The Role of Adaptation in the U.S.

Climate Change Adaptation Cover  

Coping with Global Climate Change: The Role of Adaptation in the United States

Prepared for the Pew Center on Global Climate Change
June 2004

By:
William Easterling of Pennsylvania State University
Brian Hurd of New Mexico State University
Joel Smith of Stratus Consulting Inc.


Press Release

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Foreword

 

Eileen Claussen, President, Pew Center on Global Climate Change

Throughout the next century and beyond, global climate change will have significant effects on both important economic sectors and natural resources across the United States.   Global temperatures are projected to increase 2.5-10.4oF by 2100, and at least some of this warming is now unavoidable.   Although the natural streams, wetlands, and biodiversity of the United States have a limited capacity to adapt to a changing climate, those systems that are managed by humans, such as agriculture, water resources, and coastal development can be handled in ways to reduce the severity of adverse impacts. 

Adaptation and Global Climate Change discusses how the United States might cope with anticipated climate change impacts in the coming decades.   This report provides a review of the role of adaptation in addressing climate change, the options available for increasing our ability to adapt, and the extent to which adaptation can reduce the consequences of climate change to the U.S. economy and natural resources.  Report authors Bill Easterling, Brian Hurd, and Joel Smith find:

  • Adaptation is an important complement to greenhouse gas mitigation policies. Reducing greenhouse gas emissions is the only effective mechanism for preventing adverse impacts of climate change.  However, given that additional future climate change is now inevitable regardless of mitigation efforts, adaptation is an essential strategy for reducing the severity and cost of climate change impacts.
     
  • Adapting to climate change will not be a smooth or cost-free endeavor.  Although the United States has diverse options and resources for adapting to the adverse effects of climate change, changes will be made in an atmosphere of uncertainty.  Substantial investments and adjustments will need to be made even with imperfect information or foresight, and successful adaptation will become even more challenging with more rapid rates or greater degrees of warming.
     
  • Managed systems will fare better than natural systems and some regions will face greater obstacles than others. Even if there are some successes in adapting to climate change at the national level, there will still be regional and sectoral losers.  In particular, there is limited ability for humans to improve the adaptive capacity of natural ecosystems, which are not as easily managed and which face degradation from multiple stresses.
     
  • Proactive approaches to adaptation are more likely to avoid or reduce damages than reactive responses.   Anticipatory planning among government institutions and important economic sectors will enhance the resilience to the effects of climate change.  Government at all levels should consider the implications of climate change when making investments in long-lived infrastructure.

The authors and the Pew Center gratefully acknowledge the input of Drs. Gary Yohe and Paul Kirshen on this report.

Executive Summary

 

Climate change resulting from increased greenhouse gas concentrations has the potential to harm societies and ecosystems. In particular, agriculture, forestry, water resources, human health, coastal settlements, and natural ecosystems will need to adapt to a changing climate or face diminished functions. Reductions in emissions of greenhouse gases and their concentration in the atmosphere will tend to reduce the degree and likelihood that significantly adverse conditions will result. Consideration of actions—e.g., mitigation policy—that can reduce this likelihood is reasonable and prudent, and has generally been the primary focus of public attention and policy efforts on climate change. However, recognition is increasing that the combination of continued increases in emissions and the inertia of the climate system means that some degree of climate change is inevitable. Even if extreme measures could be instantly taken to curtail global emissions, the momentum of the earth’s climate is such that warming cannot be completely avoided. Although essential for limiting the extent, and indeed the probability, of rapid and severe climate change, mitigation is not, and this paper argues, should not be, the only protective action in society’s arsenal of responses.

Adaptation actions and strategies present a complementary approach to mitigation. While mitigation can be viewed as reducing the likelihood of adverse conditions, adaptation can be viewed as reducing the severity of many impacts if adverse conditions prevail. That is, adaptation reduces the level of damages that might have otherwise occurred. However, adaptation is a risk-management strategy that is not free of cost nor foolproof, and the worthiness of any specific actions must therefore carefully weigh the expected value of the avoided damages against the real costs of implementing the adaptation strategy.

Adaptation to environmental change is a fundamental human trait and is not a new concept. Throughout the ages, human societies have shown a strong capacity for adapting to different climates and environmental changes, although not always successfully. As evidenced by the widespread and climatically diverse location of human settlements throughout the world, humans have learned how to thrive in a wide variety of climate regimes, ranging from cold to hot and from humid to dry. The resilience and flexibility exhibited in the patterns of human settlements evidence an inherent desire and some measure of capacity to adapt.

