For more than 50 years, the Earth’s climate has been changing due to increasing greenhouse gas (GHG) emissions from the burning of fossil fuels such as coal and oil, as well as deforestation and other human activities. The warming of the Earth’s atmosphere and waters, loss of land and sea ice, and rising global sea levels are not new phenomena. However, these global changes have been occurring at increasing rates in the last 30 years, particularly in the last decade. Science shows that climate change will continue, and accelerate, in the years ahead, with significant impacts on the health of all our global ecosystems including oceans, forests, freshwater, and even human and urban ecosystems and the resources they contain.

While substantially reducing GHG emissions is essential to avoiding the worst impacts of climate change, mitigation alone is not enough. Even with emission reductions, some warming will still occur. Adaptation planning at the local, state, and national levels can limit the damage caused by climate change, as well as the long-term costs of responding to climate-related impacts that are expected to grow in number and intensity in the decades to come.

Read more about adaptation planning and its importance in the effort to curb global warming below.


Current and Potential Impacts

  • If GHG emissions continue unabated, the continental United States is expected to warm one-third more than global averages, meaning that Americans can expect an increase of 3–7ºC (5.4–12.6ºF), depending on where they live.
  • For Alaska and the Arctic region as a whole, warming projections of 4–11ºC (7.2–19.8ºF) are at least double the mean increase for the world. And the Arctic region is already experiencing an array of impacts including severe winter storm surges and flooding, infrastructure damage and loss, land erosion, species loss, and the displacement of people and communities.
  • In the U.S., scientists expect to see overall increases in precipitation (along with decreases in some areas such as the Southwest), including increases in the intensity of hurricanes and more intense heavy rainfalls.
  • Projected impacts also indicate a decline in snowpack, earlier snow and ice melt in areas including the West and Great Lakes regions, and more land areas affected by drought and wildfires.
  • Sea-level rise will affect the U.S. coastline to varying degrees, with the most severe impacts projected along the Gulf of Mexico and Atlantic coastlines, including potentially significant losses of coastal wetlands.
  • All of these impacts will affect food and water supplies, natural resources, ecosystems and human life and property.


Mitigation is not Enough

    • Carbon dioxide (CO2) and other GHGs can remain in the atmosphere for decades or centuries after they are produced. This means that today’s emissions will affect the climate for years to come, just as the warming we are experiencing now is the result of emissions produced in the past.
    • Because of this time lag, the Earth is committed to some additional warming no matter what happens now to reduce emissions. With worldwide emissions continuing to rise, adaptation efforts are necessary to reduce both the cost and severity of both mitigation and climate change impacts for decades to come.
    • Current projections have underestimated the actual rates of climatic changes and impacts. For instance, sea-level rise has occurred 50% faster than the projected rate, and the area of summer Arctic sea ice has decreased at three times the projected rate.
    • Acting now to limit the potential damage from climate change is often smarter—and costs less in the long run—than acting later. “Proactive adaption” requires assessing the vulnerability of natural and man-made systems, as well as the costs and benefits of action versus inaction, and planning alternatives accordingly. From the methods for building or repairing bridges, dams, and other infrastructure, to the rules and regulations governing coastal development and wetland protection, the decision whether to consider climate change now will have implications down the line.
    • Some systems and societies are more vulnerable to the impacts of climate change than others. For example, some countries such as the U.S. may be better able to adapt to climate change, or have a greater “adaptive capacity” than others. By contrast, the adaptive capacities of many developing countries, or even some regions or localities within the U.S., are often limited by a number of vital factors, such as economic or technological resources. Smart planning ensures that governments and communities are paying attention to those systems that are most vulnerable, while laying the groundwork for actions to reduce the risk to human life, ecosystems, infrastructure, and the economy.


Successful Approaches to Adaptation

  • Recognize that adaptation must happen at local and regional levels. Climate changes and their associated impacts vary greatly from location to location.  Although national and international action is essential, many important decisions about how best to manage systems affected by climate change are made at local and regional levels.
    • For example, states and localities have authority over land use planning decisions, including zoning and building codes, as well as transportation infrastructure. 
  • Adaptation planning requires an understanding of those systems that are most and risk—and why. That means finding answers to questions in three key areas:
    • Exposure: What types of climate changes and impacts can we expect, and which systems will be exposed? What is the possible range of severity of exposure, including the duration, frequency, and magnitude of changes in average climate and extremes?
    • Sensitivity: To what extent is the system (or systems) likely to be affected as a result of projected climate change? For instance, will the impacts be irreversible (such as death, species extinction or ecosystem loss)? What other substantial impacts can be expected (such as extensive property damage or food or water shortages)?
    • Adaptive Capacity: To what extent can the system adapt to possible scenarios of climate change and/or cope with projected impacts? What is feasible in terms of repair, relocation, or restoration of the system? Can the system be made less vulnerable or more resilient?
  • Successful adaptation planning relies on input from, and the alignment of, all key stakeholders. Because the impacts of climate change span entire regions, adaptation planning should involve representatives from federal, state, and local government; science and academia; the private sector; and local communities.
  • For vulnerable systems, prioritizing adaptive measures based on the nature of the projected or observed impacts is vital. The Intergovernmental Panel on Climate Change (IPCC) published a list of criteria to aid in identifying key vulnerabilities. Some of these criteria include:
    • Magnitude: Impacts of large scale (higher number of people or species affected) and/or high-intensity (catastrophic degree of damage caused such as loss of life, loss of biodiversity).
    • Timing: Impacts are expected in the short term and/or are unavoidable in the long term if not addressed. Consider also those impacts with variable and unpredictable timing.
    • Persistence/Reversibility: Impacts resulting in persistent damage (e.g., near permanent water shortage) or irreversible damage (e.g., disintegration of major ice sheets, species extinction).
    • Likelihood/Certainty: Projected impacts or outcomes are likely, with a high degree of confidence (e.g., damage or harm that is clearly caused by rising temperatures or sea-level). The higher the likelihood, the more urgent the need for adaptation.
    • Importance: Systems at risk are of great importance or value to society, such as a city or a major cultural or natural resource.
    • Equity: The poor and vulnerable will likely be hurt the most by climate change, and are the least likely to be able to adapt. Pay special attention to those systems that lack the capacity and resources to adapt.

