A framework to diagnose barriers to climate change adaptation.

This article presents a systematic framework to identify barriers that may impede the process of adaptation to climate change. The framework targets the process of planned adaptation and focuses on potentially challenging but malleable barriers. Three key sets of components create the architecture for the framework. First, a staged depiction of an idealized, rational approach to adaptation decision-making makes up the process component. Second, a set of interconnected structural elements includes the actors, the larger context in which they function (e.g., governance), and the object on which they act (the system of concern that is exposed to climate change). At each of these stages, we ask (i) what could impede the adaptation process and (ii) how do the actors, context, and system of concern contribute to the barrier. To facilitate the identification of barriers, we provide a series of diagnostic questions. Third, the framework is completed by a simple matrix to help locate points of intervention to overcome a given barrier. It provides a systematic starting point for answering critical questions about how to support climate change adaptation at all levels of decision-making.

The long arm of climate change: societal teleconnections and the future of climate change impacts studies.

"Societal teleconnections" - analogous to physical teleconnections such as El Niño - are human-created linkages that link activities, trends, and disruptions across large distances, such that locations spatially separated from the locus of an event can experience a variety of impacts from it nevertheless. In the climate change context, such societal teleconnections add a layer of risk that is currently neither fully appreciated in most impacts or vulnerability assessments nor in on-the-ground adaptation planning. Conceptually, societal teleconnections arise from the interactions among actors, and the institutions that guide their actions, affecting the movement of various substances through different structures and processes. Empirically, they arise out of societal interactions, including globalization, to create, amplify, and sometimes attenuate climate change vulnerabilities and impacts in regions far from those where a climatic extreme or change occurs. This paper introduces a simple but systematic way to conceptualize societal teleconnections and then highlights and explores eight unique but interrelated types of societal teleconnections with selected examples: (1) trade and economic exchange, (2) insurance and reinsurance, (3) energy systems, (4) food systems; (5) human health, (6) population migration, (7) communication, and (8) strategic alliances and military interactions. The paper encourages further research to better understand the causal chains behind socially teleconnected impacts, and to identify ways to routinely integrate their consideration in impacts/vulnerability assessment and adaptation planning to limit the risk of costly impacts.

Emissions pathways, climate change, and impacts on California.

The magnitude of future climate change depends substantially on the greenhouse gas emission pathways we choose. Here we explore the implications of the highest and lowest Intergovernmental Panel on Climate Change emissions pathways for climate change and associated impacts in California. Based on climate projections from two state-of-the-art climate models with low and medium sensitivity (Parallel Climate Model and Hadley Centre Climate Model, version 3, respectively), we find that annual temperature increases nearly double from the lower B1 to the higher A1fi emissions scenario before 2100. Three of four simulations also show greater increases in summer temperatures as compared with winter. Extreme heat and the associated impacts on a range of temperature-sensitive sectors are substantially greater under the higher emissions scenario, with some interscenario differences apparent before midcentury. By the end of the century under the B1 scenario, heatwaves and extreme heat in Los Angeles quadruple in frequency while heat-related mortality increases two to three times; alpine/subalpine forests are reduced by 50-75%; and Sierra snowpack is reduced 30-70%. Under A1fi, heatwaves in Los Angeles are six to eight times more frequent, with heat-related excess mortality increasing five to seven times; alpine/subalpine forests are reduced by 75-90%; and snowpack declines 73-90%, with cascading impacts on runoff and streamflow that, combined with projected modest declines in winter precipitation, could fundamentally disrupt California's water rights system. Although interscenario differences in climate impacts and costs of adaptation emerge mainly in the second half of the century, they are strongly dependent on emissions from preceding decades.