Statement On Draft Prospectus For The Fifth National Climate Assessment (NCA5)
(click to view the full statement on Draft Prospectus For The Fifth National Climate Assessment)
The U.S. Global Change Research Program, charged with coordinating the United States' research approach around human-induced and natural processes of global change, is currently developing its Fifth National Climate Assessment (NCA5), which is anticipated to be delivered in 2023. This quadrennial assessment analyzes the effects and trends of natural and anthropogenic impacts on the environment.
In order to be transparent and inclusive, the NCA5 will undergo an extensive process of review from federal agency experts, the general public, and an expert panel established by the National Academies of Sciences, Engineering, and Medicine. SilverLining has actively participated in this process, offering input on the assessment's key aspects.
SilverLining submitted public comments to the U.S. Global Change Research Program on its proposed themes and framework for NCA5, focusing on the following recommendations:
Center the analysis on safety,
Expand coverage of near-term abrupt change risks, and
Include assessments of rapid response alternatives, such as solar climate intervention.
SilverLining's general comments on the prospectus are below, responding to each of the following sections:
Introduction and Context for NCA5
Foundational Physical and Biological Science
Human Health and Welfare, Societal, and Environmental Vulnerabilities to a Changing Climate
Regional Analyses Within the United States
Information Needed to Support Climate Change Adaptation, Increased Resiliency, and Risk Reduction
General Comments on the Prospectus
The NCA5 should emphasize safety as a major theme. The GCRA scopes the definition of "Global Change" as those that may "alter the capacity of the Earth to sustain life." The idea of safety is embedded deeply in the notions of harm, well-being, and adverse effects on human health and ecosystems found by Congress and enumerated in the Findings and Purpose of the GCRA. The current framing of Global Change as discrete climate impacts and narrowly-conceived social and ecosystem vulnerabilities has been and continues to be an inadequate characterization for policymakers and communities. Further, as the NCA4's key findings discuss, current research and recent experience demonstrates that the interconnection between modern globalized society and natural systems is high in both magnitude and complexity, increasing the scientific challenge of isolating predicted changes on particular populations, and reducing the practical utility of distinguishing between anthropogenic and natural earth system changes.
Instead, NCA5 should recognize that the overarching goal of a safe and stable climate must account for trends and processes that increase or decrease climate safety, regardless of causal "origin". For example, clean energy build-out will reduce the long-run concentration of GHGs, but increase the short-term warming effect of GHGs already emitted, via reduction of the reflective effect of atmospheric aerosols from pollution. Similarly, the uncertain near-term risk of abrupt irreversible changes in major natural systemseven if anthropogenic emissions are rapidly reduced to zero or negative, may necessitate fast-acting technological interventions in the climate system to protect societies and ecosystems that exist today, regardless of medium- to long-term emissions pathways.
Characterizing the trends and risks of global change in terms of "safety" is both more accurate in terms of acknowledging the tractability of current uncertainties and the scale of scientific efforts needed to address them, and more valuable for policymakers and stakeholders who must make costly investments and life-or-death risk-management decisions.
It is important to note the considerable uncertainty pertaining to the ability of adaptation measures as commonly characterized to ensure the safety of U.S. and global populations and the sustainability of the natural systems they rely on. As climate impacts escalate, large-scale technological intervention to reduce warming, such as increasing the reflection of sunlight from the atmosphere by scattering particles in the stratosphere or brightening clouds - i.e. "solar climate intervention" - may be relevant to near-term safety, and has become an area of increased attention among U.S. and international policy-makers and scientists.
Record levels of warming and observations of rapid changes in natural systems suggest growing near-term risks of abrupt changes in major natural systems –– e.g. methane release from permafrost, collapse of major ice sheets –– with the potential for catastrophic consequences. As such, NCA5 should examine closely national and global capabilities for observing and predicting major abrupt changes and assessing the potential of rapid interventions to reduce these risks.
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