For human systems, the success of adaptation depends critically on the availability of necessary resources, not only financial and natural resources, but also knowledge, technical capability, and institutional resources. The types and levels of required resources, in turn, depend fundamentally on the nature and abruptness of the actual or anticipated environmental change and the range of considered responses.

The processes of adaptation to climate change in both human and natural systems are highly complex and dynamic, often entailing many feedbacks and dependencies on existing local and temporal conditions. The uncertainties introduced by the complexity, scale and limited experience with respect to anthropogenic climate change explains the limited level of applied research conducted thus far on adaptation, the reliance on mechanistic assumptions, and widespread use of scenarios and historical analogues. In addition, many social, economic, technological and environmental trends will critically shape the future ability of societal systems to adapt to climate change. While such factors as increased population and wealth will likely increase the potential level of material assets that are exposed to the risks of climate change, greater wealth and improved technology also extend the resources and perhaps the capabilities to adapt to climate change. These trends must be taken into account when evaluating the nature and scale of future adaptive responses and the likelihood that they will succeed.

The implications of climate change are more dire for natural systems, because it will be difficult for many species to change behavior or migrate in response to climate change. While biological systems might accommodate minor (or slowly occurring) perturbations in a smooth continuous fashion, even minor changes in climate may be disruptive for many ecosystems and individual species. In addition, many of the world’s species are currently stressed by a variety of factors including urban development, pollution, invasive species, and fractured (or isolated) habitats. Such conditions, coupled with the relatively rapid rate of anticipated climate change, are likely to challenge many species’ resiliency and chances for successful adaptation.

Key insights and findings on adaptation and its potential for success are summarized below:

  1. Adaptation and mitigation are necessary and complementary for a comprehensive and coordinated strategy that addresses the problem of global climate change. By lessening the severity of possible damages, adaptation is a key defensive measure. Adaptation is particularly important given the mounting evidence that some degree of climate change is inevitable. Recognizing a role for adaptation does not, however, diminish or detract from the importance of mitigation in reducing the rate and likelihood of significant climate change.
     
  2. The literature indicates that U.S. society can on the whole adapt with either net gains or some costs if warming occurs at the lower end of the projected range of magnitude, assuming no change in climate variability and generally making optimistic assumptions about adaptation. However, with a much larger magnitude of warming, even making relatively optimistic assumptions about adaptation, many sectors would experience net losses and higher costs. The thresholds in terms of magnitudes or rates of change (including possible non-linear responses) in climate that will pose difficulty for adaptation are uncertain. In addition, it is uncertain how much of an increase in frequency, intensity, or persistence of extreme weather events the United States can tolerate.
     
  3. To say that society as a whole “can adapt“ does not mean that regions and peoples will not suffer losses. For example, while the agricultural sector as a whole may successfully adapt, some regions may gain and others may lose. Agriculture in many northern regions is expected to adapt to climate change by taking advantage of changing climatic conditions to expand production, but agriculture in many southern regions is expected to contract with warmer, drier temperatures. Individual farmers not benefiting from adaptation may lose their livelihood.  In addition, other individuals or populations in these and other regions can be at risk, because they could be adversely affected by climate change and lack the capacity to adapt.  This is particularly true of relatively low-income individuals and groups whose livelihoods are depending on resources at risk by climate change.
     
  4. Adaptation is not likely to be a smooth process or free of costs. While studies and history show that society can on the whole adapt to a moderate amount of warming, it is reasonable to expect that mistakes will be made and costs will be incurred along the way. People are neither so foolish as to continue doing what they have always done in the face of climate change, nor so omniscient as to perfectly understand what will need to be done and to carry it out most efficiently. In reality, we are more likely to muddle through, taking adaptive actions as necessary, but often not doing what may be needed for optimal or ideal adaptation. Additionally, adaptation is an on-going process rather than a one-shot instantaneous occurrence.  Compounding society’s shortcomings, a more rapid, variable, or generally unpredictable climate change would add further challenges to adaptation.
     
