The entire west world contributes 28.8%. US is about 11%. [1]
[1] https://www.iea.org/reports/global-energy-review-2025/co2-em...
[1] https://www.iea.org/reports/global-energy-review-2025/co2-em...
https://ourworldindata.org/contributed-most-global-co2
> the United States has emitted more CO2 than any other country to date: at around 400 billion tonnes since 1751, it is responsible for 25% of historical emissions; this is twice more than China – the world’s second-largest national contributor