Due to uncertainties in projected climate changes and in how systems will respond to those changes, adaptation options must be chosen based on a careful assessment of efficacy, risks and costs.


Current Adaptation Planning in the U.S.

  • In the absence of current federal legislation on adaptation, and recognizing the importance of state and local action, states and localities are beginning to act to address the unavoidable impacts that will occur in the decades to come.
  • State Actions: State governments are recognizing the need for broad-scale adaptation planning, and have started taking steps toward this goal.
    • Six states—Arizona, Colorado, North Carolina, South Carolina, Utah and Vermont—acknowledge adaptation within their climate action plans addressing GHG mitigation, recognizing that comprehensive state adaptation plans be created.
    • Eight other states have already started their adaptation planning efforts, in parallel with their mitigation activities; these states include Alaska, California, Florida, Maryland, Massachusetts, New Hampshire, Oregon, and Washington.
    • California Governor Arnold Schwarzenegger signed an executive order in June 2005 calling for biannual updates on climate change impacts facing California, as well as adaptation plans to address these impacts.
    • Check out the C2ES’s Adaptation Planning Brief to learn more about adaptation planning in your region.
  • Local Actions: Hundreds of cities have created climate action plans, with more cities completing their plans every week. As impacts continue to occur in coastal cities, southeast farming communities, and other areas, more localities are calling for adaptation planning. Below are two examples of leading planners for adaptation in the United States:
    • An adaptation planning leader in the U.S. is King County, Washington, home to the city of Seattle. In 2006, this county formed its own inter-departmental climate change adaptation team, building scientific expertise within county departments to ensure that climate change factors were considered in policy, planning and capital investment decisions. The county has considered climate in the development of emergency response plans, water supply planning processes, and all county plans (e.g., river and floodplain management plans).
    • In April 2007, Mayor Michael Bloomberg released his PLANYC: A Greener, Greater New York. In this plan, the Mayor addresses adaptation, recognizing that the results of climate modeling indicate that the city faces tremendous economic and human health risks from storm surges, hurricanes and flooding, in addition to heat waves, wind storms and water contamination. In PLANYC, the Mayor calls for the city to address three adaptation-specific initiatives: critical infrastructure, specific communities at high risk from climate change, and an overall adaptation planning process.  The Mayor announced a climate change task force in August 2008. The group will be responsible for identifying the city’s assets at risk from projected climate change impacts and will develop integrated strategies to secure these assets.
    • Learn more about local adaptation planning at the International Council for Local Environmental Initiatives: Local Governments for Sustainability or check out the C2ES’s Adaptation Planning Brief to learn more about adaptation planning in your region.
  • The Federal Role: Much investment is needed to help state and local governments, municipalities, private businesses, and individuals manage the impacts of climate change. Just as the federal government must act to reduce U.S. emissions and take other steps to mitigate climate change, it must also take action on adaptation. Ways in which the federal government can enable effective adaptation strategies include:
    • Intellectual leadership, research and development: Provide ongoing climate science research, with a focus on impacts, sensitivity and adaptive capacity.
    • Policy and regulation: Require states to include adaptation planning in their policies and update Federal Emergency Preparedness Plans to include potential climate change impacts and set guidelines for state preparedness plans.
    • Coordination: Support coordination and collaboration amongst and between federal, state and local agencies, governments, and private-sector entities, particularly for cross-state or cross-jurisdictional impacts and adaptation planning.
    • Sharing of best practices: Acquire knowledge from countries leading in adaptation efforts and leverage knowledge, skills, resources and technologies to help state and local governments efficiently implement solutions as cost-effectively as possible.
    • Models and planning tools: Provide affordable modeling and adaptation planning tools or technologies to states, municipalities, private sector entities, and communities to help identify sectors at risk and assess vulnerable systems and potential adaptive measures.
    • Education and awareness: Help citizens, communities, and industries understand the risks of climate change impacts and their role in local and regional adaptation efforts. Fund education, training, and awareness programs to ensure citizens are fully informed.
    • Funding: Provide additional resources to states and localities lacking sufficient funding for proactive adaptation planning.

Learn more about adaptation planning at the Center for Climate and Energy Solutions