Strategic Plan for the
Climate Change
Science Program
Review draft, November 2002

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Chapter 11
Human Contributions and Responses to Environmental Change

Human activities play an important part in virtually all "natural" systems and are changing the environment at local, regional, and even global scales. Social, economic, and cultural systems also are changing in a world that is more populated, urban, and interconnected, increasing the resilience of some groups while increasing the vulnerability of others. A more integrated understanding of the complex interactions of human societies and the Earth system is essential to identify vulnerable systems and pursue options to take advantage of opportunities and enhance resilience.

The need for research on human contributions and responses -- sometimes referred to as the "human dimensions" of global change -- motivates research questions throughout this plan. Human dimensions research includes studies of potential technological, social, economic, and cultural drivers of global change, and how these and other aspects of human systems may affect adaptation and the consequences of change for society. Much of this research is "cross-cutting" -- integral to explorations of causes and impacts of changes in atmospheric composition, climate, the water cycle, the carbon cycle, ecosystems, land use and land cover, and other global changes. Research on human contributions and responses also is an area of study in its own right. Common forcing scenarios must be developed that integrate information from different research elements. The interacting impacts of multiple environmental stressors on human activities must be examined. New hypotheses, methods, and models must be developed and tested.

A series of national and international reports has identified a broad research agenda addressing human contributions and responses (including adaptation) to global change. The National Research Council (NRC) has issued several reports that identify key research issues, most recently including Global Environmental Change: Research Pathways for the Next Decade (NRC, 1999a), which includes a chapter on "Human Dimensions of Global Environmental Change," and Under the Weather: Climate, Ecosystems, and Infectious Disease (NRC, 2001c). The NRC report Climate Change Science: An Analysis of Some Key Questions  (NRC, 2001a) concluded that, "In order to address the consequences of climate change and better serve the Nation's decisionmakers, the research enterprise dealing with environmental change and environment-society interactions must be enhanced." This enterprise should include (among other elements), "support of interdisciplinary research that couples physical, chemical, biological, and human systems." This chapter draws from these reports and from priority areas identified by the research community through federal research programs.

Two overarching questions for research on the human contributions and responses to global change are:

These questions are addressed through research focused on the following areas:

In all of these areas of research, there is a particularly strong need for the integration of social, economic, and health data with environmental data. This will require data from physical, biological, social, and health disciplines on compatible temporal and spatial scales, to support the integration of the data for research and to support decisionmaking.

The influence of human drivers of global environmental change may be greater, yet be modeled with more uncertainty, than the influence of some factors studied in the natural sciences. For example, as difficult as it might be to predict the response of tropical forests to increasing levels of carbon dioxide (CO₂), it is probably more difficult, yet might be more important, to project the rates and patterns of global deforestation and the potential effectiveness of policies to control it.

The subject of potential human drivers is very broad. Research has been conducted for many years in many fields and for many reasons. However, the level of understanding achieved to date is quite uneven. Researchers who need to model human actions in order to project future conditions and consequences often find the foundation for quantitative models lacking.

What are the key processes and trends associated with population growth and demographic change, technological change, and trade and global economic activity, and how can improved understanding of these issues be used to improve scenarios and projections of global change?

Key needs have been identified, including:

Users of the results of this research will have an improved understanding of the variables affected by human actions. For example, the preparation of scenarios will be strengthened by an improved understanding of the interdependence among economic growth, population growth, energy consumption in different sectors (e.g., electricity, transportation), pollutant emissions, and migration. Research will provide a basis for improving the development and evaluation of those scenarios.

Research has shown that the extent to which global environmental change can affect societies depends as much on the social systems that lead to vulnerability as on the biophysical systems that cause environmental change. This is the case, for example, in understanding how climate variability in the past has affected societies. According to the NRC Pathways report (NRC, 1999a), "a major conceptual advance occurred in moving from impact assessments based on climate model scenarios to analyses based on an understanding of vulnerability. For example, rapid increases in water demand have increased drought vulnerability, and the spread of urban settlements into coastal and flood-prone regions has increased vulnerability to sea level rise and severe storms." Moreover, the capacity of society to prepare for climate impacts will be influenced in part by the capacity of individuals and institutions to respond to improved scientific information.

Associated research needs include empirical studies, field campaigns, and model-based simulation studies of the influence of social and economic factors on vulnerability and adaptive capacity in households, organizations, and communities; analyses of the consequences of rapid climate changes in the past and the ability of hazard and resource management institutions to respond to surprising shifts in climate and to seasonal forecasts; and studies analyzing the factors that affect adaptive capacity in the context of multiple social and natural system stresses (climate change, land use change, population change and movements, sea level rise, and changes in political institutions).

