Just 32 fossil fuel companies were responsible for half the global carbon dioxide emissions driving the climate crisis in 2024, down from 36 a year earlier, a report has revealed.

Saudi Aramco was the biggest state-controlled polluter and ExxonMobil was the largest investor-owned polluter. Critics accused the leading fossil fuel companies of “sabotaging climate action” and “being on the wrong side of history” but said the emissions data was increasingly being used to hold the companies accountable.

State-owned fossil fuel producers made up 17 of the top 20 emitters in the Carbon Majors report, which the authors said underscored the political barriers to tackling global heating. All 17 are controlled by countries that opposed a proposed fossil fuel phaseout at the Cop30 UN climate summit in December, including Saudi Arabia, Russia, China, Iran, the United Arab Emirates and India. More than 80 other nations had backed the phaseout plan.

Saudi Aramco was responsible for 1.7bn tonnes of CO2, much of it from exported oil. If it were a country, Aramco would be the world’s fifth biggest carbon polluter, just behind Russia. ExxonMobil’s fossil fuel production led to 610m tonnes of CO2 – it would be the ninth biggest polluter, ahead of South Korea.