The weekly NOON BALLOON lecture series provides undergraduates in the Earth and environmental sciences, and anyone else who is interested, a look at the breadth of research being conducted in these fields. Lecturers are research scientists/faculty and graduate students who will talk about their current research and how it ultimately contributes to the understanding of our planet.
Spring 2010 Schedule
Tuesdays 12:15-1:00pm in Room 417 Schermerhorn Hall
You are welcome to bring your lunch.
Peter deMenocal - When Climate Made Us: African Climate and Human Evolution
Summary: The fossil record of early human evolution in Africa is punctuated by bursts of exceptional evolutionary change that eventually produced uniquely human traits - bipedality, large brains, and tool use. With new and diverse paleoclimate data, we'll test the hypothesis that these biotic changes were related to progressive shifts in African climate toward drier and increasingly variable conditions.
Wallace Broecker - Will the ongoing CO2 buildup cause a severe drying of the western U.S.?
Summary: Based on the record for the last 25 K yrs kept in closed basin lakes, stalagmites and polar ice, the earth's hydrologic cycle shifts in union as the earth's temperature and the interhemispheric temperature difference changes. Based on this evidence, the American west will experience a severe drying as CO2 builds up in our atmosphere.
John Mutter - (When) do natural disasters matter?
John Flynn - Exploration of the Chilean Andes: Evolution of South American Mammals, Environments, and Mountains
Summary: South America was an island continent for most of the past 80 million years, from its separation from most other Pangean landmasses in the Late Cretaceous until the beginning of its full reconnection with North America via the Isthmus of Panama during the Pliocene. This long-term isolation produced a highly peculiar terrestrial biota, the paleontologically best known component of which is a diverse array of native mammals (marsupials, edentates, primates, rodents, and numerous ‘ungulate’ groups). Recently discovered deposits in the Andes Mountains of Chile, containing terrestrial mammal fossils, together with multidisciplinary studies of classical sequences, have yielded new insights into the biotic and environmental history of South America. Notable advances include documentation of the oldest mammalian faunas dominated by grazing taxa (suggesting the appearance of grasslands at least 15 million years earlier than on other continents), evidence of early biogeographic provinciality within South America, and substantial revisions to understanding of Andean uplift history.
Mark Anders - The Yellowstone Supervolcano
Summary: Over the last 2 million years Yellowstone has experienced three of the most violent volcanic eruptions in Earth's history. What causes these eruptions? How often do they occur? What would be the effects of one of these eruptions if it happened today? Is it possible to predict an eruption? These are some of the questions that will be addressed in the talk.
Jerry McManus - Ocean circulation and abrupt climate change
Summary: Interconnected ocean currents move water, salt, and heat around the Earth today, influencing the global climate. Paleoceanographic evidence suggests that this current system was different in the past, and that changes in its strength and configuration were associated with the dramatic climate changes of the ice ages. Yet other large climate influences, like the seasonal amount of sunlight, and atmospheric greenhouse gas concentrations, often varied at the same time, making it hard to isolate the primary cause. We'll consider some new and existing "proxy" evidence from deep-sea sediments that shifting ocean currents did indeed seem to drive dramatic climate change, especially in and around the North Atlantic Ocean. Could it happen again?
Sidney Hemming - Ashes, Ashes, All Fall Down
Summary: The presence of volcanic ashes interlayered in sediments and sedimentary rocks provides relative time lines that allow geologists to confidently correlate non-continuous deposits. Geochronologists use these deposits to make estimates of the absolute time lines. Significant developments in the past decade in both 40Ar/39Ar and U-Pb radio-isotopic chronometry allow unprecedented levels of precision for dating volcanic layers, and it is now possible to evaluate rates of geological and climate change and provide calibrations for major biological events in deep time. Improved precision for each chronometer has also highlighted important limitations on accuracy and precision that make the development of a multi-chronometer timescale challenging. The EARTHTIME initiative is focused on resolving these limitations (research opportunities!). I will talk about some of the applications of volcanic ash deposits for studying geological processes and events.
Kevin Griffin - Arctic Warming: How might climate change effect the growth of tundra plants?
Summary: How do Arctic plants cope with the harsh environmental conditions that they experience? During the short (~75 day) Arctic growing season, temperatures are cool and quite variable, the soil is frozen not far below the surface, and the sun never sets! Despite these challenges and the relatively small stature of the plant communities, over the last tens of thousands of years these ecosystems have locked away as much carbon in their frozen soils as currently exists as CO2 in the atmosphere. Today the Arctic is experiencing dramatic warming and important widespread ecological changes are being observed. We would like to understand how plant respiration, which returns carbon to the atmosphere, responds both to the unusual arctic condition of constant daylight during the growing season and to the rapidly changing climate. I will present results, collected by myself and several Columbia University students, at the Toolik Lake Long-Term Ecological Research Site, located on the North Slope of the Brooks Range in the Alaskan Arctic.
Natalie Boelman - Tundra is Burning! Estimating Burn Severity from Satellites
Summary: Because tundra fires have been infrequent, small and of low burn severity in the recent past, little effort has been made to use remote sensing to study them. However, documented increases in shrub abundance, coupled with projected low effective moisture conditions, suggest that wildfires in tundra are expected to increase in both frequency and area burned throughout the Low Arctic region as global warming continues. In this study, we determine if tundra burn severity can be effectively estimated and mapped using spectral vegetation indices, which index (NBR, NDVI and EVI2) is best suited to do this, and how pixel size (MODIS, Landsat, Quickbird sensors) influences mapping and classification.
Mark Cane - Climate in the Currents of History
Summary: We take a tour of some of the impacts of climate variations on human history, beginning with the origins of agriculture in the Middle East. We will consider historical droughts in North America, especially the Dustbowl drought of the 1930s, and then examine the analogous but more severe droughts some seven centuries earlier and their possible role in the demise of the Anasazi. Ideas about the physical climate mechanisms responsible for these droughts will be presented. We will consider the modern and ongoing drought in the Sahel, and its impact on Darfur, before taking up the projections of drought in the warming world ahead of us.