Against the backdrop of negotiations at COP30 in Belém, a group of leading climate scientists has released the Búzios Scientific Statement, offering a clear assessment of the world’s remaining options to return to 1.5°C of warming by the end of the century. The statement reflects growing recognition that a temporary overshoot of 1.5°C is now unavoidable, while also showing that pathways back to safer temperature levels remain open if action accelerates quickly.
The statement was developed by participants of last week’s annual meeting of the Integrated Assessment Modelling Consortium (IAMC), which took place in parallel with the COP30 negotiations and brought together more than 250 leading climate researchers in Armação dos Búzios, Brazil, to discuss the latest evidence on mitigation and adaptation pathways.
The scientists involved in preparing the statement describe the next decade as decisive. Their work provides guidance at a moment when countries are still debating how to close the ambition gap at COP30, and as small island states call on parties to honor the 1.5°C goal.
“Overshooting 1.5°C is no longer a hypothetical scenario – it is something the world must now navigate,” notes IIASA Energy, Climate, and Environment Program Director, Keywan Riahi, who was a coordinator of the statement. “Our research shows that limiting overshoot and returning below 1.5°C is still possible, but only if emissions fall quickly and clean-energy deployment accelerates. With every delay, the challenge grows and the reliance on carbon removal increases.”
Insights from a novel set of scenarios that will be part of the forthcoming Scenario Compass Initiative database provide a sense of the transformation required by 2035, with global greenhouse gas emissions needing to fall sharply and renewable energy deployment increasing significantly.
The statement highlights five main insights from the latest scenario work:
“The choices made this decade will determine whether overshoot remains manageable,” says IIASA Integrated Climate Impacts Research Group Leader, Carl Schleussner, one of the statement’s coauthors. “Communities around the world are already experiencing serious climate impacts, and only by decisive action on mitigation and adaptation can we get back on track.”
About IIASA:
The International Institute for Applied Systems Analysis (IIASA) is an international scientific institute that conducts research into the critical issues of global environmental, economic, technological, and social change that we face in the twenty-first century. Our findings provide valuable options to policymakers to shape the future of our changing world. IIASA is independent and funded by prestigious research funding agencies in Africa, the Americas, Asia, and Europe. www.iiasa.ac.at