Biofuels’ Environmental Downsides: What the Evidence Shows in 2025

Biofuels can harm the environment by driving deforestation and land-use change, increasing greenhouse gas emissions through soil carbon losses and fertilizer use, degrading biodiversity, straining and polluting water resources, worsening certain air pollutants, and depleting soils; the severity depends on the feedstock, where it is grown, and how it is produced and used. Researchers and agencies such as the IPCC and the International Council on Clean Transportation (ICCT) agree that some biofuels—especially those made from food crops and linked to land expansion—can have net climate and ecological costs that outweigh benefits when full supply chains are considered.

How biofuels can harm the environment

The negative effects of biofuels vary widely by crop (e.g., corn, sugarcane, soy, palm), geography, and farming practices, but a consistent set of risks emerges from peer‑reviewed studies and regulatory assessments. The points below summarize the main environmental harms identified across the literature and recent policy reviews.

• Land‑use change and deforestation: Converting forests, savannas, and peatlands to produce biofuel feedstocks releases large stores of carbon and fragments habitats. Indirect land‑use change (ILUC) can occur when expanding biofuel production displaces food crops or cattle into new frontiers. Analyses show that biodiesel from palm oil grown on drained peat or linked to tropical forest loss can have a carbon footprint well above fossil diesel on a per‑energy basis, and soy biodiesel can also be high when Cerrado or forest conversion is included.
• Uncertain or negative greenhouse gas balance: While biofuels can reduce tailpipe CO2, total lifecycle emissions can rise if soil carbon declines, if energy‑intensive inputs are used, or if ILUC occurs. Nitrous oxide (N2O) from nitrogen fertilizers—about 273 times more potent than CO2 over 100 years—can erode or eliminate climate benefits for high‑input crops like corn and rapeseed. In some scenarios, first‑generation biofuels approach or exceed the carbon intensity of the fossil fuels they replace.
• Biodiversity loss and ecosystem disruption: Large‑scale monocultures reduce habitat complexity and can harm pollinators and other wildlife. Palm oil expansion in Southeast Asia has been closely tied to the loss of orangutan and other endemic species’ habitat, especially on peatlands and in remaining lowland forests. Pesticides and herbicides add further pressure on ecosystems.
• Water use and contamination: Irrigation for biofuel crops can heighten water stress in arid basins; even where rain‑fed, intensive cultivation can alter local hydrology. Nutrient runoff (nitrogen and phosphorus) from fertilizer use contributes to algal blooms and hypoxic “dead zones,” such as those observed seasonally in the U.S. Gulf of Mexico, while processing plants generate wastewater that must be treated to avoid local pollution.
• Air pollution and public health impacts: Ethanol blends typically cut tailpipe carbon monoxide and some particulates but can increase emissions of acetaldehyde and other ozone‑forming compounds. Biodiesel often lowers particulate and carbon monoxide but has been shown to raise nitrogen oxides (NOx) in certain engines and duty cycles, which can worsen urban smog. Open burning of residues (e.g., pre‑harvest sugarcane burning) and peat/savanna fires associated with land conversion create severe regional haze episodes.
• Soil degradation and erosion: Intensive cultivation and excessive removal of residues for cellulosic fuels can reduce soil organic carbon, increase erosion, and impair long‑term fertility. Heavy machinery compaction and limited crop rotations further degrade soil health.
• Fire risk and transboundary haze: Draining peatlands for oil‑palm plantations greatly increases fire susceptibility; during dry seasons, peat fires can smolder for weeks, sending particulate‑laden smoke across national borders and causing major health and climate damages.
• Waste‑feedstock constraints and indirect effects: Truly low‑impact feedstocks like used cooking oil (UCO) and animal fats are limited. Rapid growth in demand can trigger imports and the diversion of co‑products (e.g., palm fatty acid distillates), indirectly stimulating primary vegetable oil production and associated land‑use pressures elsewhere.
• Food‑fuel‑land tension: When cropland shifts from food to fuel, agricultural expansion often pushes into high‑carbon or biodiverse areas. This competition can amplify global environmental pressure even if the biofuel itself is produced efficiently.

