Forums are informal and free debates among some fifteen to twenty-five high-level participants on open questions of scientific nature or science policy matters. Forums do not necessarily lead to formal recommendations or decisions. They are generally held once a year at ISSI for two days.


Ground and Space Astronomy: Challenges and Synergies (18 and 19 November  2021)

Astronomy is developing with the combination of data provided by space platforms and ground based observatories, across the electromagnetic spectrum as well as, more recently, by means of high-energy particles and gravitational waves. The current development of large ground-based observatories and more complex space missions, requires considering the benefits of their complementarity for the sake of science excellence.

For this purpose, it is important to review the synergies and the need for cooperation, as it is the case in the new multi-messenger astronomy, but also to identify the challenges to advance further and how to mitigate potential difficulties. Examples of the challenges to be addressed includes, exchange of information, coordination of mutual support, open data access, response to alerts, time allocation or the evaluation of joint proposals.

On the other hand, facilities in space are currently large and expensive, but also the new ground-based large facilities demand important public resources. The identification of the big scientific questions and how they can be better addressed, should thus involve both space and ground-based projects in their roadmaps. The discussion of new elements and the establishment of long-term plans have to be formulated taking into account the full exploitation of both, showing to decision-makers and efficient use of the funding.

The purpose of this Forum is to share ideas among a number of experts to facilitate and encourage coordination in the preparation of astronomy roadmaps and looking for collaboration opportunities in the development, operation and data exploitation of the different, ground and space based, observatories. Particular attention will be devoted to the identification of difficulties in the development of joint activities and how they could be addressed by individual astronomers, national agencies or international entities.

Forum Webpage >>


Tipping Points in the Earth’s Climate (26-29 January 2021)

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. 

Forum Webpage >>

Forum Report >>


[1] IPCC. Global Warming of 1.5°C (IPCC, 2018)

[2] IPCC. IPCC Special Report on the Ocean and Cryosphere in a Changing Climate (IPCC, 2019)

[3] Rocha, J. C., Peterson, G., Bodin, Ö., & Levin, S. (2018). Cascading regime shifts within and across scales. Science , 362 (6421), 1379–1383. 

[4] T. M. Lenton, J. Rockström, O. Gaffney, S. Rahmstorf, K. Richardson, W. Steffen & H.J. Schellnhuber (2019) Climate tipping points — too risky to bet against. Nature, 575, 592

[5] National Academy of SciencesAbrupt Impacts of Climate Change: Anticipating



Towards a Universal Tracers Portal (Date tbd)


Overview of the Past Forums – ISSI Archive Webpage >>