Biofuels Likely to Emit More CO2 Than Fossil Fuels

The requirement for modern biofuels is anticipated to witness significant growth to reduce climate emissions. They are, however, far from being a climate-neutral substitute for gasoline and diesel.

According to recent research published in Nature Climate Change, CO₂ emission factors for biofuels may exceed those for fossil diesel burning under present land-use rules due to large-scale land removal associated with biomass production.

Before bioenergy can contribute effectively to carbon neutrality, international agreements must assure the effective conservation of forests and other natural lands through the implementation of carbon pricing, according to an expert team from the Potsdam Institute for Climate Impact Research (PIK).

Our results show: The state of current global land regulation is inadequate to control land-use-change emissions from modern biofuels. If cultivation for bioenergy grasses is not strictly limited to marginal or abandoned land, food production could shift and agricultural land use expand into natural land. This would cause substantial carbon dioxide emissions due to forest clearing in regions with weak or no land regulation.

Leon Merfort, Study Lead Author, Potsdam Institute for Climate Impact Research

These indirect effects of bioenergy use present policymakers with a challenge, as the food and bioenergy markets are internationally interconnected but beyond the control of individual national policies. Unfortunately, the regulatory gap in the land-use sector would keep bioenergy supplies low while forcing the energy sector to phase out fossil fuels even quicker to compensate for increased emissions from land-use change. This, in turn, raises the demand for bioenergy.

The scientists used energy and land system models to create alternate transformation pathways consistent with maintaining global warming well below 2 ºC. These routes involve varied assumptions on land-use and energy policies, which have a substantial impact on CO₂ emissions from land-use change as well as the quantity of bioenergy utilized to meet global energy demand.

By contrasting these circumstances with a corresponding counterfactual scenario with really no bioenergy production and thus lower land-use-change emissions, the investigators were able to extract emission factors, which ascribe CO₂ emissions from land-use change to bioenergy production in the light of various policy frameworks.

Putting a Price on Emissions From Land-Use Change to Achieve Climate Neutrality

We find that without additional land-use regulation, land clearing related to the production of modern biofuels results in CO₂ emission factors - averaged over a 30-year period - that are higher than those from burning fossil diesel. Our results show that a globally comprehensive land protection or carbon pricing scheme would avoid high CO₂ emissions from land-use change related to the production of modern biomass.

Florian Humpenöder, Study Co-Author, Potsdam Institute for Climate Impact Research

The results highlight the need for a paradigm shift in land-use policy.

Co-Author Nico Bauer notes, “Phasing out fossil fuels will generate demands of bioenergy worth hundreds of billions of Dollars by mid-century. The agricultural sector will try to take advantage of these new opportunities, but potential expansion into high-yield areas often coincides with high upfront CO₂ emissions from land conversion.”

“Only reducing the demand for bioenergy will not solve this problem. Surprisingly, we also find that the protection of 90% of all global forest areas is not enough because the remaining 10% would still be too big of a loophole,” Nico Bauer highlights.

The comprehensiveness of covering nearly 100% of all forests and other natural regions is more important than the price level itself. Pricing all emissions from land-use change with only 20% of the CO₂ price in the energy sector is more effective than a global forest preservation scheme covering 90% of all forests. As the phase-out of fossil fuels continues and rules in the land-use sector lag, the protection of carbon stored in existing forests should be prioritized on the international policy agenda.

Bauer concludes, “Our results show that bioenergy can be produced with limited emissions under effective land-use regulations. Yet, if the regulatory gap remains wide open, bioenergy will not be part of the solution to mitigate climate change, but part of the problem.”

Journal Reference:

Merfort, L., et al. (2023). Bioenergy-induced land-use-change emissions with sectorally fragmented policies. Nature Climate Change. doi.org/10.1038/s41558-023-01697-2.