The big downside to biofuels: land-use change that can erase climate gains

A major downside to biofuels is that large-scale production often drives land-use change—clearing forests or diverting cropland—which can negate their climate benefits while increasing food prices and harming biodiversity. Biofuels can help decarbonize hard-to-electrify sectors, but when they expand into high-carbon or food-producing landscapes, their overall environmental footprint can become worse than the fossil fuels they aim to replace.

Why biofuels seemed like a climate win—and where the problem appears

Biofuels, such as ethanol and biodiesel, are made from plant matter or waste and were promoted to cut tailpipe emissions and oil dependence. Plants absorb CO2 as they grow, so in theory burning biofuels recycles carbon already in the biosphere. The catch is in how and where the feedstocks are grown. If forests, peatlands, or grasslands are converted to produce energy crops—or food crops are diverted to fuel, prompting expansion elsewhere—the resulting “land-use change” can release large carbon stocks and increase agricultural pressure worldwide.

How land-use change undermines climate gains

Direct vs. indirect land-use change

Direct land-use change happens when land is converted specifically for biofuel feedstock, while indirect land-use change (ILUC) arises when existing cropland is diverted to biofuels and food production shifts into new areas, potentially causing deforestation or habitat loss elsewhere. Both can add large, long-lived carbon emissions that overwhelm the tailpipe savings of biofuels.

The following points summarize the mechanisms by which land-use change can turn biofuels into a net climate and environmental liability.

• Carbon debt from conversion: Clearing forests, draining peat, or plowing grasslands releases decades’ worth of stored carbon, creating a “carbon debt” that many biofuel systems may take years or decades to repay—if ever.
• Food vs. fuel pressure: Diverting maize, sugar, soy, or vegetable oils to fuel reduces supplies for food and feed, pushing up prices and incentivizing cropland expansion elsewhere.
• Biodiversity loss: Monoculture expansion into high-value habitats reduces species richness and fragments ecosystems, particularly in tropical regions.
• Nitrous oxide and fertilizer use: Increased fertilizer to boost yields emits nitrous oxide, a potent greenhouse gas, and can degrade water quality.
• Water stress: Irrigated feedstocks can exacerbate freshwater scarcity in already stressed basins.
• Long payback times: Even “moderate” land-use emissions can take many years to amortize, delaying climate benefits beyond near-term decarbonization targets.

Taken together, these pathways mean a biofuel can look clean at the tailpipe but still carry a high lifecycle carbon intensity once land-use and supply-chain effects are included.

Evidence and real-world impacts

Research over the past decade has examined whether the climate promise of biofuels holds up after accounting for land and market dynamics. Results vary by feedstock and region, but several findings stand out.

The examples below illustrate how policy, markets, and land systems interact to shape biofuel outcomes.

• U.S. corn ethanol: A 2022 peer-reviewed analysis (PNAS) found that, when land-use change and fertilizer responses were included, U.S. corn ethanol’s lifecycle emissions were likely no lower—and potentially higher—than gasoline over the study period, a conclusion debated by industry and some academics.
• EU policy on high ILUC-risk oils: The European Union classifies palm oil as high ILUC-risk and is phasing down its use in biodiesel toward 2030, with tighter sustainability criteria under the latest Renewable Energy Directive (RED III). Some member states have moved faster.
• Tropical deforestation links: Rapid palm expansion in Southeast Asia historically contributed to forest and peatland loss. While deforestation rates have fallen in Indonesia in recent years, continued demand for palm-based biodiesel keeps pressure on landscapes unless strong safeguards are enforced.
• Food price spikes: Economists identify biofuel mandates as one factor—alongside weather shocks, trade restrictions, and conflict—in the 2007–08 food price spike and as an added pressure during the 2022 commodity shock.
• Regional contrasts: Sugarcane ethanol in Brazil can achieve relatively low carbon intensity when grown on existing pasture with strict safeguards, but expansion into the Cerrado or sensitive biomes can erode benefits and biodiversity.

The lesson is not that all biofuels are bad, but that outcomes depend heavily on feedstock choice, land-use context, and policy design. Without stringent safeguards, ILUC can overwhelm intended emissions reductions.

Other notable downsides beyond land

While land-use change is the most consequential risk, other trade-offs merit attention.

These additional issues show up across different biofuel pathways and affect communities and air quality.

• Air pollutants: Some blends can increase certain pollutants (e.g., acetaldehyde for ethanol; NOx in some biodiesel use cases) even as they reduce others, complicating urban air-quality goals.
• Supply-chain fraud and traceability: Limited supplies of truly waste-derived oils (like used cooking oil) create incentives for mislabeling or imports linked to deforestation without robust verification.
• Scalability limits: Truly low-ILUC feedstocks (wastes, residues) are finite, constraining how much “good” biofuel can displace fossil fuels economy-wide.

These factors reinforce that biofuels are not a one-size-fits-all climate solution, particularly for sectors where electrification is more efficient.

Can the risks be reduced?

Policymakers and industry can materially lower biofuel downsides by focusing on feedstocks and practices that minimize land pressure and by improving oversight.

The following measures represent the most widely supported ways to reduce ILUC risk and environmental harm.

