Chapter 4. New Research Challenges For The USGCRP

For the past decade, much of the research supported by the USGCRP has focused on the causes and rates of climate change, with an emphasis on understanding what is occurring at the global scale. This research has made valuable contributions to understanding of the Earth’s climate system and was central to the development of one of the most important findings in the 1995 international scientific assessment by the Intergovernmental Panel on Climate Change, that "the balance of evidence suggests that there is a discernible human influence on global climate."

As the USGCRP prepares to enter its second decade, it is essential that the program continue to deepen and extend scientific understanding by maintaining a very strong research base. At the same time, the program must actively build links to applications of research that can enable society to benefit from the understanding and capabilities that are being developed.

In setting out the challenges for the USGCRP over the next decade, there are a number of opportunities to enhance the role of global change research in providing insights that can be used to benefit society in ways that will promote sustainable development. Some of the key research challenges for the next decade include enhancing efforts to develop:

Key Research Challenges for the Next Decade

  • Regional-scale estimates of the timing and magnitude of global change

  • Regional analyses of the environmental and socio-economic consequences of global change, in the context of other stresses

  • Integrated assessments of the implications for society and the environment of global change

Regional-Scale Estimates

The Earth system is governed by fundamental physical laws that determine its large-scale characteristics. For this reason, and based on understanding gained from observations of past changes in the system, we are becoming better able to predict the large, global-scale behavior of the Earth system.

The primary computer models of global climate, called general circulation models (GCMs), predict a variety of climatic variables, such as temperature, precipitation, winds, snow accumulation, and soil moisture, on spatial scales of several hundred kilometers -- that is, with areas the size of Colorado represented by a single point. While the GCMs provide useful coarse-scale predictions at the sub- continental level, predictions at the regional scale are considered unreliable.

An important USGCRP priority is to improve capabilities for refining large-scale estimates of climate and the global environment and providing the needed finer scale estimates. To be of greatest use for work on the ecological, economic, and social consequences of climate change and to make the results more usable for application studies, models must be strengthened to the point where they can simulate accurately primary processes governing the Earth system on scales of tens of kilometers, rather than hundreds of kilometers. Thus, as the basis for subsequent studies of the consequences of global change, capabilities must be developed to represent such features as changes in the lengths of the seasons, the pattern of changes from mountain to coastal regions, and the evolution of changes from decade to decade.

A range of approaches needs to be considered in order to provide the needed regionally resolved results. Together, these "downscaling" techniques need to be used to improve estimates of changes in drought and flood occurrence, in hurricanes and winter storms, and in extreme highs and lows of temperature -- each focused on changes in particular parts of the country.

Currently there are both theoretical and practical challenges to developing such "regionally resolved" estimates of global climate change. The theoretical challenges to the downscaling involve a range of issues, including how to deal with cloud physics and how to represent the effects of highly variable topography on climate. The practical challenges are focused on the need for enhanced computer power and full utilization of computer resources that are available.

Regional Analyses of Consequences

Policymakers, resource managers, and the public need to know what the consequences of global change will be for their regions, and understand the environmental and socio-economic significance of these consequences:

A key priority is to improve understanding of the potential connections between climate change and the frequency and magnitude of extreme weather events and other disturbances. Some of the regionally specific questions for the United States include:

Disturbances such as fire, drought, floods, and strong winds can, in turn, affect the structure and function of the land and water ecosystems on which society depends. These changes, brought about also by the wide range of other local and regional stresses, will affect the products and services that support economic systems and can lead to changes in plant productivity, nutrient cycles, and species composition.

Scientists do not yet have the capacity to predict these changes with confidence. To do so will require the study of complex interactions among ecological processes through long-term monitoring activities, large-scale field experiments and manipulations, and intensified analysis and simulation modeling efforts.

One of the great new challenges will be to understand how the population dynamics of plants, animals, and microbes are linked to biogeochemical processes. This understanding is needed in order to forecast how climate change will affect the extent and distribution of the Earth’s vegetative cover and its associated animal and microbial species.

