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The Global Change research Act of 1990 requires that the United States produce a synthesis report on the state of climate science, impacts, and adaptations at least every 4 years. The US Global Change Research Program (USGCRP) is the collaboration of 13 federal agencies and offices responsible for overseeing the production of the NCA. Interestingly, while the US Department of Defense is one of these agencies, FEMA and the Department of Homeland Security are not, because DHS was established after the Global Change Research Act passed. Adding DHS or even FEMA to the USGCRP agencies would require amendment of the Act by Congress.

This synthesis report is known as the National Climate Assessment. It is created with author teams from the government, academic, and non-profit sectors recognized as experts in the field. They use peer-reviewed literature and combine the knowledge into the assessment report.

It has proved challenging to produce the NCA on a 4-year schedule. The Third National Climate Assessment (NCA3) was released in 2014, 6 years after the production of the Second National Climate Assessment in 2009. Prior to the release of NCA3, a Climate Science Special Report was created in 2013 and provided to the authors, who used it as the scientific basis to outline the potential impacts of climate change on numerous sectors and regions and the state of knowledge on adaptation and decision support. The Fourth National Climate Assessment (NCA4) is being produced in two volumes. This round, the Climate Science Special Report was released in November 2017 as NCA4 Volume 1. Early drafts were available to the authors of NCA4 Volume 2, which is to be divided into sectoral chapters (primarily produced by government scientists) and regional chapters, primarily produced by academic authors. NCA4 Volume 2 is scheduled to be released in December 2018, and if this continues to proceed on the timeline without delays it will be the first time that an NCA has been completed within 4 years.

In this module, you will briefly survey Volume 1 of NCA4, focusing on the key messages for selected sectors relevant to EDM. Keep in mind that you are not expected to read every word! Unfortunately, unlike NCA3, NCA4 is not being released with products designed to be more accessible to a non-climate science audience. However, it represents the broadest and most up to date synthesis of climate science for the United States. Focus on reading the overall messages and just skim the main points under the supporting evidence for each message. The purpose of this survey is not for you to learn the intricacies of climate science; rather, it is for you to become familiar with the breadth of impacts so that as questions come up during your own practice or research, you are familiar with what exists and know where to go for more in-depth answers.

Keep in mind the following questions, which will help prepare you to read the course material and engage in our class activities:

What are the main climate forcing mechanisms, and how does the climate respond?
What are the lines of evidence for climate change?
How is climate change impacting climate on a global scale, and what do we know about how it affects large-scale circulations?
How is temperature responding in response to anthropogenic forcing, and how does this vary by location?
What do we know about how precipitation is changing?
How do we study the attribution of extreme storms to climate change?
How does the rate of projected sea level rise vary by location?

Readings, retrieved links open in new tab/window:

Read the following online chapters in Wuebbles, D.J., D.W. Fahey, K.A. Hibbard, D.J. Dokken, B.C. Stewart, and T.K. Maycock (Eds.). (2017). Climate Science Special Report: Fourth National Climate Assessment, Volume I. Washington, DC: U.S. Global Change Research Program. Remember, you are focusing your reading at the level of key takeaways, NOT in-depth analysis.

Lines of evidence on climate change

Chapter 2. Physical drivers of climate change. Authors: Fahey, D.W., S.J. Doherty, K.A. Hibbard, A. Romanou, and P.C. Taylor.
Chapter 3. Detection and attribution. Authors: Knutson, T., J.P. Kossin, C. Mears, J. Perlwitz, and M.F. Wehner.

Physical indicators of climate change

Page 5 of 12 in Module 1