Geoscience Reference
In-Depth Information
The Environment
With the increase in world population, the Earth has seemingly shrunk from a
vast realm of unspoiled lands and seas to a small blue planet with limited
resources for sustaining human activities. Environmental concerns now factor
into policy decisions on the extraction and production of energy and mineral
resources, as well as the disposal of their waste products. A key environmental
issue is the storage of radioactive products from the nuclear arms program of the
Cold War, spent fuel rods from nuclear power plants, and high-level radioactive
wastes from medicine and other applications. Continued research on the level of
seismic and volcanic activity and the stability of the water table will be needed to
ensure the isolation of long-lived radioactive waste in designated underground
repositories such as Yucca Mountain. Materials studies, including at the
microscopic scale, have played an important role in revealing the potential for
containment within or leakage through both the engineered barriers and the
natural media of prospective waste disposal sites.
Mining, milling, and in situ leaching also produce wastes that are toxic to
living organisms. Hardrock mining of metalliferous deposits can release metals
and chemicals such as cyanide to surface and groundwater and to aquatic
ecosystems. Moreover, mining activities directly affect terrestrial ecosystems
because they destroy habitat and alter migration patterns by creating barriers and
fragmenting animal territories. Geochemical, hydrological, mineralogical, and
microbiological research and monitoring will be key to mitigating these adverse
effects. In dealing with these and other challenging problems of the near-surface
environment, basic research is needed to achieve an understanding that reaches
from the atomic scale, at which the detailed fluidflow patterns and the distribution
of contaminants between fluids and solids are determined, to the scale of major
geological features and hydrologic systems, which govern the regional
containment and dispersal of contaminants.
On an even larger scale, human activities are now capable of causing
substantial, if unintended, global environmental change. Anthropogenic
contributions to rising atmospheric CO 2 and other greenhouse gas concentrations
and their potential impact on future climate are issues of global economic and
political significance. Earth science is playing a significant role in understanding
the global carbon budget and key aspects of greenhouse forcing, not only in the
present, but at longer time scales, which are accessible only through the
geological record. Information on paleoenvironments, which is extensive but
relatively unexploited, can be used to identify forcing factors that have controlled
climate in the past, their variation over time, and the causes of rapid transitions in
the climate state. In particular, geochemical, isotopic, and paleontologic analyses
of marine sediments and fossils can be
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