Greenhouse Gas Emissions, Past and Future China, the world's biggest emitter of carbon dioxide, produces 12.7 billion metric tons of emissions annually. That dwarfs U.S. emissions, currently about 5.9 billion tons annually.

As of 2026, China remains the world's largest total polluter in terms of annual carbon dioxide (CO2​) emissions, contributing roughly 33-34% of the global total. This is largely due to its massive industrial manufacturing base and continued reliance on coal for power generation, despite being the world leader in renewable energy installations. However, the answer changes depending on the metric used. If you look at emissions per capita, countries like Palau, Qatar, and Kuwait often rank much higher due to their small populations and massive per-person energy consumption. From a historical perspective, the United States is considered the biggest cumulative polluter, having emitted more total CO2​ into the atmosphere since the Industrial Revolution than any other nation. In the corporate sector, a small group of "Carbon Majors"—primarily state-owned and multinational fossil fuel companies like Saudi Aramco, Gazprom, and ExxonMobil—are identified as being responsible for the vast majority of global industrial emissions.