In this workshop, we will present and discuss the experimental design of the planned Tipping Point Model Intercomparison Project (TIPMIP, description paper in preparation).
The aim of TIPMIP is to systematically advance our understanding of tipping dynamics in various Earth system components, and assess the associated uncertainties. TIPMIP specifically aims at answering the following questions:
(1) What is the risk of crossing individual tipping points in the cryosphere, biosphere and core circulation systems at different levels of ongoing climate and land-use change?
(2) What are the key biophysical processes and feedbacks associated with tipping elements?
(3) What are the characteristics (spatial and time scales, abrupt or gradual, etc.) of the individual tipping elements?
(4) Are the respective changes reversible, and if so, on which timescales?
(5) Which are the most critical biophysical feedbacks involved in crossing different tipping points, and between elements affecting the overall stability of the Earth system?
(6) What are the quantitative uncertainties in our assessment of thresholds of tipping points corresponding to various tipping elements and the feedback strengths?
In addressing these questions, TIPMIP will fill critical knowledge gaps in Earth system and climate modelling by improving the assessment of overall anthropogenic forcing and long-term commitments (irreversibilities). It will furthermore foster interdisciplinary knowledge transfer and shed light on critical processes currently underrepresented in Earth-system models and analysis. We will also address a range of more detailed science questions to make progress on process-level attribution, uncertainty, data requirements, and other related issues.
Like other MIPs, we anticipate that TIPMIP will be initially designed to address a few research questions, and would involve a small number of experiments and models. The design of TIPMIP will evolve in the future to address additional science questions and include more experiments and models in successive versions.
Initially, we propose that TIPMIP will conduct three major experiments
(1) a baseline experiment to analyse the historical and projected response of selected tipping elements to different climate and land-use change scenarios,
(2) a commitment experiment to assess the long-term consequences of surpassing different temperature and CO2 levels,
(3) a reversibility experiment to probe the reversibility of impacts and potential hysteresis behaviour.
In Phase 1 of TIPMIP, we will focus on the following tipping elements:
We invite ESMs and “stand-alone” models of different scales and research foci to join this new global effort to assess the potential threat of tipping elements in an innovative way. Successive versions of TIPMIP could be designed to estimate the climate and biogeochemical feedbacks associated with individual tipping elements and quantify the amplification of feedbacks in a cascade of tipping elements.