Earth Institute Researchers Present Their Work at the American Geophysical Union Fall Meeting

Scientists from The Earth Institute will arrive in San Francisco this week to attend the fall meeting of the American Geophysical Union (AGU), an annual gathering of more than 11,000 researchers from around the world who study the Earth and other planets. Representatives from the Lamont-Doherty Earth Observatory (LDEO), the Goddard Institute of Space Studies (GISS), the International Research Institute for Climate and Society (IRI) and many other affiliates of The Earth Institute will present a wide range of geologic, geochemical and interdisciplinary research, including the following:

The Katrina Disaster: A Poor World Tragedy in a Rich Country John Mutter, Deputy Director of The Earth Institute at Columbia University and his colleagues examined patterns of mortality along the Gulf Coast in the wake of Hurricane Katrina and found surprising similarities between that tragedy and the much larger catastrophe that occurred in poorer countries around the Indian Ocean one year ago. Poor populations within developing countries have long been recognized to be more vulnerable to natural disasters, but the same pattern has not been as apparent in the U.S. until Katrina.

Is there Still Time to Avoid ‘Dangerous Anthropogenic Interference’ with Global Climate? James E. Hansen, director of the GISS, examines how well humanity has responded to the warning inherent in the work of Charles D. Keeling, who passed away earlier this year. The now-famous Keeling Curve, which reveals both seasonal variability of CO2 in the Earth’s atmosphere as well as the growing effect human activity is having on atmospheric composition, has been hailed as the most rigorous and fundamental measure of global change. Hansen’s presentation will include the most current measures of the agents of global change and of climate change, including steps that have been taken to minimize and assess measurement bias. Ultimately, the metrics are beginning to paint an increasingly clear picture of humanity’s prospects for avoiding dangerous anthropogenic interference with the Earth’s climate.

Global Natural Disaster Risk Hotspots: Transition to a Regional Approach Art Lerner-Lam, director of the Center for Hazards and Risk Research at the Earth Institute, and his colleagues published Natural Disaster Hotspots: A Global Risk Analysis in 2005, which looked at the global distribution and occurrence of multiple natural hazards and the associated exposures of populations and their economic output. Lerner-Lam will present a summary of the findings of that report as well as suggested approaches for making the transition from a global analysis to more detailed regional and national studies. Several regional case studies will also be presented.

From Interoperability to Integration: Making Data and Information Accessible and Usable for Decision Making Recent natural disasters in both the developed and developing world have illustrated the many barriers that still exist in accessing environmental and socioeconomic data and in integrating such data to support decision making. Bob Chen of the Center for International Earth Science Information Networks (CIESIN) will report on recent efforts to improve data access across the so-called “digital divide,” to establish an “information commons” for science, and to improve the extent and quality of integrated databases to support decision making related to disaster management and environmental sustainability.

Global Mortality Risk Atlas: A Comparison of Two Global Disaster Risk Benchmarking Projects Silvia Mosquera Machado from IRI will present an overview of two global natural disaster risk benchmarking initiatives: the Disaster Risk Index developed by UNEP/GRID and the Natural Disaster Hotspots report produced by researchers at The Earth Institute and the World Bank. Her comparison converts the two mortality risk indices using geographical information systems (GIS) in such a way as to permit global, inter-country and inter-regional comparisons of risk.

Constraining the Rupture Length, Duration and Speed of the Great Sumatra-Andaman Earthquake Using Hydroacoustic Data Maya Tolstoy of LDEO examined recordings of the underwater noise generated by the December 26 earthquake in the Indian Ocean made by a network of hydrophones (underwater microphones) used to listen for the sound of nuclear weapons tests. Using the recordings, she and colleague Del Bohnenstiehl were able to accurately and quickly estimate the speed and length of the rupture and to identify two distinct phases within the entire event.

Relocation and Assessment of the December 2004 Sumatra-Andaman Great Earthquake Sequence and Background Seismicity Hannah Abend of LDEO and her colleagues reevaluated the location and depth of 3,200 earthquakes that occurred in the region of the December 26 Sumatra-Andaman Earthquake between January 1964 and May 2005. Their results show that the boundary between the Andaman microplate and the Burma subplate, which had been previously defined as a straight line, appears to be a step-like feature in the Earth’s crust, indicative of back-arc spreading in this region. In addition, they were able to determine that the subduction zone downgoing slab thickness ranges from about 25 to 35 km along the trench.

