The Politics and Science of Jet Fuel

If you’ve flown recently, you might have seen a pre-takeoff promotional video about the airline’s commitment to sustainability. One airline has even suggested that its planes will soon be powered by fruit compost.

Meantime, airline lobbyists in Washington are trying to weaken environmental safeguards in ways that would increase pollution and waste taxpayer money. Not all sustainable aviation fuels are created equal. Some, such as high-quality e-fuels and fuels sourced from cooking oil, could significantly reduce the climate impact of the 25,000 daily flights across the U.S. Others, like those based on sugarcane, could cause deforestation and harm the climate. As officials decide which fuels will qualify for tax credits under the Inflation Reduction Act, it’s critical to get this assessment right.

The global aviation industry is one of the largest sources of climate pollution. If its emissions were measured alongside countries, it would be the sixth-largest. For the existing fleet, and tens of thousands of new planes slated to enter markets over the next two decades, an aviation tax credit focused on truly sustainable fuels would spur greener private-sector innovation and lead to cleaner and more efficient air travel.

But fuels that are derived from natural resources aren’t always good for the climate. Depending on their production process and feedstocks, those fuels can cause deforestation, increase pollution and raise food prices.

Federal regulators should preserve rigorous environmental standards such as those set by the International Civil Aviation Organization to determine the extent to which different sustainable fuels reduce climate pollution in production and use. We need to make room for promising new technologies like synthetic e-fuels made from surplus renewable electricity and direct air capture of carbon.

Washington is right to recognize that incentives for private innovation should be the leading path toward a cleaner, thriving aviation industry. Calls by some in Europe to limit flights are impractical here, and the U.S. airlines’ push to grant tax credits to lower integrity fuels would cause environmental damage and crowd out cleaner, innovative fuels.

For an example of smart policies, look to Washington state, where tax incentives to promote the alternative-fuel industry have taken shape. In May, a Dutch company chose the state as the future home for its new biogas plant, which is set to produce 30 million gallons of sustainable aviation fuel a year starting in 2028. Last month a U.S. startup also broke ground on a Washington plant to make fuel from carbon dioxide, water and renewable power.

The stakes are high. For the sake of a stable climate and efficient use of federal money, let’s not let politics get in the way of science.

Mr. Krupp is president of the Environmental Defense Fund.