Planting Trees Alone Can’t Offset Big Oil’s Carbon Emissions, Study Finds

Planting trees offers undeniable climate benefits, but relying on them alone to counterbalance the emissions from the world’s largest fossil fuel companies is a mathematical impossibility, according to a new study published Thursday in Communications Earth & Environment, a Nature Portfolio journal.

To fully offset the carbon emissions that would result from burning the fossil fuel reserves held by the world’s 200 largest oil, gas, and coal companies, trees would need to cover the entire land area of North and Central America. Even then, the effort would fall short, the study finds.

“Removing carbon is essential, not just reducing it,” said Nina Friggens, a research fellow at the University of Exeter and co-author of the study. “But trees simply can’t absorb enough to match the scale of emissions from fossil fuel reserves.”

Carbon offsetting, often marketed by corporations as a climate solution, involves funding projects such as tree planting to compensate for greenhouse gas emissions. Trees are widely seen as a cost-effective option since they naturally absorb carbon dioxide through photosynthesis. However, when researchers calculated the carbon-removal capacity of trees versus the potential emissions from existing fossil fuel reserves, they found the gap to be unbridgeable.

The researchers estimated that planting enough trees to offset those emissions would cost $10.8 trillion—far more than the combined market value of the fossil fuel companies, which stands at $7.01 trillion. Additionally, if companies were forced to pay for the social cost of their carbon reserves—estimated at $185 per metric ton of CO₂—they’d be deep in the red.

“The general public may see carbon offsetting as a magic eraser, but that’s just not where we are,” said Friggens.

Energy giants such as TotalEnergies tout investments in carbon capture and nature-based solutions, but the study argues that these efforts are no match for the scale of emissions if fossil fuel extraction continues.

Forestry expert Éliane Ubalijoro, CEO of international research body CIFOR-ICRAF, praised the study as “elegant” and helpful in illustrating the scale of the challenge. But she warned against looking at tree planting solely as a carbon fix, noting its broader benefits—like promoting biodiversity, food security, and resilience to climate disasters—when done correctly.

Daphne Yin, director of land policy at Carbon180, emphasized the study’s core message: “It’s financially and physically impossible to offset enough carbon to allow continued fossil fuel burning. That’s the reality.”

Jonathan Foley, executive director of Project Drawdown, who was not involved in the research, compared the situation to an overflowing bathtub. “Trees are the mops and sponges we use to clean up the mess,” he said. “But if the tap is still running, we need to stop the water first. Offsetting isn’t a substitute for cutting emissions.”