Post-Tsunami Reconstruction in Sri Lanka: Houses or Housing? Bijan Khazai of The Earth Institute and his co-authors look at efforts in Sri Lanka to reconcile the need for immediate shelter for victims of the December 2004 tsunami with the long-term perspective of rehabilitating livelihoods for coastal residents. Currently the national-level emphasis has been on providing housing divorced from questions of social and economic life, whereas at the district level, government agencies and NGOs have placed greater importance on creating social, human and financial capital. Their study also shows that there has been a general absence of mechanisms to incorporate community participation in decision-making and a general over-reliance on outside agencies.

The Impacts of the Indian Ocean Tsunami on Coastal Ecosystems and Resultant Effects on the Human Communities of Sri Lanka Jane Ingram and her colleagues examine the connections between social and ecological resilience that were revealed when the tsunami struck Sri Lanka last year. Before the tsunami, the coastal zone of Sri Lanka was inhabited by predominantly poor populations, most of whom were directly dependent on coastal natural resources. From observations in their and other recent studies, it becomes apparent that intact ecosystems played a vital role in reducing the impact of the tsunami and helping people rebuild their livelihoods afterwards.

Subduction and Accretion across the Ganges-Brahmaputra Delta: Is it Seismogenic? Leonardo Seeber and others from LDEO join Syed Humayun Akhter from the University of Dhaka in presenting the results of their analysis of the seismicity, geodesy, and geology of Ganges-Brahmaputra Delta region. They find evidence, both in historical and modern records, which point to the need to include the potential for large subduction earthquakes in hazard estimates for the region, which is along the same plate boundary that ruptured in the 2005 Sumatra-Andaman Earthquake.

Social Inequity and Risks Associated with Renewable and Conventional Energy Sources Jessika Trancik and her colleagues present the results of their study comparing the health and environmental risks associated with the widespread use of photovoltaic cells for electricity generation compared to those of common non-renewable options (coal, oil, gas and nuclear). Their findings pay particular attention to questions of social inequity related to extraction, operation and accidents, as well as climate change.

Urban Seismic Risk Perception and its Impact on Seismic Vulnerability in Unauthorized Housing Settlements of Istanbul, Turkey Unauthorized housing is a primary means of shelter in urban centers throughout the industrializing world. Rebekah Green of The Earth Institute looked at the relationship between unauthorized housing and its relationship to seismic risk in Istanbul, a city in more than 50 percent illegal housing. She finds that there is a critical need for scientists and engineers to engage residents of unauthorized housing and that residents are themselves able to quickly turn knowledge about hazards and vulnerability into actions that can reduce their own risk as well as the aggregate risk that urban centers face.

Combining Data from Bathymetry, Sub-Bottom Profiles, and Sediment Cores to Improve Sediment Budget and Accumulation Rates in the Hudson River Frank Nitsche of LDEO and his colleagues applied a combination of sediment analyses and sub-bottom profiling to image and characterize the bottom of the Hudson River Estuary from the town of Troy, N.Y. to New York Harbor. Their work illustrates the effectiveness of combining these various techniques in order to quantify the spatial extent and volume of sediment deposits, which is particularly important to know in places where dredging or pollution is an issue.

Assessment of Contaminant Transport in Waterways around Major Population Centers by Deliberate Gas Tracer Releases Pollution of urban waterways by toxic chemicals, sewage and fertilizer could threaten the health of local residents. David Ho of LDEO and colleagues used an inert gas tracer to assess the transport pathways and mixing regimes in New York Harbor, the East River, the Houston Ship Channel and the Stockton Deep Water Channel. In each experiment, the tracer acts as a proxy for contaminants, and the spread of the tracer was monitored for 7 to 10 days. Their work demonstrates the effectiveness of their technique for assessing contaminant transport, as well as the need to examine persistent or emerging events that could affect human health.

North American Drought Variability Reconstructed from Long Tree-Ring Records Ed Cook, director of LDEO’s Tree Ring Laboratory, reports on his reconstruction of drought in the western U.S. using a network of centuries-long annual tree-ring chronologies. He finds that past droughts of unprecedented severity occurred prior to A.D. 1300, which make the current western drought since 1999 pale in comparison. Climate model results by Richard Seager, also from LDEO, suggest that much of the observed North American drought variability is driven by changes in tropical Eastern Pacific sea surface temperatures. However, those results do not yet explain the duration of the epic droughts that occurred prior to A.D. 1300.

Spatiotemporal Land Cover Analysis of China Dust Storms using Remote Sensing Imagery Dust storms are a persistent problem in East Asia that have a serious impact on major metropolitan areas and agricultural regions. More than 60 moderate to heavy dust storms have affected this region over the past 40 years, brought on from large-scale high velocity winds, anthropogenic influences, and decreased vegetation. Dalia Bach of LDEO and her colleagues present a study using remote sensing imagery to examine spatial and temporal trends in vegetation and relate these to land-cover dynamics and dust-storm frequency.