Taken together, these risks are most acute for first‑generation, food‑based biofuels made from vegetable oils, sugar, and starch—particularly when production expands into forests, peat, wetlands, or species‑rich grasslands. Lifecycle accounting that includes ILUC is decisive: it often turns nominal climate gains into net losses.

When and where impacts are worst

Hotspots include: oil‑palm expansion on peat and forest margins in Southeast Asia; soy expansion into Brazil’s Cerrado and parts of the Amazon arc of deforestation; high‑input corn ethanol in regions with intensive fertilizer use and nitrate‑laden runoff; and irrigated biofuel crops in already‑stressed watersheds. In these contexts, net greenhouse gas emissions can exceed those of fossil fuels for years or decades, and local air and water quality can suffer markedly.

Nuance: not all biofuels are equally harmful

Advanced or “waste‑based” pathways—such as fuels from used cooking oil, municipal solid waste, manure, or genuinely residual forestry/agricultural biomass—tend to have lower impacts when robust safeguards are enforced. Perennial energy crops (e.g., miscanthus, switchgrass) grown on degraded land can build soil carbon and reduce erosion, though benefits depend on site conditions and fertilizer management. Even so, leakage risks, methane control (for biogas), and over‑harvesting of residues remain material concerns.

The following practices are widely cited by scientists and regulators as ways to reduce environmental harm from biofuels:

• Avoid high‑carbon and high‑biodiversity lands: No conversion of forests, peatlands, wetlands, or species‑rich grasslands; protect riparian buffers and corridors.
• Prioritize wastes and true residues: Use feedstocks that do not require dedicated land or that would otherwise decompose and emit methane, while leaving enough residue to maintain soil health.
• Account for ILUC and full lifecycle emissions: Use conservative carbon accounting and cap or phase down high‑ILUC‑risk feedstocks.
• Manage nitrogen and soils carefully: Optimize fertilizer through precision application, cover crops, and perennials to curb N2O and runoff; limit residue removal to protect soil organic carbon.
• Safeguard water: Avoid expansion in water‑stressed basins; implement runoff controls and robust wastewater treatment at plants.
• Control air emissions: Phase out open burning, use modern engine/after‑treatment technologies, and monitor aldehydes and NOx.
• Strengthen certification and traceability: Independent auditing to prevent fraud and displacement, with enforceable penalties.

These measures can materially shrink impacts, but they rely on rigorous implementation and enforcement; without that, environmental externalities tend to reappear elsewhere in the system.

The policy landscape in 2025

Regulators are tightening sustainability rules while demand for low‑carbon fuels grows. The European Union’s updated Renewable Energy Directive (RED III, adopted 2023) raises transport renewable targets, strengthens advanced biofuel sub‑targets, and continues the phase‑out of high ILUC‑risk feedstocks such as palm oil by 2030 under existing delegated acts. The United States Renewable Fuel Standard sets volumetric mandates but faces ongoing debate over lifecycle modeling, land‑use impacts, and biomass‑based diesel growth. California’s Low Carbon Fuel Standard and similar policies in other jurisdictions assign carbon‑intensity scores that increasingly reflect soil carbon, N2O, and ILUC. Aviation demand for sustainable aviation fuel (SAF) is rising under schemes like ICAO’s CORSIA, intensifying scrutiny of vegetable‑oil‑derived fuels and pushing a shift toward waste‑ and residue‑based pathways.

Bottom line

Biofuels are not inherently “green.” When they expand cropland into carbon‑rich or biodiverse landscapes, rely on heavy fertilizer inputs, or draw on scarce water, their climate and ecological toll can exceed that of the fossil fuels they replace. The least harmful options are waste‑ and residue‑based fuels and carefully sited perennials with strong safeguards. Without stringent accounting and governance, however, biofuel programs risk exporting environmental damage from the tailpipe to the land, water, and atmosphere.

