Open Letter "An S.O.S. from the Cryosphere to World Leaders at COP30"

November 10, 2025 

***Endorsement remains open throughout COP30, and the signatory list is updated daily***. 

Please, sign here: https://forms.gle/Z6UkhSCijF6tvsSaA. Only institutional signatures.

We, the undersigned scientific organisations and institutions, call on world leaders meeting in Belém, Brazil, at COP30 to take urgent and decisive action to safeguard the cryosphere – the planet’s ice sheets, glaciers, sea ice, snow cover, and permafrost.

Building on our 2024 appeal “An S.O.S. from the Poles to World Leaders at COP29,” we issue this renewed call as the signs of cryosphere destabilisation have only grown clearer and more alarming.

The evidence is unequivocal: the cryosphere is destabilising at an alarming pace. Melting ice sheets and glaciers are driving sea-level rise; sea-ice loss and permafrost thaw are altering global climate patterns; and these shifts are already affecting ecosystems, water resources, and human security worldwide.

The 1.5 °C limit is not a political aspiration but a planetary guardrail that we are now perilously close to breaching. Crossing this threshold risks triggering irreversible tipping points in the cryosphere, locking in catastrophic impacts for centuries to millennia. Already, early signs of such changes are emerging even at lower levels of warming. 

No engineered climate intervention is a substitute for emission reductions. Some interventions, such as solar radiation management or large-scale albedo modification, will not provide safe or lasting solutions – especially in fragile polar regions where environmental and risk assessments have not been conducted. Such technologies could, at best, mask or temporarily delay some impacts while introducing new and unpredictable dangers. Rapid, deep and sustained emission cuts, complemented by carbon drawdown methods that are shown to be low-risk and beneficial to biodiversity, such as ecosystem restoration and reforestation, is the only viable path to prevent further destabilisation of the cryosphere.

At COP30, where the world will evaluate progress and chart the next decade of climate action, we call on leaders to:

1. Commit to deep and immediate reductions in greenhouse gas emissions, complemented by low-risk carbon drawdown, to place the world on a trajectory to limit warming to 1.5 °C by 2100, without relying on the false hope of large-scale, high-risk climate interventions.

2. Halt the expansion of fossil fuel infrastructure and accelerate just, equitable energy transitions, while reducing emissions from all major sources, including food and agriculture.

3. Deliver scaled and transparent climate finance to meet agreed targets, supporting adaptation and addressing loss and damage in vulnerable, cryosphere-affected regions.

4. Invest in long-term cryosphere monitoring and early-warning systems, ensuring open data, capacity building, and strong scientific collaboration.

Geopolitical tensions or short-term national interests must not overshadow COP30. 

Climate change is the defining security and stability challenge of our time.

The cryosphere may seem remote, but its rapid decline poses a significant threat to every society. There is no more time to waste: immediate, bold, and decisive action is essential for the future of our planet and of humanity.

An Extended Technical Annex of this Open Letter can be found here: https://drive.google.com/file/d/1y-R9bYEZ9Ss0lEeTn_o5D7zGeEG5MrAq/view?usp=sharing.

For any questions, please contact:

Dr. Letizia Tedesco [E: Letizia.Tedesco@environment.fi; Ph: +358 295 251 686].

Dr. Jacqueline Stefels [E: jstefels@rug.nl; Ph: +31 6 311 95 202].

The Undersigned parties

BEPSII: Biogeochemical Exchange Processes at Sea Ice Interfaces; https://www.bepsii.org

ASPeCt: Antarctic Sea ice Processes and Climate; http://aspectsouth.org/

CATCH: the Cryosphere and ATmospheric CHemsitry; https://www.catchscience.org/

PACES: air Pollution in the Arctic: Climate, Environment and Societies; https://pacesproject.org

The Endorsing Institutes and Organisations - Updated 10 November 7 am GMT

Antarctica InSync, Coordinator Dr. Diego Filún.

Arctic Centre at Umeå University, Director Dr. Keith Larson, Sweden.

Arctic Monitoring and Forecasting Center - Copernicus Marine Services, Research Leader Dr. Laurent Bertino. 

Belgian Federal Science Policy (BELSPO), Director Mrs. Maaike Vancauwenberghe, Belgium.

Bolin Centre for Climate Research, Stockholm University, Vice-Director Prof. Gustaf Hugelius, Sweden.

British Antarctic Survey, Director of Science Dr. Petra Heil, UK. 

European Centre for Research and Education in Environmental Geosciences (CEREGE), Director Dr. Lucilla Benedetti, France.

Climate Emergency Institute, Director Dr. Peter Carter, Canada.

Department of Earth Sciences, Graduate School of Science, Chiba University, Head of Department Prof. Toshinori Sato, Japan.

Earth & Life Institute, UCLouvain, Head of the Institute Prof. Dr. Marnik Vanclooster, Belgium.

‘Emil Racovita’ Institute of Speleology, Director Dr. Constantin Marin, Romania.

European Marine Board, Executive Director Prof. Sheila Heymans.

European Polar Board, Chair Prof. Peter Sköld.

Finnish Environment Institute (Syke), Research Director Prof. Eeva Primmer, Finland.

Global Change Research Institute, School of GeoSciences, University of Edinburgh, Deputy Head of Global Change Research Institute Dr. Sian Henley, UK.

High Arctic Institute, President Dr. Kurt Burnham, USA.

Ice and Climate Research Organization (ICRO), Director Dr. Dirk van As, Greenland.

Ikigai Research, Director Dr. Steven Phipps, Australia.

Marine and Antarctic Research for Innovation and Sustainability (MARIS), University of Cape Town, Director Prof. Marcello Vichi, South Africa.

OceanX, Co-CEO, Chief Science Officer Dr. Vincent Pieribone, USA.

REV Ocean, Science Director Dr. Eva Ramirez-Llodra, Norway.

Scientific Committee on Oceanic Research (SCOR) National Committee of Finland, Chair Prof. Petteri Uotila, Finland.

Southern Ocean Observing System (SOOS), Executive Officer Dr. Alyce Hancock.

Surface Ocean - Lower Atmosphere Study (SOLAS), Co-Chair Dr. Christa Marandino.

Tara Ocean Foundation, CEO Mr. Romain Troublé, France.

The Association of Polar Early Career Scientists (APECS), Executive Director Ms. Sarah Marie Strand.

The Australian Centre for Excellence in Antarctic Science (ACEAS), Prof. Matt King, Director, Australia. 

The Japanese Society of Snow and Ice, Prof. Emeritus Nobuhiko Azuma, President, Japan. 

Tvärminne Zoological Station, University of Helsinki, Academic leader Prof. Alf Norkko, Finland.

University of Mirpurkhas, Mr. Javed Ali Kalhoro, In-Charge Chairman, Pakistan.

World Climate Research Programme (WCRP) Climate and Cryosphere (CliC), Executive Officer Dr. Meghan Taylor, USA.