What're you doing on Friday? There are two excellent-sounding earth science seminars inside the Beltway: The University of Maryland Geology Department's weekly seminar, and the American Meteorological Society's monthly seminar for policy makers. Both events are free and open to the public. AMS is at 10am, UMD at 11am. You can't do both -- you must choose...

AMS: Friday, September 26, 2008New Time - 10:00 AM - 12:30 PM
Dirksen Senate Office Building, Room G50 Washington, DC

Accelerating Atmospheric CO2 Growth from Economic Activity, Carbon Intensity, and Efficiency of Natural Carbon Sinks

What is the relationship between economic activity and CO2 growth? What is carbon intensity and how does it relate to economic activity? What are the trends in CO2 growth, carbon intensity, and changes in the efficiency of natural reservoirs to store carbon? How does the growth in CO2 compare to the various estimates of CO2 growth contained in the most recent IPCC assessment of climate change? What is permafrost and what is the extent of permafrost thaw in the Arctic? Is permafrost thaw a response to global warming and if so, what is the future likely to hold? Will permafrost thaw result in the release of additional CO2 into the atmosphere from Arctic soils? If so, what is the impact likely to be on global warming? How much carbon is stored in Arctic soils? Assuming that the Arctic continues to warm well above the global average, what is the likely fate of that soil carbon and how might it influence climate in the future?

Public Invited; Buffet Reception Following

Moderator: Dr. Anthony Socci, Senior Science Fellow, American Meteorological Society

Speakers:

• Dr. Josep (Pep) Canadell, Executive Director, Global Carbon Project, Commonwealth Scientific and Industrial Research Organization (CSIRO) Marine and Atmospheric Research, Canberra, Australia
• Dr. Vladimir Romanovsky, Geophysical Institute, University of Alaska, Fairbanks, A
• Dr. Howard E. Epstein, Department of Environmental Sciences, University of Virginia, Charlottesville, VA

Program Summary

How Fast is Atmospheric CO2 Growing and Why, and Does it Suggest Ways to Mitigate Climate Change?

The increase in atmospheric carbon dioxide (CO2) is the single largest human perturbation of the climate system. Its rate of change reflects the balance between human-driven carbon emissions and the dynamics of a number of terrestrial and ocean processes that remove or emit CO2. It is the long term evolution of this balance that will determine to a large extent the speed and magnitude of climate change and the mitigation requirements to stabilize atmospheric CO2 concentrations at any given level. Dr. Canadell will present the most recent trends in global carbon sources and sinks, updated for the first time to the year 2007, with particularly focus on major shifts occurring since 2000. Dr. Canadell’s research indicates that the underlying drivers of changes in atmospheric CO2 growth include: i) increased human-induced carbon emissions, ii) stagnation of the carbon intensity of the global economy, and iii) decreased efficiency of natural carbon sinks.

New Estimates of Carbon Storage in Arctic Soils and Implications in a Changing Environment

The Arctic represents approximately 13% of the total land area of the Earth, and arctic tundra occupies roughly 5 million square kilometers. Arctic tundra soils represent a major storage pool for dead organic carbon, largely due to cold temperatures and saturated soils in many locations that prevent its decomposition. Prior estimates of carbon stored in tundra soils range from 20-29 kg of soil organic carbon (SOC) per square meter. These estimates however, were based on data collected from only the top 20-40 cm of soil, and were sometimes extrapolated to 100 cm. It is our understanding that large quantities of SOC are stored at greater depths, through the annual freezing and thawing motion of the soils (cryoturbation), and potentially frozen in the permafrost.

Recent detailed analysis of Arctic soils by Dr. Epstein and his colleagues found that soil organic carbon values averaged 34.8 kg per square meter, representing an increase of approximately 40% over the prior estimates. Additionally, 38% of the total soil organic carbon was found in the permafrost.

A total of 98.2 gigatonnes (1015 grams) of carbon is estimated to be stored in the soils of the North American Arctic tundra. An area-based estimate for the entire Arctic suggests the presence of approximately 160 gigatonnes of carbon. The annual increase in atmospheric carbon dioxide is roughly 2% of this amount, so small changes in Arctic carbon storage could have substantive impacts on atmospheric CO2. The future of this stored carbon is, however, largely uncertain in the face of a changing Arctic environment. Climate change and resulting increasing temperatures in much of the Arctic could increase the decomposition rates of soil organic carbon (producing atmospheric CO2), and increase permafrost thaw, which would expose more soil organic carbon for decomposition. On the other hand, increasing temperatures could also lead to greater sequestration of atmospheric CO2 by tundra vegetation. Actual changes will be the result of complex interactions between processes that sequester carbon and those that release it.

Past, Present and Future Changes in Permafrost and Implications for a Changing Carbon Budget

Presence of permafrost is one of the major factors that turn northern ecosystems into an efficient natural carbon sink. Moreover, a significant amount of carbon is sequestered in the upper several meters to several tens of meters of permafrost. Because of that, the appearance and disappearance of permafrost within the northern landscapes have a direct impact on the efficiency of northern ecosystems to sequester carbon in soil, both near the ground surface and in deeper soil layers. Recent changes in permafrost may potentially transform the northern ecosystems from an effective carbon sink to a significant source of carbon for the Earth’s atmosphere. Additional emissions of carbon from thawing permafrost may be in the form of CO2 or methane depending upon specific local conditions.

Dr. Romanovsky will present information on changes in terrestrial and subsea permafrost in the past during the last glacial-interglacial cycle and on the most recent trends in permafrost in the Northern Hemisphere. He will further discuss the potential impact of these changes in permafrost (including a short discussion on potential changes in methane gas clathrates) on the global carbon cycle. Dr. Romanovsky’s research suggests that permafrost in North America and Northern Eurasia shows a substantial warming during the last 20 to 30 years. The magnitude of warming varied with location, but was typically from 0.5 to 2°C at 15 meters depth. Thawing of the Little Ice Age permafrost is on-going at many locations. There are some indications that the late-Holocene permafrost started to thaw at some specific undisturbed locations in the European Northeast, in the Northwest and East Siberia, and in Alaska. Future projections of possible changes in permafrost during the current century, based on the application of calibrated permafrost models, will be also presented.

The next seminar is tentatively scheduled for October 10, 2008.
Topic: Ecosystem Health in a Rapidly Changing Climate

Please see the AMS web site for seminar summaries, presentations and future
events: http://www.ametsoc.org/seminar

For more information please contact:
Anthony D. Socci, Ph.D. Tel. (202) 737-9006, ext. 412 socci@ametsoc.org

UMD: 11:00am - 12:00pm at 1121 Computer Science Instructional Center

Internal flow and extrusion of the Greater Himalayan Slab, Mount Everest Massif: a tour of the world's highest rocks
Dr. Rick Law from Virginia Polytechnic Institute and State University

If you are interested in meeting with Dr. Law please sign up online. You also may delete an appointment from this page. Please join the faculty and students for refreshments in the Geology Building foyer at 10:30 am.

Seminar series web page for UMD-College Park Geology.

Labels: climate change, CO2, geology, global warming, maryland, meetings