  5. Effects on ecosystems, and on species diversity in particular, are expected to be negative at all but perhaps the lowest magnitudes of climate change because of the limited ability of natural systems to adapt. Although biological systems have an inherent capacity to adapt to changes in environmental conditions, given the rapid rate of projected climate change, adaptive capacity is likely to be exceeded for many species. Furthermore, the ability of ecosystems to adapt to climate change is severely limited by the effects of urbanization, barriers to migration paths, and fragmentation of ecosystems, all of which have already critically stressed ecosystems independent of climate change itself.
     
  6. Institutional design and structure can heighten or diminish society’s exposure to climate risks. Long-standing institutions, such as disaster relief payments and insurance programs, affect adaptive capacity. Coastal zoning, land-use planning, and building codes are all examples of institutions that can contribute to (or detract from) the capacity to withstand climate changes in efficient and effective ways.
     
  7. Proactive adaptation can reduce U.S. vulnerability to climate change. Proactive adaptation can improve capacities to cope with climate change by taking climate change into account in long-term decision-making, removing disincentives for changing behavior in response to climate change (such as removing subsidies for maladaptive activities), and introducing incentives to modify behavior in response to climate change (such as the use of market-based mechanisms to promote adaptive responses). Furthermore, improving and strengthening human capital through education, outreach, and extension services improves decision-making capacity at every level and increases the collective capacity to adapt.

Conclusions

 

As the climate-change research and policy communities fully confront the challenges of understanding and managing adaptation to climate change, the issues framed in this report provide important insight concerning the information needed to make appropriate policy choices regarding adaptation. The following conclusions provide initial guidance to those communities:

  1. Adaptation and mitigation are necessary and complementary for a comprehensive and coordinated strategy that addresses the problem of global climate change. By lessening the severity of possible damages, adaptation is a key defensive measure. Adaptation is particularly important given the mounting evidence that some degree of climate change is inevitable. Recognizing a role for adaptation does not, however, diminish or detract from the importance of mitigation in reducing the rate and likelihood of significant climate change.
     
  2. The literature indicates that U.S. society can on the whole adapt with either net gains or some costs if warming occurs at the lower end of the projected range of magnitude, assuming no change in climate variability and generally making optimistic assumptions about adaptation. However, with a much larger magnitude of warming, even making relatively optimistic assumptions about adaptation, many sectors would experience net losses and higher costs. The thresholds in terms of magnitudes or rates of change (including possible non-linear responses) in climate that will pose difficulty for adaptation are uncertain. In addition, it is uncertain how much of an increase in frequency, intensity, or persistence of extreme weather events the United States can tolerate.
     
  3. To say that society as a whole “can adapt“ does not mean that regions and peoples will not suffer losses. For example, while the agricultural sector as a whole may successfully adapt, some regions may gain and others may lose. Agriculture in many northern regions is expected to adapt to climate change by taking advantage of changing climatic conditions to expand production, but agriculture in many southern regions is expected to contract with warmer, drier temperatures. Individual farmers not benefiting from adaptation may lose their livelihood. In addition, other individuals or populations in these and other regions can be at risk, because they could be adversely affected by climate change and lack the capacity to adapt.  This is particularly true of relatively low-income individuals and groups whose livelihoods are depending on resources at risk by climate change.
     
  4. Adaptation is not likely to be a smooth process or free of costs. While studies and history show that society can on the whole adapt to a moderate amount of warming, it is reasonable to expect that mistakes will be made and costs will be incurred along the way. People are neither so foolish as to continue doing what they have always done in the face of climate change, nor so omniscient as to perfectly understand what will need to be done and to carry it out most efficiently. In reality, we are more likely to muddle through, taking adaptive actions as necessary, but often not doing what may be needed for optimal or ideal adaptation. Additionally, adaptation is an on-going process rather than a one-shot instantaneous occurrence.  Compounding society’s shortcomings, a more rapid, variable, or generally unpredictable climate change would add further challenges to adaptation.
     
  5. Effects on ecosystems, and on species diversity in particular, are expected to be negative at all but perhaps the lowest magnitudes of climate change because of the limited ability of natural systems to adapt. Although biological systems have an inherent capacity to adapt to changes in environmental conditions, given the rapid rate of projected climate change, adaptive capacity is likely to be exceeded for many species. Furthermore, the ability of ecosystems to adapt to climate change is severely limited by the effects of urbanization, barriers to migration paths, and fragmentation of ecosystems, all of which have already critically stressed ecosystems independent of climate change itself.
     
