Shagun: Through the protagonist of your book, Tim Searchinger, you argue that crop-based ethanol can be twice as harmful to the climate as petrol as it drives land-use change. Yet governments worldwide seem to be doubling down on ethanol. Promotion of sugar- and grain-based ethanol in India mirrors the growing use of corn-based ethanol in the US. Are these policies grounded in scientific evidence or influenced by farm lobbies?
Michael Grunwald (MG): The emissions math for biofuels is actually less favourable in countries such as India, where agricultural yields are low. And hence, biofuel policy there is moving in the wrong direction. Europe has somewhat moved to the right approach, but it is still not perfect. As I describe in the book, the EU’s initial Renewable Energy Directive had a mandate that 10 per cent of transport fuel should come from biofuels. The target remained in place even after science showed that land-use changes could negate many climate benefits of crop-based biofuels. This is because of political reasons. Only when electric vehicles emerged as an attractive alternative did Europe cap the use of crop-based biofuels. It has also stated that it will not allow crop-based biofuels to qualify as sustainable aviation fuel. In the US, on the other hand, President Donald Trump’s “one big beautiful bill” in 2025 cut off almost all subsidies for renewables, except for biofuels, and stated that emissions due to land-use change cannot be used when calculating emissions for biofuels.
Shagun: How would you assess the prospects of second generation (2G), or cellulosic, ethanol and other sustainable alternatives to conventional fossil fuels?
MG: They do not really work. Airlines often fly a single aircraft on recycled cooking oil and present it as the future of sustainable aviation fuel. But they are not going to run their entire fleets on cooking oil; the feedstocks are more likely to be crops such as corn and soya beans. At one point, advocates claimed that cellulosic ethanol would supply 30 billion gallons [over 113 billon litres] of fuel a year in the US by 2025. That has not happened. So far, 2G biofuels have been a disappointment. Instead, soya bean-based biodiesel is now considered as a next generation or an advanced biofuel in the US. Had cellulosic ethanol proved commercially viable, vast areas of farmland would by now likely have been devoted to growing crops such as jatropha or switchgrass. That has probably been a blessing for the planet as growing these crops would have led to large-scale deforestation and wetland destruction.
Shagun: Your book does elaborate on this point and contends that the real environmental villain is the expansion of farmland into natural ecosystems. One of its proposed solutions is to increase yields on existing farmland. But that seems paradoxical at a time when industrial farming is under criticism for its heavy reliance on chemical fertilisers, which then damage ecosystems. How do you reconcile those two arguments?
MG: I am making a case for high-yield agriculture, not necessarily for industrial agriculture. There is a widespread view that the environmental tragedy of farming is intensification. I do not dismiss that concern. Factory farms often handle manure poorly, leading to pollution of rivers and lakes. Intensification can certainly create environmental problems. But the greater environmental tragedy is what I would call “extensification”—the expansion of agriculture into natural ecosystems. The real problem is not the transformation of a picturesque, low-yield farm into a more intensive one…
This interview was originally published in the July 1-15, 2026 print edition of Down To Earth