Scientists have long worked to understand the environment and humanity 's place in it. The search for this knowledge grows in importance as rapid increases in human populations and economic development intensify the stresses human beings place on the biosphere and ecosystems. People want to be warned of major environmental changes and, if the environment is under threat, want to know how to respond. Fortunately, rapid increases in scientific capability—such as recent advances in computing power and molecular biology and new techniques for sensing biological, physical, and chemical phenomena below, on, and above the Earth's surface—together with the rediscovery that the human-environment relationship is a critical topic for the human sciences, are making it possible for science to provide much of this knowledge. The scientific excitement and challenge of understanding the complex environmental systems humans depend on make the environmental sciences centrally important as humankind attempts a transition to a more sustainable relationship with the Earth and its natural resources.
This report was written in response to a request from the National Science Foundation (NSF) that the National Research Council (NRC), drawing on expertise from across the environmental sciences, offer a judgment regarding the most important environmental research challenges of the next generation—the areas most likely to yield results of major scientific and practical importance if pursued vigorously now. In formulating this judgment, the committee established by the NRC confronted the problem of the unity of the environment—the fact that every aspect of the environment is connected to every other in some way.
Consequently, no branch of environmental science can progress very far without drawing on knowledge from other branches.
The committee sought to identify a small number of grand challenges in the environmental sciences—major scientific tasks that are compelling for both intellectual and practical reasons, that offer potential for major breakthroughs on the basis of recent developments in science and technology, and that are feasible given current capabilities and a serious infusion of resources. After soliciting input as broadly as possible and considering more than 200 nominations from the scientific community, the committee selected the eight grand challenges described below. The committee's selection criteria included probability of significant scientific and practical payoff, large scope, relevance to important environmental issues, feasibility, timeliness, and requirement for multidisciplinary collaboration.
Attaining the needed environmental knowledge for the next generation will depend on the active pursuit of all eight grand challenges. However, the committee was asked to identify an even more focused list of activities to be pursued in the near term by NSF, either alone or in collaboration with other research funders. Therefore, the committee selected four areas, derived from the grand challenges, to recommend for immediate research investment by NSF and others. In addition to the criteria used to choose the eight grand challenges, the committee considered whether the activities are currently underfunded, i.e., stand to benefit from an infusion of financial and human resources; the committee also applied the criteria of scientific importance, urgency, and scope. The committee did not rank-order the grand challenges, as we consider them all to be broadly and deeply important, nor did we rank-order the immediate research investments for the same reason. Both are therefore presented below in alphabetical order.
THE GRAND CHALLENGES
1. Biogeochemical Cycles
The challenge is to further our understanding of the Earth's major biogeochemical cycles, evaluate how they are being perturbed by human activities, and determine how they might better be stabilized. Important research areas include quantifying the sources and sinks of the nutrient elements and gaining a better understanding of the biological, chemical, and physical factors regulating transformations among them; improving understanding of the interactions among the various biogeochemical cycles; assessing anthropogenic perturbations of biogeochemical cycles and their impacts on ecosystem functioning, atmospheric chemistry, and human activities, and developing a scientific basis for societal decisions about managing these cycles; and exploring technical and institutional approaches to managing anthropogenic perturbations.
2. Biological Diversity and Ecosystem Functioning
The challenge is to improve understanding of the factors affecting biological diversity and ecosystem structure and functioning, including the role of human activity. Important research areas include improving tools for rapid assessment of diversity at all scales; producing a quantitative, process-based theory of biological diversity at the largest possible variety of spatial and temporal scales; elucidating the relationship between diversity and ecosystem functioning; and developing and testing techniques for modifying, creating, and managing habitats that can sustain biological diversity, as well as people and their activities.
3. Climate Variability
The challenge is to increase our ability to predict climate variations, from extreme events to decadal time scales; to understand how this variability may change in the future; and to assess realistically the resulting impacts. Important research areas include improving observational capability, extending the record of observations back into the Earth's history, improving diagnostic process studies, developing increasingly comprehensive models, and conducting integrated impact assessments that take human responses and impacts into account.
