Rethinking adaptation for a 4 ^° C world

TLDR

Global warming of 4 °C is increasingly likely, making long‑term adaptation decisions more uncertain, complex, and transformative, while psychological, social, and institutional barriers risk immobilizing decision‑makers. This study seeks to reduce complexity and uncertainty in 4 °C adaptation by systematically categorizing interactions among decision lifetime, uncertainty type, and adaptation response options. The authors synthesize existing literature to link these interaction categories to a range of risk‑management strategies and tactics. Applying this framework can break down adaptation barriers, simplify and better target decision‑making, but it must be tested and adopted rapidly.

Abstract

With weakening prospects of prompt mitigation, it is increasingly likely that the world will experience 4°C and more of global warming. In such a world, adaptation decisions that have long lead times or that have implications playing out over many decades become more uncertain and complex. Adapting to global warming of 4°C cannot be seen as a mere extrapolation of adaptation to 2°C; it will be a more substantial, continuous and transformative process. However, a variety of psychological, social and institutional barriers to adaptation are exacerbated by uncertainty and long timeframes, with the danger of immobilizing decision-makers. In this paper, we show how complexity and uncertainty can be reduced by a systematic approach to categorizing the interactions between decision lifetime, the type of uncertainty in the relevant drivers of change and the nature of adaptation response options. We synthesize a number of issues previously raised in the literature to link the categories of interactions to a variety of risk-management strategies and tactics. Such application could help to break down some barriers to adaptation and both simplify and better target adaptation decision-making. The approach needs to be tested and adopted rapidly.