Pro-Active Adaptation to Unpredicted Climate Change: Challenging Projections

This paper examines NOAA's role and responsibility to provide predictions in support of climate adaptation decisions, the challenges of the requirement for demonstrated skill to accept a prediction method, and the need for a more useful paradigm.

Mandates for climate change adaptation planning exist at international, national, and local levels. Multilateral development banks fund significant adaptation actions through vehicles such as the Green Climate Fund, which may grow to $100B per year by 2020. The US government, through Executive Order, requires federal agencies to develop and implement adaptation plans. Many public stock exchanges require listed companies to report their climate risks and an industry is growing around demands for climate change adaptation services.

To plan correctly for adaptation, an organization must first identify the risks it faces. Adaptation planners frequently draw upon Coupled Model Intercomparison Project (CMIP) General Circulation Model (GCM) projections to characterize future climate risks and plan adaptation. Planners select particular scenarios, commonly misinterpret them as predictions, and nearly invariably do not examine the full suite.

Although CMIP results represent the world's best estimate of what might happen under several possible scenarios of mitigation success (or failure), climate modelers caution against use of CMIP results for adaptation planning since they have no evidence such GCM results demonstrate skill, and they cannot specify the relative likelihood of scenarios. Modelers carefully label GCM results ‘projections' of what might happen to distinguish them from ‘predictions' i.e. expectations of what will happen. Policy makers are expected to, and regularly call for, use of the best available science. Conditional projections cannot serve as ‘best science' for climate adaptation planning, which depends upon risk analysis informed by at least ordinal-scale impact likelihoods. Such ranking is not available. Adaptation efforts should be directed toward expectations of the future, not a future whose likelihood is unknown. Expectations of the future comprise a prediction; adaptation needs prediction. It is consistent with NOAA's mission and goals to address this need but the existing projection/skill paradigm does not suffice.