Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

34 Million-Yr GHG Model: Earth Is CO2 Sensitive

20.10.2008
In a new model of atmospheric carbon dioxide levels, sea level variation, Northern Hemisphere ice sheets and Antarctic ice over the past 34 million years reported in Nature, University of Massachusetts Amherst climatologist Robert DeConto and colleagues at four other institutions cast new light on estimates of polar ice volume and the relationship to sea level. Their model has implications for understanding future effects of global warming.

Climatologist Robert DeConto of the University of Massachusetts Amherst and colleagues at four institutions are reporting in the Oct. 2 issue of the journal Nature that their latest climate model of the Northern Hemisphere suggests conditions would have allowed ice sheets to form there for the last 25 million years, or about 22 million years earlier than generally assumed.Their research has implications for the evaluation of global climate change.

When climate and ice sheet models of the past closely match other information, in this case sea-level data, climate scientists gain more precise tools for predicting future trends. “There’s a lot of mysterious sea-level variability over the last 25 million years that is difficult to explain with Antarctic ice alone,” DeConto says. “But if ice sheets and glaciers were present earlier in the Northern Hemisphere, as we think they might have been, they might provide the answer.”

With future CO2 levels expected by the year 2100 to approach levels not seen in the last 25 million years, understanding past conditions is crucial for predicting possible implications for Earth’s ice sheets and sea levels. “It’s important that we get this right,” DeConto says. “If we are correct, we are rewriting the history of the cryosphere over the past 34 million years and calling a lot of things into question. It’s a challenge to geologists.” The cryosphere is the planet’s total amount of snow, ice and frozen ground.

The new model, accounting for atmospheric CO2 and changes in Earth’s orbit around the sun among other variables, shows that the threshold of atmospheric CO2 at which large ice sheet development in the Northern Hemisphere is possible, is much lower than for Antarctica. The work, supported by the National Science Foundation, also suggests that climate, ice sheets and sea level may be far more sensitive to CO2 levels than generally accepted.

“The last time CO2 levels were as high as they are expected to reach in coming centuries, there was no big ice sheet on Antarctica because the planet was too warm,” DeConto says. “This is not to say that we’ll see the great East Antarctic Ice Sheet melt, because its large size and high elevations are self-sustaining. But it is alarming. We are trying to understand exactly what the effect of those high CO2 levels will be. It appears there will be an associated rise in sea level because much of the rest of the world’s ice cover could be affected.”

In addition to DeConto, the team includes climate researchers from Penn State University and Yale University in the United States and the University of Southampton and Cardiff University in Great Britain. Their paper published today is accompanied by an invited commentary by geologist Stephen Pekar of Queens College, New York, an expert on ancient sea level variation over the same period. He notes that DeConto and colleagues’ results not only address the long-standing debate among geologists about the cause of ancient sea level fluctuations, but they are “relevant to today’s discussions about climate change.”

In an earlier paper, DeConto and colleagues had showed that global cooling which began about 34 million years ago during the “greenhouse to icehouse transition” was probably related to declining greenhouse gas levels and less to ocean currents around Antarctica as once believed.

Rob DeConto | Newswise Science News
Further information:
http://www.umass.edu
http://www.geo.umass.edu

Further reports about: Antarctic Antarctica CO2 Hemisphere atmospheric CO2 global warming greenhouse ice sheet sea level

More articles from Ecology, The Environment and Conservation:

nachricht Successful calculation of human and natural influence on cloud formation
04.11.2016 | Goethe-Universität Frankfurt am Main

nachricht Invasive Insects Cost the World Billions Per Year
04.10.2016 | University of Adelaide

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

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

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

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

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>