Extremes, Health, and Change: Developing a Collaborative Framework between Research and Management (Invited Presentation)

The Fourth National Climate Assessment and recent IPCC reports note that the physical and socioeconomic impacts of compound extreme events (such as simultaneous heat and drought, wildfires associated with hot and dry conditions, or flooding associated with high precipitation on top of snow or waterlogged ground) can be greater than the sum of the parts. Moreover, the systematic tendency of climate models to underestimate temperature change during warm paleoclimates suggests that climate models are more likely to underestimate than to overestimate the amount of long-term future change. Emphasizing co-benefits, of adaptation and mitigation efforts, and increasing interagency coordination have long-been identified as critical for effectively addressing both public health and the challenges of increasing climate extremes. Robust detection, attribution, and projection of such events into the future is challenged by multiple factors, including an observational record that often does not represent the full range of physical possibilities in the climate system, as well as the limitations of the statistical tools, scientific understanding, and models used to describe these processes. Traditional risk management methods center upon the abilities to prevent, absorb the impact of, and/or withstand threats usually characterized as discrete events. Unfortunately, this approach can give rise to new vulnerabilities, as systems become more exposed and sensitive, and with less capacity to adapt to unexpected events An important aspect of surprise is the potential for compound extreme events. These can be events that occur at the same time or in sequence (such as consecutive floods in the same region) and in the same geographic location or at multiple locations within a given country or around the world (such as moving from drought to floods in the US Midwest 2011-2013). In addition, complex hazards may consist of multiple extreme events or of events that by themselves may not be extreme but together produce a multi-event occurrence (such as a heat wave accompanied by drought). Compound events may surprise in two ways (1) known types of compound events recur, but are stronger, longer-lasting, and/or more widespread than those experienced in the observational record or projected by model simulations for the future, and (2) the emergence of new types of compound events not observed in the historical record or predicted by model simulations, due to model limitations (in terms of both their spatial resolution as well as their ability to explicitly resolve the physical processes that would result in such compound events), an increase in the frequency of such events from human-induced climate change, or both. These have been delineated into three categories of risks: (i) Those that are well-known cases from the past where a threshold was reached and the management challenges are explicit, and where lessons are available and well documented (ii) Those that are emerging now and often feature aspects of accelerating change or where the accumulation of small change appears to lead to some large change in management or policy response (iii) Those that present very large scale, system-wide challenges-where we know the system well enough, or the science well enough, to think that we really ought to be concerned, that there is are important tipping points/or thresholds The complexity associated with Types (i) and (ii) requires testing the robustness of proposed and/ or actual health management solutions against a range of climate states using decision-relevant objectives to derive performance metrics and identify thresholds (so-called “adaptation tipping points”) beyond which performance may fall below acceptable levels. Much work remains on how to consider risk and resilience in tandem and trade-offs in order to identify optimal allocations of resources. Drawing from the NCA4 and other work, this paper will integrate research and applications of extremes, local contexts and contending perspectives with an understanding of how new information becomes framed and socialized into implementation agendas. The characteristics of extremes related to health issues in urban settings and in Caribbean and Pacific island environments will be used to develop a collaborative framework for assessing complex risks, developing scenarios that include potential surprises, and improving the use of that knowledge in mitigating and managing health related impacts in a changing climate of extremes.