Governments’ knowledge of climate change is central to climate accountability. As climate impacts intensify, litigation accelerates, and one year after the International Court of Justice’s landmark advisory opinion, which clarified States’ obligations to prevent, address, and remedy climate harm, one critical question remains: when did governments know enough to act? While decades of research have exposed what fossil fuel companies knew about the dangers of their products, far less attention has been paid to the states’ historical knowledge. Yet establishing when governments recognized the risks of fossil-fuel-driven climate change is essential to determining the scope of their legal obligations and their responsibility for decades of climate inaction.
“Early Warnings: Government Knowledge of Climate Change and Legal Responsibility for Climate Harm” examines publicly available government records, scientific evidence, and historical archives to document when major emitting States became aware of the causes and foreseeable consequences of climate change. It demonstrates that many governments understood the risks decades earlier than they have claimed, strengthening the evidentiary foundation for climate litigation, human rights, and climate advocacy, and the implementation of the ICJ climate advisory opinion. By tracing the history of government knowledge, the report provides a critical resource for advancing climate accountability and ensuring that high-emitting States are held responsible for failing to prevent the climate crisis.