Research Title: Long-Term Environmental Change
Funding Level (millions of dollars):
Committee on Environment and Natural Resources (CENR) Component:
(a) Subcommittee: Subcommittee on Global Change Research (100%)
(b) Environmental Issue: Climate Change (10%); Natural Variability (90%)
(c) Research Activity: System structure and function: Observing (50%); Understanding (50%)
National Museum of Natural History (NMNH)
Smithsonian Tropical Research Institute (STRI)
Point of Contact:
Ted A. Maxwell
Understanding anthropogenic modifications to the environment can be done only if we know the natural variability of the systems. The primary thrust of the Smithsonian's work is to improve our knowledge of the natural processes involved and to continue to provide a long-term repository for present and future studies. Study of "deep history" makes three unique contributions to global change research. Biotic, geologic, and climate systems experience natural fluctuations over decades to 105 years; therefore only retrospective studies that consider very long time periods have a hope of distinguishing signal from noise, and of establishing pre-human baseline conditions. Fossils and sedimentary rocks directly record the impact of past global climate change on ecological systems, providing the only examples we have of these phenomena and their effects. Finally, paleontological and geological data are critical, and only, test of computer-based simulations of past climate conditions, and so they play an important role in refining models of climate dynamics. This program addresses most of the research priorities outlined in the GCRP under Earth System History. Paleoclimate and paleoecology are explicit foci of research, as are past changes in ocean circulation, ocean productivity, and sea level.
Studies in Paleoecology are largely based on a unique resource of the Smithsonian, its collections, which range from Paleontological specimens used to infer growth rates of species to botanical specimens that are a baseline for modern studies. We have established an international network of collaborating scholars at private and governmental institutions. We have sponsored and hosted international meetings and a symposium addressing the issue of ecosystem stability on long and short time scales. Strong linkages exist to research at USGS and Smithsonian bureaus, as well as to those working under NSF support at many private universities and museums.
We have preliminary data suggesting that past ecosystems may have displayed "threshold" effects; they showed little response to climate change over long periods, then changed rapidly over short intervals. We will concentrate studies on the rates of change, a largely unknown factor in the environment variability, continue studies of world's deltas, with emphasis on sea level change and fluvial response, continue work on a volcano data base and link to other shared environmental archives.
Long-term indicators of environmental change area studied at NMNH to understand the natural processes and rates of ecological, oceanographic and volcanic phenomena as they affect the global environment, and at STRI to determine anthropogenic and other ecosystem responses to climate change. NMNH Studies of Long Term Climate Change (100%). These studies concentrate on the detection of past climate changes on ecological systems, examination of past episodes of warmer climates to establish pre-human baseline conditions, determination of ecosystem response to sudden environmental change, and are used to test computer predictions of paleoclimate. This work is performed through field research and by using the extensive collections of fossils and other data available through the museum, and methods are being developed to link a customized data management program to a graphics/map interface. Recent results include the documentation of the effect of sea level rise on coral reef growth, of pre-historic human colonization on island biotas, and of climate on vegetational diversity and structure. The Nile Delta Project, underway since 1985, seeks to identify paleoclimate changes through their effects on the Nile drainage system, both on the delta and adjacent coastlines. Major ecological changes due to man (via the Aswan High Dam that modified irrigation and sedimentation), natural forces (salt water incursion and land subsidence), and desertification (changing the sediment load of the river) are being studied employing the sediment record in the Nile delta and adjacent coastlines. This work has been expanded to include other deltas of the world. Also at NMNH, the historical record of volcanic events on a global scale is continuously updated and made available to the scientific community via the Global Volcanism Network (formerly the Scientific Event Alert Network, SEAN). A database of the world's volcanoes and their eruptions over the last 10,000 years is maintained, as is an archive of maps, photographs and other documentation. The database has been an active project for more than 25 years, and forms the natural baseline for studies such as those dealing with the construction of volcanic aerosols to global warming. At STRI, we are proposing a program to core lakes in the Amazon basin in order to determine long-term changes in vegetation associated with Pleistocene climate changes in the tropics.
To understand long-term indicators of global change present in the historical artifacts and records of the museums as well as in the geologic and botanical record at field sites.