Climate Science Glossary

Term Lookup

Enter a term in the search box to find its definition.


Use the controls in the far right panel to increase or decrease the number of terms automatically displayed (or to completely turn that feature off).

Term Lookup


All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Home Arguments Software Resources Comments The Consensus Project Translations About Support

Bluesky Facebook LinkedIn Mastodon MeWe

Twitter YouTube RSS Posts RSS Comments Email Subscribe

Climate's changed before
It's the sun
It's not bad
There is no consensus
It's cooling
Models are unreliable
Temp record is unreliable
Animals and plants can adapt
It hasn't warmed since 1998
Antarctica is gaining ice
View All Arguments...

New? Register here
Forgot your password?

Latest Posts


Early next step: Add risk management to National Climate Assessment

Posted on 14 January 2021 by Guest Author

This is a re-post from Yale Climate Connections by Gary Yohe, Henry Jacoby, Richard Richels, and Benjamin Santer

Imagine a major climate change law passing the U.S. Congress unanimously? Don’t bother. It turns out that you don’t need to imagine it. Get this:

The Global Change Research Act of 1990 was passed unanimously (100-0) in the United States Senate and by voice vote in the House of Representatives. Wow.

The law instructed all relevant federal agencies to intensify their separate research activities into climate change trends, impacts, and uncertainties and to coordinate their efforts under a newly created United States Global Change Research Program (USGCRP). Congress also recognized the need to communicate to the general public the societal and natural vulnerabilities derived directly or indirectly from current or projected climate change. To do that, the law mandated that the federal research community prepare regular national climate assessments (NCAs) to be distributed to the American people every four years by the sitting President.

The first assessment (NCA1), approved and released in November of 2000, effectively began the communication process. It alerted Americans of growing threats posed by human-induced changes in local and regional climates.

Beginning around 2007, risk assessment became the accepted approach to understanding and communicating climate change impacts around the world. NCA3 in 2014 and NCA4 in 2018 therefore instructed writing teams to characterize important climate change effects in terms of the two key principles of risk: the likelihoods of climate change impacts, and their consequences as measured by dollars, lives, other public health metrics, etc.

This risk-based framing meant that national assessments should report high-risk possibilities of all sorts: high-risk circumstances that could, for example, be (1) highly likely to occur with modest to moderate consequences; or (2) more-likely-than-not to occur with more serious consequences; and/or (3) unlikely to occur but with enormous and sometimes calamitous consequences.

By law, the incoming Biden administration will be responsible for preparing the NCA5 for release in 2023, and the time is right for that assessment to advance to the next level by adding risk management to its organizational structure. The new USGCRP assessment team will clearly have to work within the already approved prospectus for NCA5. But unless it pushes itself beyond the boundaries of past assessments, it will not focus stronger attention on how climate risks are being managed now and how they might be managed better in the future.

Moving beyond risk assessment to still more difficult questions

Would that be a step forward? Clearly. Consider, for instance, what it could have added to the key findings about increased vulnerability to coastal flooding reported in NCA4. They included several cautions:

  • Vulnerability had been driven by human-induced sea level rise for decades, but it had not been evenly distributed along the nation’s coastlines;
  • The frequency of high-tide flooding had increased 5- to 10-fold in some communities since 1965, but not in others;
  • Flooding from extreme coastal storms like Nor’easters and hurricanes had generally made landfall with exaggerated storm surges and ponderous rainfall totals over short periods of time; and
  • Adverse impacts from these types of storms are expected to increase as the planet warms over the next century.

NCA4 also estimated that highly cost effective adaptation programs could reduce cumulative discounted future damages to coastal properties across the lower 48 states through 2100 by many billions of dollars, at the very least, and perhaps up to a few trillions of dollars along higher emissions futures.

A focus on risk management in upcoming NCA5 chapters could lead the authors to move beyond these assessments of risks and confront more difficult questions like: “What level of preparation at local, city, state, and regional levels would be required for investment in adaptation to achieve the damage avoidance earlier author teams had suggested would be feasible given changed conditions from those prevalent in 2018? And how might the federal government help (or hinder) in that regard?

NCA4 did present some examples of ongoing efforts to adapt to, mitigate, and provide relief from climate damages, but assessing capacities to manage risk could have brought more critical questions to the fore. For example:

  • Do decision-makers across our federalist system work well together?
  • Do they have and share the necessary information?
  • Are their financial and human resources sufficient?
  • Do bottlenecks or competing agendas impede efforts to reduce net damages?
  • How can public understanding of and trust in climate action be improved?

Lessons learned from pandemic … and meeting growing needs of courts

Finally, consider what management lessons can be drawn from our challenging experiences in trying to manage the COVID-19 pandemic?

A substantial and growing number of insightful documents have been published, notably including the five volumes of America’s Climate Choices. Authors have described and dissected examples of success and of frustration in dealing with all sorts of external threats to human welfare:  There is plenty of material to assess, integrate, and synthesize for the first time to help us fine-tune our capacities to attack climate change over a large and diverse country. Such an approach could lead to including risk management sections in sectoral and regional chapters of NCA5 with analyses that will inform and enhance an expanded adaptation chapter.

Increasing NCA5 attention to risk management is critical also for the judicial system. As climate effects multiply and management responsibilities grow, more cases involving the management of climate risks likely will arise in court dockets across the U.S. The Supreme Court has already charged judges at every level “to determine whether proffered scientific testimony or evidence satisfies the standard of evidentiary reliability” because “a judge must ascertain whether it is ground[ed] in the methods and procedures of science.”

Jurists frequently look to federally prepared scientific reports for guidance in this regard. They will certainly look more frequently to the NCA5 if its coverage of risk management practices provides insights into what might reasonably be expected of plaintiffs or defendants in cases involving climate risks.

More posts in this series

Bringing risk management into the NCA is the next important step in its evolution in communicating climate vulnerabilities to the public. Doing so will illuminate what we know about  incorporating the exploding knowledge of intensifying climate risk into public and private decision-making processes.

Gary Yohe is the Huffington Foundation Professor of Economics and Environmental Studies, Emeritus, at Wesleyan University in Connecticut. He served as convening lead author for multiple chapters and the Synthesis Report for the IPCC from 1990 through 2014 and was vice-chair of the Third U.S. National Climate Assessment.

Henry Jacoby is the William F. Pounds Professor of Management, Emeritus, in the MIT Sloan School of Management and former co-director of the MIT Joint Program on the Science and Policy of Global Change, which is focused on the integration of the natural and social sciences and policy analysis on threats to the global climate.

Richard Richels directed climate change research at the Electric Power Research Institute (EPRI). He served as lead author for multiple chapters of the IPCC in the areas of mitigation, impacts, and adaptation from 1992 through 2014. He also served on the National Assessment Synthesis Team for the first U.S. National Climate Assessment.

Ben Santer served as convening lead author of the climate change detection and attribution chapter of the IPCC’s Second Assessment Report and has contributed to all five IPCC assessments.

0 0

Printable Version  |  Link to this page


There have been no comments posted yet.

You need to be logged in to post a comment. Login via the left margin or if you're new, register here.

The Consensus Project Website


(free to republish)

© Copyright 2024 John Cook
Home | Translations | About Us | Privacy | Contact Us