Potential tipping points for climate change adaptation costs

ABSTRACT The achievement of adaptation objectives will require increased investment with the increasing warming, but adaptation cost curves are not yet well quantified. We propose here that tipping points (sharp increases) in adaptation costs may emerge as key warming levels are exceeded, with important implications for policymakers and planners. We explore this proposition using selected African agriculture and ecosystem-based livelihoods examples, considering how adaptation responses might progress from a coping phase (with low-cost efforts), through a tipping point into a phase of proactive or planned (‘incremental’) adaptation that requires a sharp increase in adaptation investment, and through a further tipping point into a technology and capital-intensive (‘transformative’) phase requiring a further sharp increase in investment. Tipping points in adaptation costs may result as a series of limits to adaptation are breached, but the associated sharp cost transitions are not well recognized in the literature. Adaptation research could usefully focus on identifying the likely timing of these tipping points and in what sectors they may occur. Emerging analyses of joint mitigation/adaptation response options may need to account for these tipping points.