National Climate Assessment

The U.S. Global Change Research Program (USGCRP) has a legal mandate to conduct a National Climate Assessment (NCA) every four years, the third and most recent of which was released in May 2014. Summarizing current and future climate change impacts across the nation, the NCA is the most comprehensive assessment of climate change impacts ever conducted in the U.S.  The new report is presented on a highly interactive website, with a stunning visual presentation, intended to fully engage the general public along with decision-makers. Links are incorporated into every web page and for each key message, to easily access all supporting evidence including scientific data and related background information. 

The report presents analyses of impacts on seven sectors – human health, water, energy, transportation, agriculture, forests, and ecosystems – and the interactions among sectors at the national level. The report also assesses key impacts on all U.S. regions: Northeast, Southeast and Caribbean, Midwest, Great Plains, Southwest, Northwest, Alaska, Hawai'i and Pacific Islands, as well as the country’s coastal areas, oceans, and marine resources.

This resource was featured in the April 3, 2015, ASAP Newsletter.

"According to the National Climate Assessment, in many regions, climate change will shift precipitation patterns and alter stream flow, increasing competition and decreasing reliability for already limited water supplies – especially in the Great Plains, Southwest, and Northwest.

The lack of rain and snowpack has led the governors of California (2014), Oregon, and Washington to make drought disaster declarations. California just took further steps, implementing mandatory watering restrictions and providing $1 billion for drought relief and water infrastructure."

A team of more than 300 experts guided by a 60-member Federal Advisory Committee produced the report, which was extensively reviewed by the public and experts, including federal agencies and a panel of the National Academy of Sciences.

The opening “Our Changing Climate” chapter presents 12 key messages about the changing climate, along with supporting evidence for those messages. The discussion of each key message begins with a summary of recent variations or trends, followed by projections of the corresponding changes for the future. 

The third NCA report differs from previous U.S. climate assessments in a number of ways. It includes climate impacts and projections, but also assesses progress in response activities such as adaptation and mitigation, each having a dedicated chapter in the report. National indicators of change within regions and sectors are developed, along with consistent and ongoing methods for evaluation - creating an iterative process for the report which will be periodically updated. The focus on a continual assessment process means regional and sectoral activities are expected to be ongoing, and reports will be produced on a more frequent basis.  Also, this NCA report is entirely web?based and the final report has been formatted as an e?book. This allows easier access to data and transparent “line of sight” between data and conclusions (where the user can click on a chart and find the source data, for example).

In addition to an extensive review of climate change impacts and extreme weather events by sector and region, the NCA summarizes climate adaptation efforts across the country in the adaptation chapter. This chapter highlights efforts at the federal, regional, state, tribal, and local levels, as well as initiatives in the corporate and non-governmental sectors to build adaptive capacity and resilience in response to climate change.

One of the key messages of the adaptation chapter is that barriers to implementation of adaptation include limited funding, policy and legal impediments, and difficulty in anticipating climate-related changes at local scales. On the bright side, the assessment found that climate change adaptation actions often fulfill other societal goals, such as sustainable development, disaster risk reduction, or improvements in quality of life, and can, therefore, be incorporated into existing decision-making processes.

For the first time, the NCA firmly concludes that human influences are the primary driver of recent climate change. The majority of the warming at the global scale over the past 50 years can only be explained by the effects of human influences, especially the emissions from burning fossil fuels (coal, oil, and natural gas) and from deforestation.

Also new this year is the focus on a sustained assessment process. The “sustained assessment” is intended to facilitate the continuous and transparent participation of scientists and stakeholders across regions and sectors, enabling new information and insights to be synthesized as they emerge. Additional details about the components of the sustained assessment process are provided in “Preparing the Nation for Change: Building a Sustained National Climate Assessment Process,” the first special report of the National Climate Assessment and Development Advisory Committee.

The “Highlights” report provides a concise version of the full report including an Overview, select evidence for the 12 Report Findings, and summaries of the impacts of climate change on every region of the U.S.

The World Resources Institute has posted an excellent summary of the NCA on their climate blog (May 6, 2014)


If you have any trouble accessing the website link above, please find here an archived page. You may find this has limited use. 

Publication Date: May 6, 2014

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  • Assessment
  • Climate science


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