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 Waste in the water – New purification techniques for healthier aquatic ecosystems
24.07.2018 | Eberhard Karls Universität Tübingen

nachricht Plenty of habitat for bears in Europe
24.07.2018 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig

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: Color effects from transparent 3D-printed nanostructures

New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference

Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

Im Focus: The “TRiC” to folding actin

Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.

Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

LaserForum 2018 deals with 3D production of components

17.08.2018 | Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

 
Latest News

Smallest transistor worldwide switches current with a single atom in solid electrolyte

17.08.2018 | Physics and Astronomy

Robots as Tools and Partners in Rehabilitation

17.08.2018 | Information Technology

Climate Impact Research in Hannover: Small Plants against Large Waves

17.08.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>