4. Hydrologic Forecasting
The challenge is to develop an improved understanding of and ability to predict changes in freshwater resources and the environment caused by floods, droughts, sedimentation, and contamination. Important research areas include improving understanding of hydrologic responses to precipitation, surface water generation and transport, environmental stresses on aquatic ecosystems, the relationships between landscape changes and sediment fluxes, and subsurface transport, as well as mapping groundwater recharge and discharge vulnerability.
5. Infectious Disease and the Environment
The challenge is to understand ecological and evolutionary aspects of infectious diseases; develop an understanding of the interactions among pathogens, hosts/receptors, and the environment; and thus make it possible to prevent changes in the infectivity and virulence of organisms that threaten plant, animal, and human health at the population level. Important research areas include examining the effects of environmental changes as selection agents on pathogen virulence and host resistance; exploring the impacts of environmental change on disease etiology, vectors, and toxic organisms; developing new approaches to surveillance and monitoring; and improving theoretical models of host-pathogen ecology.
6. Institutions and Resource Use
The challenge is to understand how human use of natural resources is shaped by institutions such as markets, governments, international treaties, and formal and informal sets of rules that are established to govern resource extraction, waste disposal, and other environmentally important activities. Important research areas include documenting the institutions governing critical lands, resources, and environments; identifying the performance attributes of the full range of institutions governing resources and environments worldwide, from local to global levels; improving understanding of change in resource institutions; and conceptualizing and assessing the effects of institutions for managing global commons.
7. Land-Use Dynamics
The challenge is to develop a systematic understanding of changes in land uses and land covers that are critical to ecosystem functioning and services and human welfare. Important areas for research include developing long-term, regional databases for land uses, land covers, and related social information; developing spatially explicit and multisectoral land-change theory; linking land-change theory to space-based imagery; and developing innovative applications of dynamic spatial simulation techniques.
8. Reinventing the Use of Materials
The challenge is to develop a quantitative understanding of the global budgets and cycles of materials widely used by humanity and of how the life cycles of these materials (their history from the raw-material stage through recycling or disposal) may be modified. Important research areas include developing spatially explicit budgets for selected key materials; developing methods for more complete cycling of technological materials; determining how best to utilize materials that have uniquely useful industrial applications but are potentially hazardous to the environment; developing an understanding of the patterns and driving forces of human consumption of resources; and developing models for possible global scenarios of future industrial development and associated environmental implications.
RECOMMENDED IMMEDIATE RESEARCH INVESTMENTS
The committee recommends that immediate investments be made in four priority research areas related to the grand challenges.
1. Biological Diversity and Ecosystem Functioning
Recommendation: Develop a comprehensive understanding of the relationship between ecosystem structure and functioning and biological diversity. This initiative would include experiments, obser vations, and theory, and should have two interrelated foci: (a) de veloping the scientific knowledge needed to enable the design and management of habitats that can support both human uses and native biota; and (b) developing a detailed understanding of the effects of habitat alteration and loss on biological diversity, espe cially those species and ecosystems whose disappearance would like ly do disproportionate harm to the ability of ecosystems to meet human needs or set in motion the extinction of many other species.
2. Hydrologic Forecasting
Recommendation: Establish the capacity for detailed, comprehensive hydrologic forecasting, including the ecological consequences of changing water regimes, in each of the primary U.S. climatologi cal and hydrologic regions. Important specific research areas include all those described under Grand Challenge 4.
3. Infectious Disease and the Environment
Recommendation: Develop a comprehensive ecological and evolutionary understanding of infectious diseases affecting human, plant, and animal health.
4. Land-Use Dynamics
Recommendation: Develop a spatially explicit understanding of changes in land uses and land covers and their consequences.
The identification of grand challenges in environmental sciences and priorities for immediate research investment is only a prelude. The key then becomes implementation. In the committee's view, several critical implementation issues cut across all of the research areas identified. These issues include such matters as whether to proceed by establishing regional research centers, how best to support interdisciplinary research, and how to make environmental science useful to decision makers and managers and the public.
Recommendation: NSF, together with other agencies as appropriate, should conduct workshops that include research scientists in academia, the relevant agencies, and the private sector, as well as potential users of the research results, to discuss and plan research agendas and address implementation issues.