Global impacts of abrupt climate change: an initial assessment

TitleGlobal impacts of abrupt climate change: an initial assessment
Publication TypeTyndall Working Paper
SeriesTyndall centre Working Papers
Tyndall Consortium Institution

Southampton

Secondary TitleTyndall centre Working Paper 99
Keywordsabrupt climate change, Global impacts, initial assessment
AuthorsArnell, N. W.
Year of Publication2006
Abstract

This report describes the potential global-scale implications of three types of abrupt climate – collapse of the thermohaline circulation, leading to lower temperatures across Europe and parts of North America, and precipitation changes globally (but with effects depending on the degree of warming at the time of collapse), accelerated climate change, leading to very high rates of change in temperature and precipitation, and regime change, where the climate shifts into a state with a permanent El Nino, a permanently wet south Asian monsoon, or a permanently dry south Asian monsoon. Quantitative scenarios, with a high degree of uncertainty, are constructed for each of these types of abrupt change, and used to inform the assessment of potential impacts. The assessment combines some numerical simulations (for water scarcity and energy demand) with interpretation of published studies into the impacts of gradual climate change: the literature on impacts of abrupt climate change is extremely limited. The main implications of the abrupt climate changes are summarised in tables by sector (water, energy, health, agriculture, biodiversity and settlements/infrastructure) and continent, and the concluding section summarises the main implications of each scenario. The most generalised conclusions are: Both thermohaline circulation collapse and accelerated climate change potentially have global-scale consequences, dependent not just on temperature changes but also the pattern of precipitation change. The effects of regime change are more regional, but each of the regime changes considered have the potential to affect world food markets, and hence risk of hunger even in areas not directly affected. The large potential impacts, combined with the non-trivial likelihoods of abrupt climate changes occurring, mean that there is an urgent need for more comprehensive quantitative assessments of abrupt climate change at local and global scales, which can inform more generalised integrated assessments of climate policy. The report does not explicitly consider adaptation, but it is clear that the implications of abrupt climate change for the characteristics of adaptation strategies, and the feasibility of specific adaptation actions, are very large.

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