's team also looked at the behavior of the circumpolar westerlies, the broad system of winds that surround the Antarctic continent.

"The westerlies have intensified over the last four decades of so, increasing in strength by as much as perhaps 10 to 20 percent," he said. "This is a huge amount of ocean north of Antarctica and we're only now understanding just how important the winds are for things like mixing in the Southern Ocean." The ocean mixing both dissipates heat and absorbs carbon dioxide, one of the key greenhouse gases linked to global warming.

Some researchers are suggesting that the strengthening of the westerlies may be playing a role in the collapse of ice shelves along the Antarctic Peninsula.

"The peninsula is the most northern point of Antarctica and it sticks out into the westerlies," Bromwich says. "If there is an increase in the westerly winds, it will have a warming impact on that part of the continent, thus helping to break up the ice shelves, he said.

"Farther south, the impact would be modest, or even non-existent."

Bromwich said that the increase in the ozone hole above the central Antarctic continent may also be affecting temperatures on the mainland. "If you have less ozone, there's less absorption of the ultraviolet light and the stratosphere doesn't warm as much."

That would mean that winter-like conditions would remain later in the spring than normal, lowering temperatures.

"In some sense, we might have competing effects going on in Antarctica where there is low-level CO2 warming but that may be swamped by the effects of ozone depletion," he said. "The year 2006 was the all-time maximum for ozone depletion over the Antarctic."

Bromwich said the disagreement between climate model predictions and the snowfall and temperature records doesn't necessarily mean that the models are wrong.

"It isn't surprising that these models are not doing as well in these remote parts of the world. These are global models and shouldn't be expected to be equally exact for all locations," he said.

David Bromwich | EurekAlert!
Further information:

More articles from Earth Sciences:

nachricht UCI and NASA document accelerated glacier melting in West Antarctica
26.10.2016 | University of California - Irvine

nachricht Ice shelf vibrations cause unusual waves in Antarctic atmosphere
25.10.2016 | American Geophysical Union

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

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...

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

First results of NSTX-U research operations

26.10.2016 | Physics and Astronomy

UCI and NASA document accelerated glacier melting in West Antarctica

26.10.2016 | Earth Sciences

Ice shelf vibrations cause unusual waves in Antarctic atmosphere

25.10.2016 | Earth Sciences

More VideoLinks >>>