Planting Trees Won’t Cancel Out Fossil Fuels: New Research Warns of Economic and Spatial Limits

Redacción HC
11/09/2025

As climate change accelerates, planting trees has often been promoted as a simple and elegant solution to offset carbon emissions from fossil fuels. Governments, corporations, and investors have embraced tree planting projects, presenting them as a way to “neutralize” carbon while continuing fossil fuel extraction. However, a new study published in Communications Earth & Environment paints a starkly different picture: large-scale afforestation cannot realistically offset fossil fuel emissions when financial viability, land requirements, and ecological risks are considered.

Researchers led by Alain Naef (ESSEC Business School), Nina L. Friggens, Patrick Njeukam, and colleagues examined whether the reserves held by the world’s 200 largest fossil fuel companies could be offset by planting trees. Their analysis reveals that the required scale of afforestation is not only economically unfeasible but also socially and environmentally damaging.

The Research Question: Can Trees Truly Offset Fossil Fuels?

The central question posed by the authors is deceptively simple: is it possible to balance the carbon contained in fossil fuel reserves by planting enough trees? This inquiry matters because tree-planting initiatives have become a cornerstone of corporate climate pledges and public policy frameworks.

Yet, as the authors highlight, the challenge lies not only in how many trees we can plant, but in whether such a strategy is sustainable and fair. Relying heavily on afforestation risks sidelining the urgent need to cut fossil fuel extraction at its source.

How the Study Was Conducted

The study integrates fossil fuel reserve data from Fossil Free Funds with global estimates of forest carbon sequestration potential across different ecosystems. The researchers calculated:

• The total carbon content in reserves of the top 200 fossil fuel companies, equivalent to ~182 gigatons of carbon (~673 Gt CO₂e).
• The land surface required to offset these emissions through tree planting, using spatial models for carbon uptake in various biomes.
• The economic costs under scenarios ranging from $1 to $150 per ton of CO₂, alongside the “social cost of carbon” (estimated around $190/tCO₂).

They also compared afforestation to alternatives such as direct air capture technologies. Key methodological caveats were noted: land availability conflicts with agriculture and conservation, the impermanence of carbon stored in forests due to fires and pests, and the risk of displacement for local communities.

Key Findings: An Impractical Solution

The results are sobering. To offset just the reserves of the companies studied, tree planting would require land equivalent to the combined size of North and Central America. Such a scale would demand sacrificing farmland, displacing communities, and undermining biodiversity.

Financially, the strategy collapses under scrutiny. At carbon prices above $150/tCO₂, the environmental liabilities of fossil fuel companies exceed their current market valuations. Using the higher “social cost of carbon,” the externalities from burning reserves would vastly outweigh corporate worth.

In raw numbers, the costs of offsetting via afforestation are staggering—estimated at $10.8 trillion—while direct air capture, though technologically expensive, is projected at $673.7 trillion. Both figures dwarf the budgets of most governments and corporations, underscoring the impossibility of offsetting fossil fuel use through trees alone.

The authors stress a conceptual point: afforestation is reversible. Unlike geological storage, carbon in forests can return to the atmosphere within decades due to fires, droughts, or logging. This undermines its reliability as a long-term climate solution.

Policy and Social Implications

For policymakers, the study serves as a wake-up call. Designing climate strategies around tree planting as a substitute for emissions cuts is not only impractical but also dangerous. The authors argue for prioritizing fossil fuel reduction at the source—through regulation, taxation, and limits on new extraction—rather than outsourcing responsibility to land and communities.

The social costs are equally significant. Large-scale plantations could threaten food security, disrupt indigenous territories, and erode ecosystem services such as water regulation and pollination. In tropical regions like the Amazon, where carbon uptake is high, the pressure to convert land could exacerbate conflicts over land rights and biodiversity conservation.

The researchers recommend focusing on protecting existing forests, restoring degraded ecosystems, and integrating afforestation only as a complementary measure under strict safeguards. Justice, equity, and ecological integrity must remain central.

Conclusion: A Call for Real Solutions

The findings challenge a popular climate narrative: that we can plant our way out of the fossil fuel crisis. While trees are vital allies in mitigating climate change, they cannot offset the immense carbon debt embedded in fossil fuel reserves.

Instead, the path forward requires bold policy shifts: reducing fossil fuel extraction, scaling renewable energy, and addressing systemic reliance on carbon-intensive economies. Planting trees should support these strategies, not replace them.

As the authors conclude, “Afforestation can complement climate mitigation, but it cannot substitute for cutting fossil fuel emissions at the source.”

DOI: https://doi.org/10.1038/s43247-025-02394-y

Topics of interest

Climate