Ahead of the UN Climate Change Conference COP30, which opens next week in Belém, Brazil, nearly 100 members of the global scientific community, including representatives from the Union of Concerned Scientists, have signed on to a letter calling on global leaders to limit a ‘dangerous expansion” of biofuels.

The letter comes as Brazil seeks high-level support for a leaders’ pledge to quadruple so-called “sustainable fuel” use—including a doubling of biofuels consumption—as a major component of the international community’s response to the climate crisis.