What company has the biggest carbon footprint?
Saudi Aramco is widely regarded as the largest corporate emitter when looking at direct emissions from operations (Scope 1) and purchased electricity (Scope 2). When you include emissions from the use of sold products (Scope 3), rankings can shift, and other oil majors—like ExxonMobil, CNPC, and Sinopec—often appear near the top depending on the year and methodology.
How the carbon footprint of a company is measured
Emissions are tracked using a standardized framework that separates direct operations, electricity supply, and the broader life cycle of a company’s products. Scope 1 covers direct emissions from owned or controlled sources. Scope 2 accounts for indirect emissions from purchased electricity, heat, and steam. Scope 3 encompasses all other indirect emissions along the value chain, including product use by customers. Rankings vary by which scopes are included, the year of measurement, and the data sources used by researchers and companies.
Top emitters by direct emissions (Scope 1 and 2)
These figures reflect the largest sources of greenhouse gases from a company’s own operations and energy use, excluding the downstream impact of how products are used. The rankings below are based on credible studies and corporate disclosures and can vary year to year.
- Saudi Aramco — typically the largest emitter by Scope 1 and 2 emissions, due to its vast oil and gas operations.
- China National Petroleum Corporation (CNPC) — among the top emitters in Scope 1 and 2 because of extensive upstream activities and refining operations.
- Sinopec — another major oil major with sizable Scope 1 and 2 emissions.
- ExxonMobil — consistently one of the leading emitters in Scope 1 and 2.
- BP — among the top five for direct emissions in many years.
In this category, Aramco, CNPC, Sinopec, ExxonMobil, and BP frequently appear at the top, with exact rankings shifting due to annual production levels, energy use, and reporting practices.
Top emitters when including Scope 3 (emissions from product use and the broader value chain)
When taking into account the full life cycle of products—especially the use phase of fossil fuels—the rankings can change dramatically. Scope 3 emissions tend to dwarf Scope 1 and 2 for major oil producers because they include the emissions generated when customers burn the fuels sold by these companies.
- Saudi Aramco — often the largest or among the largest when Scope 3 is included, reflecting the volume of fossil fuels sold and their end-use impacts.
- ExxonMobil — frequently among the top five due to its large production scale and global market reach.
- CNPC — another major player with substantial Scope 3 impact from oil and gas products distributed internationally.
- Sinopec — a leading contributor in Scope 3 because of its global refining and product distribution network.
- Shell or BP — depending on the year and methodology, Shell and BP are often cited among the top five for Scope 3 emissions due to product-use impacts.
Scope 3 rankings are highly sensitive to how data are estimated, what products are included, and the year in question. Analysts and researchers frequently update these figures as more complete disclosures become available.
Why rankings vary and how to interpret them
Differences in methodology, scope coverage, and year of analysis explain why lists of “the biggest carbon footprint” are not a fixed ranking. Some studies emphasize only company-owned emissions (Scope 1 and 2), while others attempt to quantify the full lifecycle impact (Scope 1–3). Data sources include corporate sustainability reports, CDP disclosures, and independent analyses like the Climate Accountability Institute. Given the evolving energy mix and annual reporting changes, today’s top emitter can differ from yesterday’s.
Summary
In short, Saudi Aramco is generally recognized as the largest corporate emitter when evaluating direct emissions from a company’s own operations and energy use. When Scope 3 emissions—driven by the end-use of sold products—are included, the ranking becomes more dynamic, with ExxonMobil, CNPC, Sinopec, and others also competing for the top spots. The exact order depends on the year, data sources, and whether the focus is on Scope 1–2 or Scope 1–3 emissions. As reporting standards evolve and more companies disclose complete data, the public record will continue to refine who sits at the top.