Another major new challenge will be to consider the regional consequences of global change in the context of other regional pressures on ecosystems. Each region has its own set of pressures that will act with global change to affect its ecosystems. In the northeastern United States, for example, climate change must be considered along with tropospheric ozone and urban expansion as shapers of ecosystems. Both ozone and urban expansion are also pressures on the ecosystems of southern California, but so too are a suite of pressures related to water use, such as water diversion and salinization of irrigated croplands.

Information on these regional impacts of global-scale change will be essential to policymakers and planners. An enhanced USGCRP research effort on these consequence areas is vital for providing the needed information.

Assessing the Consequences of Global Change

"...stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. Such a level should be achieved within a time frame sufficient to allow ecosystems to adapt naturally to climate change, to ensure that food production is not threatened, and to enable economic development to proceed in a sustainable manner." 

- Ultimate Objective of the UN Framework Convention on Climate Change (Article 2)

The nations of the world have set as a long-term goal the stabilization of atmospheric concentrations of greenhouse gases (GHGs) at a level that will avoid "dangerous anthropogenic interference in the climate system." But what is that level? The judgment of what may be "dangerous" is not a scientific one, as it involves political and ethical value judgments. However, to make this judgement, research must provide policymakers with an understanding of the consequences of different atmospheric concentrations of GHGs for natural ecosystems, food production, and sustainable economic development.

Intensified emphasis on consequences research is needed to build on current knowledge and to improve understanding of the potential impacts of different magnitudes and rates of climate change on, for example, forests, water resources, food and fiber, human infrastructure, human health, and biodiversity:

  • Forests:  Will changes in climate outpace the speed at which forest species grow, reproduce, and reestablish themselves? What fraction of the existing forested areas of the world will undergo major changes in vegetation? How will changes in climate affect the viability of forestry activities, for example in the Southeast or the Pacific Northwest of the United States? Can strategies be developed to assist the migration of individual and perhaps even groups of species?

  • Water Resources:  How will changes in temperature and precipitation, along with potentially non-linear changes in evapotranspiration and soil moisture, affect runoff? How might changes in the seasonal distribution of river flow and water supply affect agriculture and hydroelectric power? Which regions of the United States are most vulnerable to water supply and water quality problems, and what prospective adaptation measures can help reduce the vulnerability of these regions to shortages?

  • Food and Fiber:  Taking into account the beneficial effects of carbon dioxide fertilization, changes in agricultural pests, and possible effects of changing climatic variability, how will food and fiber production be affected in different regions and globally? Where are the optimal regions for growing different crops likely to shift, and how will this affect the farming communities and industries that are currently producing these crops? Internationally, where are the greatest risks of hunger and famine? What information, technologies, and other resources can be provided to assist farmers in adapting to potential changes?

  • Human Infrastructure:  Climate change and rises in sea level clearly will increase the vulnerability of some coastal populations to flooding and erosional land loss. How will changes in the coastal margins affect commercial fisheries production? What are the threats to different coastal regions in the United States and internationally? What strategies can be developed to cope with changes in sea level? How vulnerable is the U.S. financial and insurance system to potential increased losses in coastal areas from changes in the severity and frequency of floods and storms?

  • Human Health:  Climate change has been projected to have wide-ranging impacts on human health. What is the potential public health risk from the interaction of increasingly intense and long heat waves with existing air-quality problems in major urban areas? Are there colder regions in which temperature increases could result in fewer cold-related deaths. What is the relative magnitude of these effects? What is the potential in the United States for increases in the transmission of vector-borne infectious diseases (e.g., malaria, dengue, yellow fever, and some viral encephalitis) resulting from extensions of the geographical range and season for vector organisms such as rodents and insects?

