Fourth National Climate Assessment – NCA Volume II: Initial comments

U.S. Fourth National Climate Assessment - NCA4

I have been working my way through this impressive report and will be commenting in detail on each of its sections in the coming weeks. However, I thought it would be useful to give some background to the report (all 1,656 pages) and to pull out some the general findings before going into the specifics.

This is Volume II of the Fourth National Climate Assessment (NCA4) – Impacts, Risks and Adaptation in the United States, and follows on from Volume I Climate Science Special Report that was published in 2017. 

Report authors

Preparation of the NCA4 has been the responsibility of the Subcommittee on Global Change Research (SGCR).

The report has been written by over 300 Federal and non-Federal authors. Some the organizations involved include:

A pretty impressive list.

The report review process

The draft report has been taken through a rigorous review process involving 8 stages:

  1. December 2016 – review of Chapter outlines by the Federal Steering Committee
  2. A review of annotated outlines by the SGCR
  3. A technical and editorial review by the NOAA
  4. A second review by the SGCR
  5. Draft released for public comment
  6. November 2017 – Review by an expert panel the National Academy of Sciences, Engineering and Medicine 
  7. May 2018 – Final NCA review and clearance
  8. Summer 2018 – A final round of technical and editorial reviews by the NCA leadership and the NOAA and a ‘showstopper’ review that included the authors of the report in Autumn 2018. 

A pretty impressive review procedure.

General findings

  • Earth’s climate is now changing faster than at any point in the history of modern civilisation.
  • This change is primarily the result of human activity.
  • The impacts of these changes are already being felt in the USA and are projected to intensify in the future.
  • The severity of future impacts of change depends upon two factors:
    • whether the emission of greenhouse gases are reduced or not.
    • the extent to which we can adapt to these changes
  • The risks of climate change are recognised by some in the USA who are taking actions (for example) to:
    • counter increasing drought conditions
    • aid the recovery of corals from bleaching caused by warmer waters
    • prevent flooding caused by increasing rainfall 
    • reduce erosion and nutrient losses from agricultural soils caused by increasing rainfall.
  • Climate-related risks will continue to grow unless remedial action is taken
  • Decisions taken today will determine the level of risk for this and future generations
  • Current mitigation actions and efforts to adapt to predicted changes are not at the necessary scale to avoid substantial damage to the U.S. economy, environment, human health and well-being over the coming decades.

My initial comment

This is a serious and extremely concerning report. It is the responsibility of everyone to act on its conclusions and recommendations.

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