15–19 December 2008

NSIDC experts present new research at American Geophysical Union (AGU) Fall Conference

NSIDC experts presented posters and oral presentations on new research concerning changing permafrost, Arctic amplification, the international challenges that come with loss of Arctic sea ice, and more in December 2008 at the AGU conference. Please contact the NSIDC Press Office for more information about the presentations or speakers highlighted below: +1 (303) 492-1497 or srenfrow@nsidc.org.

We offered information on new and updated data sets and tools, data resources for cryospheric and Earth science researchers, and information for journalists, educators, and the general public at our booth number 2052.

Climate, Permafrost, and Landscape Interactions on the Tibetan Plateau (Tingjun Zhang, NSIDC Senior Research Scientist, invited oral presentation GC11B-02)

Observational records show that climate warming has been underway on the Qinghai-Tibetan Plateau in China for the past few decades. Our preliminary findings suggest that local land-cover/land-use change and human activities may substantially contribute to the observed climate warming on the Plateau, with subsequent impacts on permafrost and climate feedbacks.

Arctic Sea Ice in 2008: Standing on the Threshold (Mark Serreze, NSIDC Director Elect and Senior Research Scientist, invited oral presentation U24B-01)

Perhaps the most visible sign of global climate change is the Arctic's rapidly shrinking sea ice cover. Concerns are growing that we are approaching a “tipping point,” beyond which there is rapid transition to an ice-free Arctic Ocean in summer. Sea ice extent in September 2007 was the lowest recorded over the satellite era, and likely the lowest in at least a century. Could summer 2007 have been the tipping point? And what was the significance of the second-lowest extent set in September 2008?

Estimating Terrestrial Wood Biomass from Observed Concentrations of Atmospheric Carbon Dioxide (Kevin Schaefer, NSIDC Research Scientist, poster presentation B33A-0399)

Biomass harvesting, fires, and other disturbances lead to a long-term net sink of atmospheric carbon dioxide from biomass. However, because of a lack of global observations, most terrestrial carbon cycle models assume that biomass is in a steady state. Using a terrestrial carbon cycle model and an atmospheric transport model, we estimate global maps of wood biomass consistent with observed atmospheric carbon dioxide concentrations.

Emerging Arctic Amplification as Seen in the NCEP/NCAR Reanalysis (Julienne Stroeve, NSIDC Research Scientist, poster presentation C41B-0502)

Rises in surface air temperature in response to increasing atmospheric greenhouse gas concentrations will be larger in the Arctic compared to the Northern Hemisphere as a whole. This concept is known as Arctic amplification; models indicate that Arctic amplification will be focused over the Arctic Ocean. Recent observations of conditions over the Arctic Ocean are consistent with model-projected Arctic amplification associated with declining sea ice, suggesting that we may be seeing the emergence of Arctic amplification.

A Reconstructed 1784–2007 Time Series of Greenland Melt Extent (Oliver Frauenfeld, NSIDC Research Scientist, oral presentation C44A-08)

Total melt on the Greenland ice sheet has been rising over the past several decades, with 2007 melt extent setting a new record. We developed a reconstructed history of annual Greenland melt extent from the late 1700s to 2007 using relationships between historical temperature/circulation observations and ice melt. This reconstruction puts 2007 into a historical perspective. The reconstruction indicates that if the current trend toward increasing melt extent continues, total melt across the Greenland ice sheet will exceed historic values of the past two and a quarter centuries.

Impacts of Declining Arctic Sea Ice: An International Challenge (Mark Serreze, NSIDC Director Elect and Senior Research Scientist, invited oral presentation C51B-01)

Recognition is growing that ice loss will have environmental impacts that may extend well beyond the Arctic. What are the major national and international research efforts focusing on the multifaceted problem of declining sea ice? What are the areas of intersection, and what is the state of collaboration? How could national and international collaboration be improved? This talk will review some of these issues.

Synoptic-scale Atmospheric Forcing of Frozen Ground in the Eurasian High Latitudes (Oliver Frauenfeld, NSIDC Research Scientist, oral presentation C52A-04)

Seasonal freezing and thawing of frozen ground plays an important role in ecosystem diversity, productivity, and the Arctic hydrologic system. Long-term changes in seasonal freeze and thaw depths are useful indicators of climate change, but previous assessments only looked at data from 1956 to 1990. Here, we update the assessment through 2000 to include a decade that experienced accelerated climate warming. We find a statistically significant overall change in seasonal freeze depth. We also note that a prominent decrease in freeze depths from 1970 to 1995 appears tied to the North Atlantic Oscillation.

Arctic atmospheric circulation and surface air temperature anomalies: Are the rules changing? (Andy Barrett, NSIDC Research Scientist, oral presentation C53A-07)

Relationships between atmospheric circulation and temperature in the Arctic appear to be changing. The past five years have seen record or near-record sea ice lows and strong positive temperature anomalies over the Arctic Ocean in autumn. We compare recent and past autumns that have similar atmospheric circulation patterns to gain insight into emerging Arctic amplification.

Link to NSIDC webpage: http://nsidc.org/news/events/agu_2008/