Strategic Research Questions 9.1. What are the magnitudes, interrelationships, and significance of the primary human drivers of, and their potential impact on, global environmental change? 9.2. What are the current and potential future impacts of global environmental variability and change on human welfare, what factors influence the capacity of human societies to respond to change, and how can resilience be increased and vulnerability reduced? 9.3.  How can the methods and capabilities for societal decisionmaking under conditions of complexity and uncertainty about global environmental variability and change be enhanced? 9.4. What are the potential human health effects of global environmental change, and what climate, socioeconomic, and environmental information is needed to assess the cumulative risk to health from these effects? See Strategic Plan for the U.S. Climate Change Science Program, Chapter 9, for detailed discussion of these research questions.

Human activities play an important part in virtually all natural systems and are forces for change in the environment at local, regional, and even global scales. Social, economic, and cultural systems are changing in a world that is more populated, urban, and interconnected than ever. Such large-scale changes increase the resilience of some groups while increasing the vulnerability of others. A better integrated understanding of the complex interactions between human societies and the Earth system is needed if we are to identify vulnerable systems and pursue options that take advantage of opportunities to enhance resilience.

Research on human contributions and responses 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. Human drivers of global environmental change include consumption of energy and natural resources, technological and economic choices, culture, and institutions. The effects of these drivers are seen in population growth and movement, changes in consumption, de- or reforestation, land-use change, and toleration or regulation of pollution.

Figure 8.1. 
Urban Population Density
of North America
 

Global environmental variability and change must be analyzed in the context of other natural and social system stresses, such as land-use and land-cover change, population changes and migrations, and global economic restructuring. There has been significant progress in analyzing and modeling regional vulnerabilities and possibilities for adaptation, including in the context of multiple stresses. Progress has been made in understanding how society adapts to seasonal climate variability and, by extension, how it may adapt to potential longer term climate change

It is well-established that human health is linked to environmental conditions, and that changes in the natural environment may have subtle, or dramatic, effects on health. Timely knowledge of these effects may support public health systems in devising and implementing strategies to compensate or respond to these effects. 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 particles and aeroallergens, ultraviolet (UV) radiation, vector- and water-borne diseases, and heat-related illnesses.

Decisionmaking is challenged by uncertainties including risks of irreversible and/or nonlinear changes that may be met with insufficient or excessive responses whose consequences may cascade across generations. The difficulties associated with uncertainty have become increasingly salient given the interest of policymakers in addressing global environmental change.

The NRC 2001 report, Climate Change Science: An Analysis of Some Key Questions, 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.”