Game Theoretic Modeling of Water Resources Allocation under Hydro-Climatic Uncertainty Casey Brown of IRI reports on work he and his colleagues have done that suggest game theory is uniquely suited to modeling equity aspects of water resource allocation in an uncertain hydrological/climatological environment. Game theory is a method of economic modeling that incorporates decision-making of individual actors within a system based on self-interest. With respect to water allocation, a game theory model could be used in conjunction with a hydro-climate model to study how water allocation decisions might be made in an uncertain environment and how these decisions would impact society as a whole.

Interhemispheric Correlation of Glacial Terminations Using In-situ Be-10 Joerg Schaefer of LDEO presents his and his colleagues’ findings related to the use of beryllium-10 (Be-10) as a marker to trace the extent and retreat of the world’s glaciers and, therefore, to study global climate change. Their work suggests that the timing of last deglaciation is remarkably consistent throughout the northern and southern hemispheres and appear to be largely driven by a near-global rise in summer temperatures after the last glacial maximum, a fact hidden by the winter-dominated Greenland ice core record. Schaefer, Vincent Rinterknecht and Meredith Kelly, also of LDEO, will present individual studies using Be-10 to track the retreat of glaciers from the Lower Hudson Valley and the western and eastern margins of the Greenland Ice Sheet.

The Neodymium Isotopic Composition of Past North Atlantic Deep Water: First Results from Deep-Sea Corals Tina van de Flierdt and her colleagues present their results using samples of deep-sea corals to measure the neodymium (Nd) isotope ratios of past seawater in an effort to understand the role of deep water circulation in rapid climate change. Their coral samples provide information on deep-and intermediate-seawater chemistry dating back to 92,000 years before present. Initial results suggest that the Nd isotope ratios of North Atlantic seawater were similar during the last Ice Age to the present day, a finding that substantiates the use of this novel tracer system in paleoclimate research.

Oceanographic Conditions at the Larsen B Ice Shelf Front before and after the 2002 Breakout Bruce Huber of LDEO and his colleagues report on observations made immediately before and after the Larsen B ice shelf in the northwestern Weddell Sea experienced a catastrophic breakout in early 2002. The breakout resulted in a large, open-water embayment in the region formerly covered by shelf ice. At several locations along the remaining ice fronts there is evidence of sub-freezing Ice Shelf Water (ISW) plumes emanating from beneath the ice shelf and observations in 2005 indicate that some of these plumes may be carrying glacial debris.

Ridge Flank Crustal Systems: Potential for Permanent Sequestration of Anthropogenic Carbon Dioxide on the Juan de Fuca Plate¹ Potential of Basalt Aquifers for the Permanent Sequestration of Anthropogenic Carbon Dioxide² David Goldberg¹ and Jurg Matter², both of Lamont-Doherty, present feasibility studies of basaltic formations as potential environments for future long-term storage of human-generated carbon dioxide. Questions that must be addressed in order to determine the potential for a site to be used include the chemical and physical make up of the storage formation, as well as the potential for it to hold as much as 22 billion tons of carbon dioxide per year (6 billion tons/year of carbon). Studies by the Integrated Ocean Drilling Program (IODP) suggest that basalt aquifers and regions of the Juan de Fuca ridge plate in the eastern North Pacific may be likely candidates.

Co-Located Observations with High-Rate GPS and Accelerometers on the Verrazano-Narrows Bridge: An Example of Synergism in Geophysical Methods Andrew Smyth of Columbia University, Mikhail Kogan of LDEO and their colleagues have combined seismologic monitoring techniques with global position systems (GPS) to measure the effect that traffic, thermal expansion and tens of thousands of runners in the New York City Marathon have on the Verrazano-Narrows Bridge. Following the Sumatra-Andaman Earthquake, similar instruments detected long-period surface waves thousands of kilometers away from the epicenter. Both results suggest that proper permanent deployment of GPS antennas and communication equipment would make it possible to measure sub-centimeter movements of bridges in real-time.

Evidence from an Ice Core of a Large Impact circa 1443 A.D. Dallas Abbott of Lamont-Doherty and her colleagues analyzed melt water from nine samples taken from the West Antarctic Siple Dome ice core that date between 1440 and 1448 A.D. and found high values of potassium and calcium as well as impact glass, microcrystaline magnetite, minerals and five microfossils corresponding to the 1443 A.D. level. These data appear to correspond with the timing and effects of an impact that produced a 24km crater on the southern New Zealand shelf and that may have resulted in tsunami run-ups of as much as 130m in Jervis Bay Australia.

Lamont-Doherty Earth Observatory

Goddard Institute for Space Studies

The International Research Institute for Climate and Society (IRI)

Center for International Earth Science Information Network (CIESIN)