There is increasing realization and concern that human modification of the Earth system runs the risk of inducing abrupt transitions in climate, ocean circulation, the cryosphere, ecosystems, and society. Our ability to predict when and where such transitions, so called “tipping points,” might happen is limited. While abrupt climate change has long been identified in ice core records (Johnsen et al., 1992) and other archives, skillfully modeling abrupt change has largely been limited to simple models and many state of the art climate models underestimate the rate and extent of abrupt change apparent in paleo data (Valdes, 2011). Major challenges facing more complex models include simplifying processes through parameterizations and the exclusion of processes important on longer timescales such as ice-sheet dynamics or carbon cycle feedbacks that would give rise to abrupt events. This challenges our ability to understand the ways in which human activities may put pressure on the biogeochemical and physical climate systems to induce tipping points in the future.
Recently, a multi-model assessment revealed abrupt events in some models under forcing from the IPCC RCP scenarios, suggesting the possibility of predicting the likelihood of such events (Drijfhout et al., 2015). Advancing our understanding of the full range of possible abrupt climate, environmental and societal changes through the continued assessment and collection of paleo data and application of robust statistical techniques using improved multimodel experiments will help us to assess future risks. However, how to best use the paleo records in this regard is not well established.
The main objective of this workshop is to summarize and evaluate evidence on non-linear Earth System dynamics in recent geological history, and discuss how best to acquire, analyze and interpret such data to understand the risk of future abrupt transitions. Where applicable, we will discuss physical, biogeochemical, ecological and social processes that might have caused abrupt transitions to new states, and their relevance for Earth system models. We will assess the well-archived and relatively abundant paleoclimate data from the Quaternary period, and the skill of the current state of the art climate models to reconstruct past abrupt changes and predict abrupt climate change in the future.