A recent report has raised concerns that the United Kingdom could face significant financial risks, potentially amounting to national bankruptcy, as foreign states seek legal claims for greenhouse gas emissions dating back to the Industrial Revolution. The analysis warns that an advisory opinion issued by the International Court of Justice (ICJ) last year, which was later endorsed by the United Nations General Assembly, may pave the way for a surge in climate-related lawsuits targeting the UK.

The Policy Exchange report highlights that underdeveloped countries and other parties could argue the UK has breached international obligations related to climate change, resulting in demands for reparations. The authors estimate that if the UK were held responsible for approximately 3% of global historical emissions, the financial liabilities could exceed £4 trillion. The report describes these potential claims as a “new wave of litigation” posing colossal financial risks and urges the UK government to take swift measures to safeguard the country’s interests.

Concerns have also been raised about the potential impact of the ICJ opinion on domestic energy policy, with fears that it could be used to block new oil and gas licenses in the North Sea. The report suggests the UK should consider withdrawing from the ICJ’s compulsory jurisdiction to avoid further exposure to international legal proceedings.

Former Foreign Secretary Sir Malcolm Rifkind criticized the idea of targeting the UK for climate reparations, calling it “ridiculous.” He noted that the Industrial Revolution began in Britain and drove unprecedented economic growth and global poverty reduction. Rifkind argued that much of the recent increase in emissions has come from large, populous countries such as China, India, and Japan, which have followed the path of industrialization pioneered by Britain, Europe, and the United States.

In response to the report, former Supreme Court Justice Lord Sumption emphasized the role of courts in interpreting—not creating—law, stating, “The function of a court of law, whether international or domestic, is to declare the law as it is and not as its judges conceive it ought to be.” The debate highlights the growing tension between evolving international climate norms and established legal frameworks as countries grapple with the legacy of historical emissions and their responsibilities under international law.