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A potential source of large volumes of greenhouse gas is the methane naturally produced and stored in Arctic environments. Naturally formed methane occurs in Arctic wetlands, frozen in permafrost, and is trapped in Arctic sediments as methane hydrate, a solid compound consisting of a methane molecule surrounded by ice. Should Arctic temperatures or sea level rise, as the global warming theory suggests will happen, methane stored in the Arctic could be released and further increase the concentration of greenhouse gases in the atmosphere. The USGS is studying the formation, amount, and distribution of

methane in Arctic permafrost, wetlands, and sediments to assist in estimating the potential for methane release to the atmosphere in response to regional or global environmental change.

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Providing Data and Information

The

The complexity of global change requires that many types of data and information from a variety of scientific disciplines be available to conduct research, manage natural resources, educate the public, and make informed policy decisions. Large quantities of data and information must be assembled, documented, archived, and disseminated to meet the demand of the scientific community. It is equally important to provide data bases and communicate research results outside the scientific community as a basis for decisionmaking and public education.

The USGS is working with other Federal agencies to develop the Global Change Data and Information System to improve access to data and information. As part of this effort, the USGS is preserving the 21-year archive of data from

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Interactive GLIS browse screen showing an advanced very high resolution radiometer (AVHRR) satellite image of the eastern Mediterranean and Red Sea areas. For direct-dial access, modem settings should be at 8 bits with no parity and 1 stop bit, then dial (605) 594-6888. For network access, telnet to the Internet address glis.cr.usgs.gov on any standard computer terminal.

the Landsat series of Earth-observing satellites and making these data available to the public in useful formats. The Global Land Information System (GLIS), showcased at the United Nations Conference on Environment and Development in Rio de Janeiro in 1992, can be used to learn about these data and their availability. GLIS is a "user friendly” interactive computer-based system that provides information about global land data sets and how to obtain them. It can be accessed via computer modem from remote locations throughout the world. The system is based at the USGS EROS Data Center in Sioux Falls, S. Dak.

CD-ROM technology is offering another significant improvement in archiving and disseminating global change data by providing an inexpensive means of offering large regional, continental, and global data sets. New CD-ROM products available from the USGS include the Hydro-Climatic Data Network, which provides historical streamflow data for sites throughout the United States and its Territories, 10-day preprocessed global AVHRR data, and the land-cover characteristics data base, which includes information reflecting selected seasonal vegetation changes, along with elevation, soils, and climate data for the conterminous United States. These data bases provide the "real-world" basis for predictive modeling, which is needed for solving the problems associated with global climate change.

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data used for running the models. Improving the reliability of model simulations of future global change depends on reducing uncertainties about the processes operating within each of the Earth's critical environmental systems and how these systems interact to regulate the global climate.

GCM's must incorporate mathematical representations of the movement of energy, water, and carbon between the land, atmosphere, and oceans. USGS participation in global modeling activities includes simulations of past climates, detailed descriptions of the land surface, and improvements in the mathematical representation of hydrologic processes and terrestrial environments. Land characterization and surface hydrology are critical to predicting climate, water resources availability, agricultural productivity, ecosystem change, and

Gunnison River Basin
Study

In the Gunnison River basin of Colorado, a modeling framework for coupling atmospheric, hydrologic, and water management variables has been developed in cooperation with the Bureau of Reclamation. In the spring of 1993, this model enabled the bureau to regulate flow from dams on the Gunnison more effectively and thereby avoid downstream flood hazard during the spring snowmelt season. Other techniques and models are being developed for estimating impacts such as desertification and changes in permafrost. Understanding the potential impacts of global change in arid and cold regions is especially important, because these fragile environments would in many instances be the first to show the impacts of climate change. Because of this sensitivity, the study of arid and cold regions is important to the early detection of global change. As the case of methane in the Arctic indicates, climate change in cold regions could even trigger processes causing further environmental change.

desertification. The USGS is providing modelers with high-quality data sets that allow for more accurate representations of current environmental conditions in GCM's and other models of terrestrial processes. USGS scientists are developing techniques and data sets that integrate information about contemporary environmental systems, using Landsat and National Oceanic and Atmospheric Administration satellite data, along with a variety of ground-based information.

Improved understanding of the impacts of climate change on people and on ecological systems also depends on having better models at landscape, watershed, and regional scales that are relevant to resource managers. USGS global change research has developed improved analytical methods and modeling procedures for evaluating the sensitivity of land and water resources to global change. These techniques help quantify the potential impacts of change and have already helped to solve watermanagement problems in the Delaware River Basin, the Gunnison River basin of Colorado, and the American and Carson River basins of California and Nevada.

The USGS is participating in the development of a multiagency laboratory for Terrestrial Ecosystems Regional Research and Analysis (TERRA) located

in Ft. Collins, Colo. The TERRA laboratory is developing analytical techniques that realistically incorporate land and natural resource management considerations into the components of global computer models that represent terrestrial ecosystems.

USGS global change research has developed improved analytical methods and modeling

procedures for

evaluating the sensitivity of land and water resources to global change.

Through this balanced program of ground-based observations and remote sensing, process studies, data management, and modeling, all based on longterm experience in earth-science research, the USGS is contributing information needed by the Nation to assess the causes and consequences of global change.

USGS global change research is coordinated by a multidisciplinary team whose combined experience spans the technical expertise of the entire bureau.

For more information on USGS global change research, contact:

Telephone (703) 648-4450
Internet mdcarr@usgs.gov

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