  • Biodiversity and Ecosystem Dynamics:  Vital ecological functions and processes ultimately depend on a diversity of organisms interacting in an ecosystem. Biodiversity found in natural ecosystems also is the source of new chemicals, products, pharmaceuticals, and genes useful for improving agricultural and forestry species. Will changes in climate cause displacement or extinction of species? Will these changes be localized or worldwide? Can species redistribute themselves fast enough to accommodate climate change? Will changes in species composition lead to alterations in ecosystem structure and function?

As future climate extends beyond the boundaries of empirical knowledge from the documented impacts of climate variation in the past, surprises and unanticipated changes will become more likely. Research on the potential consequences of different atmospheric concentrations of greenhouse gases can assist in identifying and preparing for such events.

Integrated Assessment

Changes in the global environment are the subject of wide-ranging debates, intense international negotiations, and policy decisions that have the potential to reach into many aspects of society. Perhaps most far-reaching in their potential implications are the negotiations under the Framework Convention on Climate Change (FCCC).

In general, integrated assessments of global change should be based on the best possible understanding of:

For example, there is a pressing need to support the FCCC negotiations with careful analyses that focus on predictions of causes and effects of climate change through efforts that bring together the physical and biological sciences, economics, and the social sciences.

Thus, in the analysis of climate change, forecasts of greenhouse gases and atmospheric aerosols, which are integral to climate analyses, must consider the forces of population, economic growth, and technology that drive and control emissions. In turn, assessments of possible ecological and socio-economic impacts, and the analyses of alternative strategies for adaptation and mitigation, need to be based on careful climate science that takes into account its own uncertainties.

This challenge of integrated assessment of climate change is beginning to be approached through a coupled-model framework. The models vary in their approach, ranging from those that emphasize detail on the physical and biogeochemical aspects to those that emphasize detail on the behavioral and economic aspects. Integrated assessment models for the analysis of climate change often include an economic model for analyses of emissions of greenhouse gases and aerosol precursors, atmospheric chemistry and general circulation models, and models of natural and managed ecosystems for analyses of the consequences of climate change. At present, models describing complex non-market societal decisions are generally not included. The existing integrated assessment models all run at the global scale, but also are regionally resolved.

Integrated assessment models can be used now to provide indications of many important relationships, including, for example, the significance of technology development in moving toward a more sustainable use of environmental resources, and the combined importance of population growth and energy demand as driving forces leading to global environmental change.

While including many factors of importance, these models are limited by uncertainties in the predicted impacts of global change on unmanaged ecosystems and their consequences, and by the inability to forecast technological changes and responses to policies. As a result, these models cannot yet be used in comprehensive cost- benefit or risk assessment analyses.

The optimum design of integrated assessment models would permit them to address both policy issues and some important questions in global change science. Some of the policy questions being addressed with integrated assessment models include:

Over the next 10 years, research needs to be enhanced so that these evaluation frameworks can be used to improve the texture and richness of the integrated assessments that are being carried out.

The Need for Communication

As the USGCRP addresses these new research challenges, it will generate scientific knowledge needed to develop a sustainable future for our nation and the world. Rigorous scientific research will provide an indispensable contribution to society in meeting the challenge of sustainable development.

Conducting research is of vital importance to society, but it is not sufficient by itself. Scientists must also communicate clearly and responsibly with the public. Communications, often in the form of consensus assessments of what is known and uncertain, must convey scientists’ best understanding of how the Earth’s life support system works, how its behavior affects human activities, and how the Earth system can be affected by human activities.

The communication must also be a dialogue, in which the presentation of scientific information is appropriate to the knowledge and concerns of the recipients, and in which those expressed concerns in turn feed back into the research enterprise, by helping to clarify the critical societal needs that research must help to address.

Epilogue: The Fundamental Rationale

Almost a decade ago, the first edition of Our Changing Planet  ended with the following insight:

"In the coming decades, global change may well represent the most significant societal, environmental, and economic challenges facing this nation and the world. The national goal of developing a predictive understanding of global change is, in its truest sense, science in the service of mankind." 

The fundamental rationale for the USGCRP articulated in 1989 is the same now as it was then.

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