  6. Institutional design and structure can heighten or diminish society’s exposure to climate risks. Long-standing institutions, such as disaster relief payments and insurance programs, affect adaptive capacity. Coastal zoning, land-use planning, and building codes are all examples of institutions that can contribute to (or detract from) the capacity to withstand climate changes in efficient and effective ways. 
     
  7. Proactive adaptation can reduce U.S. vulnerability to climate change. Proactive adaptation can improve capacities to cope with climate change by taking climate change into account in long-term decision-making, removing disincentives for changing behavior in response to climate change (such as removing subsidies for maladaptive activities), and introducing incentives to modify behavior in response to climate change (such as the use of market-based mechanisms to promote adaptive responses). Furthermore, improving and strengthening human capital through education, outreach, and extension services improves decision-making capacity at every level and increases the collective capacity to adapt.

About the Authors

 

Dr. William E. Easterling
Dr. William E. Easterling is the Director of the Institutes of Environment and a professor of geography and agronomy at Pennsylvania State University.   Prior to joining the faculty at Penn State, Dr. Easterling held appointments in the Department of Agricultural Meteorology at the University of Nebraska (1991-1997), Resources for the Future, Inc. in Washington, DC (1987-1991), and the Illinois State Water Survey at the University of Illinois (1984-1987).  He received his doctorate in geography from the University of North Carolina at Chapel Hill.  Dr. Easterling's research concerns the interactions of human activities with their climatic and biotic environment, particularly the potential effects of climate changes from greenhouse warming on agroecosystem productivity and adaptation in both developed and developing countries. He also serves or has served on numerous national and international scientific advisory committees and assessment projects, including those of the National Research Council, the National Science Foundation, the National Aeronautics and Space Administration, the National Oceanic and Atmospheric Administration, and the U. S. Department of Energy. He served as the Acting Director of the Department of Energy's National Institute for Global Environmental Change (1996-1998), and he was a convening lead author for the Third Assessment Report of the United Nations/World Meteorological Organization's Intergovernmental Panel on Climate Change. In the winter of 2003, he co-chaired newly elected Pennsylvania Governor Ed Rendell's Transition Committee on Conservation and Natural Resources and was elected to serve as the Chair of the Penn State University Research Council for 2003-2004.

Brian H. Hurd, New Mexico State University
Brian H. Hurd is an Assistant Professor in the Department of Agricultural Economics and Agricultural Business at New Mexico State University. Dr. Hurd earned his PhD and MS degrees in Agricultural Economics from the University of California, Davis, and holds a BA from the University of Colorado, Boulder.

Dr. Hurd is the author of numerous articles, book chapters and conference presentations on natural and environmental resource economics, water resource economics, and climate change vulnerability and adaptation. He is a delegate to the Universities Council on Water Resources (UCOWR), and is a member of the American Agricultural Economics Association, the Association of Environmental and Resource Economists, the American Water Resources Association, and the Western Agricultural Economics Association. 

Joel B. Smith, Stratus Consulting Inc.
Joel B. Smith is the Vice President of Stratus Consulting Inc. Mr. Smith received a BA from Williams College, and received an MPP from the University of Michigan.

Mr. Smith has examined climate change impacts and adaptation issues for the U.S. Country Studies Program, the U.S. Environmental Protection Agency, the U.S. Department of Energy, the U.S. Agency for International Development, the Office of Technology Assessment, the Electric Power Research Institute, the World Bank, the Global Environment Facility, the United Nations Environment Programme, and the International Institute for Applied Systems Analysis.

Before joining Stratus Consulting, Mr. Smith was the deputy director of the U.S. EPA's Climate Change Division. He was a coeditor of EPA's Report to Congress: The Potential Effects of Global Climate Change on the United States, published in 1989; As Climate Changes: International Impacts and Implications, published by Cambridge University Press in 1995; Adaptation to Climate Change: Assessments and Issues, published by Springer-Verlag in 1996; and Climate Change, Adaptive Capacity and Development published by Imperial College Press in 2003. Mr. Smith worked for the EPA from 1984 to 1992. Besides working on climate change issues, he also served as an analyst examining oceans and water regulations, and was a special assistant to the Assistant Administrator for the Office of Policy, Planning and Evaluation.