1. Prioritize wastes and residues: Favor used cooking oil, tallow, agricultural residues, and municipal/woody wastes over food-grade oils and staple crops.
2. Cap or phase down high ILUC-risk feedstocks: Limit or end incentives for palm and soy biodiesel unless verified low-ILUC pathways are demonstrated.
3. Protect high-carbon and high-biodiversity lands: Enforce no-conversion rules for forests, peatlands, and native grasslands, with satellite monitoring and strong penalties.
4. Use robust lifecycle accounting: Include ILUC, fertilizer emissions, and supply-chain impacts in carbon intensity scoring; update models with real-world land data.
5. Strengthen traceability: Require chain-of-custody documentation and third-party audits to reduce fraud in “waste” feedstocks.
6. Target hard-to-electrify uses: Reserve limited sustainable biofuels for aviation, maritime, and some heavy-duty applications, while electrifying cars and light trucks.
7. Boost yields without expansion: Support sustainable intensification on existing farmland and restoration of degraded land to avoid new conversion.

Implemented together, these steps can retain biofuels’ role where they are most valuable while avoiding the worst land-use outcomes.

What about advanced biofuels and sustainable aviation fuel (SAF)?

Advanced biofuels—made from cellulosic materials, residues, or municipal solid waste—and several SAF pathways can achieve much lower ILUC risk and carbon intensity. HEFA-based SAF from genuine waste oils, Fischer–Tropsch fuels from biomass residues, and alcohol-to-jet from non-food feedstocks are promising. However, near-term supply is constrained by feedstock availability and capital costs, and robust verification is essential to ensure waste streams are not backfilled by high ILUC-risk oils.

Bottom line

Biofuels can help decarbonize parts of transport, but a big downside is their tendency to trigger land-use change that undermines climate goals and harms food security and nature. The safest course is to prioritize waste- and residue-based fuels, apply strict land safeguards and lifecycle accounting, and deploy biofuels where alternatives are hardest—while accelerating electrification elsewhere.

Summary

The principal downside of biofuels is land-use change: converting or displacing cropland and natural ecosystems can release large carbon stores, raise food prices, and damage biodiversity, often canceling the intended climate benefits. Evidence from the U.S., EU, and tropical regions shows that feedstock choice and policy design are decisive. Steering incentives toward wastes and residues, tightening sustainability standards, and reserving biofuels for hard-to-electrify uses can mitigate these risks but do not eliminate the fundamental constraints on scalable, low-impact biofuel supply.

What are 5 disadvantages of biodiesel?

Cons of Biodiesel:

• Tailpipe Emissions. Assets that run on biodiesel still have tailpipe emissions.
• Can be More Expensive. The cost of biodiesel depends on the blend level and the feedstocks.
• Gels in Cold Weather. Higher blends of biodiesel gel in the engine in cold weather.
• Not Available Everywhere.

Why don’t we use biofuel?

Biofuels cost more to produce than fossil fuel. They tend to consume more resources and energy to produce. Many divert water and land from food production and some consume more energy than they yield.

Is biofuel bad for your health?

In addition to spewing climate-warming emissions, biofuels also pollute our air. Burning these fuels produces tiny toxic particles, ozone, and nitrogen dioxide. All three can severely irritate respiratory systems, triggering asthma attacks.

What are the negatives of biofuels?

Disadvantages of biofuels include deforestation, loss of biodiversity, increased food prices and potential food shortages, significant land and water requirements, high production costs, and the release of air pollutants like nitrogen oxides and fine particles that negatively impact public health and contribute to smog. Furthermore, the energy required for biofuel production and transport can be substantial, sometimes even exceeding the energy content of the fuel itself, and the quality and efficiency of these fuels can vary. 
Environmental & Land Use Concerns

• Deforestation and Habitat Loss: Opens in new tabGrowing crops for biofuels requires large amounts of land, which can lead to deforestation and destruction of natural habitats, reducing biodiversity. 
• Water Consumption: Opens in new tabBiofuel crop production often demands substantial water resources for irrigation, potentially straining local water supplies and disrupting ecosystems. 
• Soil Erosion: Opens in new tabLarge-scale monoculture farming for biofuels can lead to soil erosion and degradation. 
• Air Pollution: Opens in new tabBurning biofuels releases air pollutants, including fine particulate matter, ozone, and nitrogen dioxide, which can trigger respiratory problems, heart attacks, and contribute to smog. 

Socioeconomic Impacts

• Food Prices and Shortages: Opens in new tabUsing land to grow biofuel crops reduces the amount of land available for food production, which can drive up food prices and potentially lead to food shortages. 
• High Production Costs: Opens in new tabSignificant investments in infrastructure and technology are needed to produce biofuels, making them more expensive than traditional fossil fuels. 

Energy and Production Issues

• Production Energy Use: The process of producing, transporting, and refining biofuels can consume a large amount of energy, sometimes to the point where the energy input is not significantly less than the energy output. 
• Variable Quality and Efficiency: The quality of biofuels can vary depending on the feedstock and production process. Additionally, some biofuels are less efficient than other fuels, releasing more heat and less usable energy. 
• Technical Challenges: High-ethanol biofuels may require modifications to car engines, and higher blends of biodiesel can gel in cold weather, limiting their use.