U.S. Climate Resilience Toolkit

This report and the accompanying community spotlights provide an overview of climate change science, reasons why action is needed, how science supports decision making and planning, ways to adapt to climate change and limit the severity of its effects, and how such efforts can help build resiliency. The report illustrates the ways in which science can help individuals, communities, businesses, and government agencies make informed decisions. By working together to identify solutions and bring about positive change, we can reduce the risks faced by current and future generations.

The Global Change Research Act of 1990 mandates that the U.S. Global Change Research Program deliver a report to Congress and the President no less than every four years that “1) integrates, evaluates, and interprets the findings of the Program…; 2) analyzes the effects of global change on the natural environment, agriculture, energy production and use, land and water resources, transportation, human health and welfare, human social systems, and biological diversity; and 3) analyzes current trends in global change, both human-induced and natural, and projects major trends for the subsequent 25 to 100 years.” The Fourth National Climate Assessment (NCA4) fulfills that mandate in two volumes. This report, Volume II, draws on the foundational science described in Volume I, the Climate Science Special Report. Volume II focuses on the human welfare, societal, and environmental elements of climate change and variability for 10 regions and 18 national topics, with particular attention paid to observed and projected risks, impacts, consideration of risk reduction, and implications under different mitigation pathways. Where possible, NCA4 Volume II provides examples of actions underway in communities across the United States to reduce the risks associated with climate change, increase resilience, and improve livelihoods. This assessment was written to help inform decision makers, utility and natural resource managers, public health officials, emergency planners, and other stakeholders by providing a thorough examination of the effects of climate change on the United States.

As a key part of the Fourth National Climate Assessment (NCA4), the U.S. Global Change Research Program (USGCRP) oversaw the production of this stand-alone report of the state of science relating to climate change and its physical impacts. The Climate Science Special Report (CSSR) is designed to be an authoritative assessment of the science of climate change, with a focus on the United States, to serve as the foundation for efforts to assess climate-related risks and inform decision making about responses. 

As Volume 1 of NCA4, CSSR serves several purposes, including providing (1) an updated and detailed analysis of the findings of how climate change is affecting weather and climate across the United States; (2) an executive summary and 15 chapters that provide the basis for the discussion of climate science found in the second volume of NCA4; and (3) foundational information and projections for climate change, including extremes, to improve “end-to-end” consistency in sectoral, regional, and resilience analyses within the second volume. CSSR integrates and evaluates the findings on climate science and discusses the uncertainties associated with these findings. It analyzes current trends in climate change, both human-induced and natural, and projects major trends to the end of this century. As an assessment and analysis of the science, CSSR provides important input to the development of other parts of NCA4, and their primary focus on the human welfare, societal, economic and environmental elements of climate change. Much of the underlying report is written at a level more appropriate for a scientific audience, though the Executive Summary is intended to be accessible to a broader audience. 

This report documents that the average temperature in 2015 was over one degree higher than pre-industrial times and that the period 2011–2015 was the warmest five-year period on record, consistent with established warming trends. The report further documents that in 2015 another milestone was reached, with globally averaged CO₂ levels of 400 parts per million (ppm). The year 2016 is on track to be even warmer and will be the first year in which CO₂ at the Mauna Loa Observatory remains above 400 ppm all year, and for many generations to come.

The probability of extreme climate events since 2011, especially those involving extreme high temperatures, has been substantially increased by climate change, often by a factor of 10 or more. The single most significant event in humanitarian terms, with over 250,000 lives lost, was the 2011–2012 famine in the Horn of Africa, where drought was a major factor.

This report features observed trend data on 37 climate indicators, including U.S and global temperatures, ocean acidity, sea level, river flooding, droughts, and wildfires. It documents rising temperatures, shifting patterns of snow and rainfall, and increasing numbers of extreme climate events, such as heavy rainstorms and record high temperatures. Many of these observed changes are linked to the rising levels of carbon dioxide and other greenhouse gases in our atmosphere, caused by human activities.

Successfully negotiating climate change challenges will require integrating a sound scientific basis for climate preparedness into local planning, resource management, infrastructure, and public health, as well as introducing new strategies to reduce greenhouse gas emissions or increase carbon sequestration into nearly every sector of California’s economy. This Research Plan presents a strategy for developing the requisite knowledge through a targeted body of policy-relevant, California-specific research over three to five years (from early 2014), and determines California’s most critical climate-related research gaps.

The National Climate Assessment assesses the science of climate change and its impacts across the United States, now and throughout this century. It documents climate change-related impacts and responses for various sectors and regions, with the goal of better informing public and private decision making at all levels.

The assessment draws from a large body of scientific peer-reviewed research, technical input reports, and other publicly available sources; all sources meet the standards of the Information Quality Act. The report was extensively reviewed by the public and experts, including a panel of the National Academy of Sciences, the 13 federal agencies of the U.S. Global Change Research Program, and the Federal Committee on Environment, Natural Resources, and Sustainability.

In 2013, the Baltimore City Department of Planning and Office of Sustainability created the Disaster Preparedness and Planning Project (DP3) as an effort to address existing hazards while simultaneously preparing for predicted hazards due to climate change. This project develops an integrated All Hazards Mitigation Plan, floodplain mapping, and Climate Adaptation Plan program that links research, outreach, and actions to assure implementation of a comprehensive and new risk-preparedness system for addressing existing and future impacts. Integrating hazard mitigation planning, which focuses on past events, with climate adaptation planning, which focuses on what will likely happen in the future, offers a positive, win-win solution for Baltimore City.