Research on these questions can be expected to improve analytical methods and models of how climate variability and change, land use change, population change, sea level rise, and other global environmental changes affect decisionmaking in public health, water management, agriculture, transportation infrastructure, urban areas, coastal areas, and other climate-sensitive sectors. Improved communication and dissemination of accurate climate information, including characterization of uncertainty, is being developed that attempts to meet the needs of decisionmakers in these sectors.

Research suggests that the potential social and economic impacts of global climatic variability and change may be very large. Much less research has been devoted to examining how individuals, organizations, and governments can make better decisions to reduce risks and take advantage of opportunities related to global climatic variability and change.

How can methods or approaches be improved:

Associated research needs include research to determine what information is required by individuals, organizations, and governments to make better decisions regarding global environmental variability and change; what individuals, organizations, and governments know (and do not know), including uncertainties, about the state of scientific knowledge regarding global environmental change; and what decision resources would be most useful for different decisionmakers in different positions.

Research on these questions will enable the development of assessments of the kind of knowledge and information needed by different decisionmakers and stakeholders in order to enhance decisionmaking associated with climate change, and will produce decision support resources.

It is well established that human health is inextricably linked to the environment, and that changes in the natural environment may have a subtle, or even dramatic, effect on health. Over the past decade, several research and agenda-setting exercises have called for continued and expanded research and development of research methods in this area. Given the complex interactions among physical, biological, and human systems, this research must be highly interdisciplinary, well integrated, and span the breadth from fundamental research to operations. An interdisciplinary research program to examine the linkages across these sectors is being initiated in 2003. Focusing on global and developing country impacts, it will begin to improve understanding of how human health is affected by simultaneous environmental and economic shifts.

Federally supported research has thus far provided information on a broad range of health effects of global change, including the adverse effects of ozone, atmospheric particulates, ultraviolet (UV) radiation, and heat-related illnesses. Research continues to improve understanding of the impact of climate variability on certain infectious diseases, and researchers are developing tools and information products for anticipating and managing these impacts that capitalize on the enormous protections afforded by wealth and the public health infrastructure. However, many questions remain unanswered.

Research needs include:

A parallel need exists to develop additional appropriate tools and methods for assessing and adapting to potential health outcomes; and for evaluating the impact of research, the effectiveness of Earth science information and products, the methods for communicating that information, and the systematic identification of knowledge gaps and feedback to the research communities.

Products from this area include operational tools, research to support innovative institutional arrangements and processes, and fundamental research results that may be used by decisionmakers. Expected products include:

The study of human contributions and responses to global change has ties to all of the Climate Change Science Program (CCSP) research elements, and in many cases needs to be an integral component of collaborative research within these elements. For example, research to identify options for increasing the resilience of national water systems to climate variability and to long-term socioeconomic and climate trends is linked to Water Cycle research (Chapter 7). Similarly, an evaluation of local- and regional-scale factors that condition impacts of land use and land cover change on economic welfare and human health is equal parts Land Use/Land Cover Change research (Chapter 8) and Human Contributions and Responses research. Research on human disease vectors is linked to the study of Ecosystems (Chapter 10). Comparable examples can be cited for Atmospheric Composition (Chapter 5), Climate Variability and Change (Chapter 6), and the Carbon Cycle (Chapter 9).

Questions from other research elements that are related to Question 1 above include:

Questions from other research elements that are related to Question 2 above include:

Questions from other research elements that are related to Question 3 above include:

Research on Human Contributions and Responses to Environmental Change is linked to the International Human Dimensions Programme and to a variety of other international efforts, including the International Research Institute for Climate Prediction (see Chapter 14).

NRC, 1999a. Committee on Global Change Research, National Research Council, Global Environmental Change: Research Pathways for the Next Decade (Washington, DC: National Academy Press).

NRC, 2001a.  National Research Council, Committee on the Science of Climate Change, Climate Change Science: An Analysis of Some Key Questions (Washington, DC: National Academy Press).

NRC, 2001c.  Committee on Climate, Ecosystems, Infectious Diseases, and Human Health, Board on Atmospheric Sciences and Climate, National Research Council, Under the Weather: Climate, Ecosystems, and Infectious Disease  (Washington, DC: National Academy Press).