Summary

Negative environmental effects of biofuels include land‑use change and deforestation, high lifecycle greenhouse gas emissions (via soil carbon loss, ILUC, and fertilizer‑driven N2O), biodiversity decline, heavy water use and nutrient pollution, specific air‑quality drawbacks (NOx and aldehydes), soil degradation, and heightened fire risk. These harms are most pronounced for first‑generation, food‑based biofuels produced in sensitive regions. Effective mitigation hinges on prioritizing waste/residue feedstocks, protecting high‑carbon and high‑biodiversity lands, managing nitrogen and water carefully, and enforcing rigorous, ILUC‑aware sustainability standards.

How does biofuel negatively affect the environment?

Biofuels harm the environment through factors including: significant land use changes and deforestation, which create a “carbon debt” and impact biodiversity; heavy use of fertilizers and pesticides, which pollute water and contribute to emissions of the potent greenhouse gas nitrous oxide; release of hazardous air pollutants and ground-level ozone during production and combustion; and potential negative impacts on water resources due to irrigation and pollution from processing.
 
Land Use and Deforestation 

• “Carbon Debt”: Opens in new tabCreating farmland for biofuel crops, especially by clearing forests, releases stored carbon into the atmosphere, creating a “carbon debt”. The carbon released may not be recovered by the biofuel for decades, if ever, making some biofuels worse than fossil fuels. 
• Biodiversity Loss: Opens in new tabLarge-scale cultivation of biofuel crops replaces natural habitats like forests and prairies, leading to a loss of biodiversity and threatening endangered species. 

Pollution and Greenhouse Gas Emissions 

• Fertilizer Use: Opens in new tabGrowing biofuel crops requires substantial amounts of fertilizers. Excess fertilizer runs off into waterways, contaminating ground and surface water and increasing eutrophication. 
• Nitrous Oxide (N₂O) Emissions: Opens in new tabMicrobial action converts excess nitrogen fertilizer into N₂O, a greenhouse gas almost 300 times more potent than carbon dioxide in trapping heat. 
• Pesticide Use: Opens in new tabThe large-scale use of pesticides in biofuel crop cultivation pollutes critical habitats and can lead to toxic algal blooms. 
• Hazardous Air Pollutants: Opens in new tabBiofuel manufacturing plants can release high levels of hazardous air pollutants, sometimes comparable to oil refineries, which negatively affect air quality and human health. 
• Ground-level Ozone: Opens in new tabThe production and combustion of biofuels can lead to increased ground-level ozone and smog, which are harmful to respiratory health. 

Water Resources

• Water Consumption: Opens in new tabThe cultivation of many biofuel crops, such as maize and sugar cane, requires significant amounts of water, and large-scale production can strain water resources, particularly in water-scarce regions. 
• Water Quality: Opens in new tabRunoff from fields treated with fertilizers and pesticides pollutes both surface and groundwater. 

Indirect Land Use Change (ILUC) 

• Demand for biofuel crops can drive expansion into new agricultural areas, potentially leading to the conversion of natural or non-food lands for food production or other purposes, creating indirect land use changes and additional environmental impacts.

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.

What are 5 disadvantages of biofuel?

What are 6 disadvantages of biofuel?

• Biofuels, derived from organic matter like plant materials and animal waste, offer a promising avenue for renewable energy.
• Land Use Issues.
• High Cost.
• Food Security.
• Energy Intensive Production.
• Limited Availability.
• Greenhouse Gas Emissions.

Is biofuel eco friendly or not?

Biofuels shall significantly reduce greenhouse gas emissions as compared to fossil fuels. The principle seeks to establish a standard methodology for comparing greenhouse gases (GHG) benefits. Biofuel production shall not violate human rights or labor rights, and shall ensure decent work and the well-being of workers.