As world leaders prepare for COP30 in Belém, Brazil, nearly 100 leading scientists and environmental experts are urging negotiators to rethink the global drive toward expanded biofuel use.
In an open letter signed by members of the Union of Concerned Scientists and other international research bodies, the authors caution that current biofuel strategies risk deepening the climate crisis rather than mitigating it.
The intervention comes as Brazil pushes for a leaders’ pledge to quadruple so-called “sustainable fuel” use, including a doubling of biofuels consumption by 2035. The proposal, framed as a climate solution, is part of the country’s effort to position itself at the center of global energy diplomacy. But data from recent life-cycle analyses suggest that biofuels, on average, emit 16% more greenhouse gases than the fossil fuels they replace when land-use change, fertilizer production, and combustion are factored in.
By 2030, researchers estimate that expanded biofuel use could release an additional 70 million metric tons of CO₂ equivalent per year, roughly equal to adding 30 million new diesel vehicles to global roads. The figures expose a critical contradiction at the heart of current energy transition policies: what appears renewable on paper may, in practice, deepen dependence on carbon-intensive agricultural systems.
Beyond the emissions profile, scientists warn of cascading ecological and social effects. Scaling up biofuel feedstock production—often from crops like sugarcane, soy, or palm—risks accelerating deforestation and biodiversity loss in regions already under severe pressure, including the Amazon and Southeast Asia. Increased land conversion for energy crops also intensifies competition for water, contributes to agricultural runoff, and exacerbates food insecurity through higher commodity prices and volatility.
The letter notes that governments have previously recognized these risks. In 2020, the European Union capped first-generation, crop-based biofuels at 7% of transport energy to prevent further land-use impacts. Yet, with major economies now rebranding biofuels as “sustainable aviation fuel” or “renewable diesel,” the global market is again drifting toward large-scale expansion—this time under the banner of climate action.
Non-governmental organizations in producer nations such as Brazil and Indonesia are calling for more integrated governance frameworks that include cultivation limits, transparency in supply chains, and community-based oversight to manage local impacts. Such measures, however, remain largely voluntary and fragmented.
“The evidence is clear, burning crops for fuel is a bad idea. We can’t ignore the effects they have on the climate, ecology and food security. Governments must turn to truly sustainable alternatives rather than pushing solutions that, in many cases, do more harm than good,” said Cian Delaney, biofuels campaigner at Transport & Environment (T&E).
