


Remote Sensing of Tipping Points in the Climate System
Location: Virtual
Dates: January 26-29, 2021
Contact: Sophie Hebden, ESA/ECSAT, United Kingdom; Anny Cazenave, ISSI Bern, Switzerland; Susanne Mecklenburg, ESA/ECSAT, Italy; Lorena Moreira, ISSI Bern, Switzerland; Michael Rast, ESA/ESRIN, Italy

Workshop Overview
The two most recent IPCC Special Reports [1],[2], indicate that climate tipping points – abrupt and irreversible changes in the Earth system – are a risk even at lower global average temperatures. Examples include irreversible melting of Greenland and west Antarctica ice sheets, shutdown of the thermohaline ocean circulation in the North Atlantic, and carbon dioxide and methane release from permafrost melting. Some of these regime shifts could be exceeded between 1 and 2 degrees of warming. A particular threat is cascading tipping effects [3], where exceeding a tipping point in one system triggers abrupt and large-scale change in others.
Since the threat of exceeding climate tipping points cannot be ruled out, they pose an existential threat to civilization and an important frontier for scientific effort: we need to reduce the uncertainties around their likelihood as well as the resilience of the Earth system [4]. Efforts must include developing climate models to capture a richer suite of couplings and feedbacks in the Earth system to anticipate changes and prioritize mitigation efforts. We must also improve our observational records of the most sensitive aspects of the climate system and find more efficient ways to use these observations.
With this 2-3 day forum, we aim to focus on Earth observations, clarifying the satellite data requirements to better monitor the climate system’s resilience to tipping points, to constrain models and build on the ESA CCI programme as a foundation for a future abrupt change early warning system [5]. Workshop participants will contribute to a citable report that will provide input to and guide the development of future ESA climate activities.
The meeting is jointly organized by the ESA Climate Office, International Space Science Institute, and the AIMES (Analysis, Integration and Modeling of the Earth System) global research project of Future Earth.
Scope
Research Questions To Drive The Agenda
- Satellite observation requirements for monitoring tipping elements in the Earth System, perturbing factors, and interactions.
- Processing the data to show proximity to thresholds in the system.
- Development of risk (and resilience) indicators, grouped by sphere into cryosphere, ocean and biosphere – and their interactions, and how they link into social responses and social tipping point risks.
- For biosphere: recommendations for ecological indicators of abrupt change and response to disturbance: observation requirements by region/variable/resolutions to observe greening/browning, fire response, vegetation-atmosphere interactions, and drivers of extinction.
- Cryosphere: prioritization and recommendations for indicators of abrupt change and the inclusion of cascading impacts in models.
- Ocean: critical needs for observation of circulation changes, tipping points relating to ocean-atmosphere fluxes, clouds, and their cascading impacts: for example on hypopoxy and CH4 release.
- System responses to human activity – recommendations for monitoring of tipping elements relating due to land and ocean management.
- Recommendations for improving our understanding of uncertainties and risk relating to remote sensing of tipping elements, and model-data integration.
- Improving our understanding of inter-connectedness of climate and human systems.
- Recommendations for how to use Artificial Intelligence and Machine Learning for detecting tipping thresholds and ‘flickering’ in remote sensing data.
- Research strategies for monitoring unobservable tipping elements through by defining emergent constraints.
- Defining model-data integration requirements, processing and infrastructure.
Agenda
Participants
Organizing Committee
- Susanne Mecklenburg (ESA/ECSAT)
- Sophie Hebden (ESA/ECSAT)
- Anny Cazenave (ISSI)
- Michael Rast (ESA/ESRIN)
- Tim Lenton (University of Exeter, UK)
- Victor Brovkin (MPI-M, Germany)
- Philippe Ciais (LSCE, France)
- Ricarda Winkelmann (PIK, Germany)