Ocean-Climate Nexus - Importance of Ocean Observing for Tipping Points, and the downstream effects of Tipping Points

Tipping points in the Earth's climate can cause catastrophic consequences for ecosystems, biodiversity, and societies. But the knowledge about climate tipping points is still limited. Key knowledge gaps are the identification of the precursors of tipping points, the understanding of their downstream effects, and the development of reliable early warning indicators for climate adaptation and mitigation strategies. The current understanding of tipping points relies on climate models that only partially represent the range of processes, interactions and feedbacks across the entire Earth system. The projects TipESM and ClimTip develop simulations to study tipping points and address these knowledge gaps. They utilize the most advanced Earth System Models (ESMs), which integrate novel in situ observations (from OCEAN:ICE), physical climate models, and key elements such as the continental. ice sheets, marine ecosystems, permafrost, vegetation dynamics and more. ObsSea4Clim provides further improvements of Essential Ocean Variables and Essential Climate Variables to reduce the uncertainty in climate projections of the ESMs. Running experiments across this community requires commonality in diagnostics and experiment protocols (e.g. following CMIP6/7 standards). Therefore, their development is a key effort across the projects. The work of TipESM, ClimTip, OCEAN:ICE and ObsSea4Clim highlights the
importance of ocean observation for improved understanding of climate and its tipping points. By combining the knowledge gained from the ESMs with observations, dynamical theory, and societal and ecological impact models, it is
possible to assess the risks of exceeding key tipping points and the consequences of tipping on Earth systems, ecology and societies. The session will reflect on the importance of international science collaboration and the use of experiment protocols jointly agreed upon by the community. Individual speakers will focus on specific aspects within their expertise, but together these presentations will provide a coherent overview of the interconnectedness and complexity of the ocean and climate on the global scale.