Flying in formation

How to combine hydrogen and carbon capture

READERS OF The Economist are a well-travelled lot. Many of them will be aware, perhaps slightly guiltily, that one of the biggest personal contributions to climate change is all that jet-setting. On average, each person on Earth going about their normal business produces the equivalent of five tonnes of CO2 a year. But a single transatlantic round trip produces the equivalent of about one tonne per passenger even in economy class.

For some, the problem with global warming is the idea that they may have to change their behaviour to fight it, not just by recycling or eating more seasonal food but by, heaven forbid, forgoing that holiday in Gstaad or the Maldives. Eventually zero-carbon technology may be able to avert some of those difficult sacrifices, by combining green-hydrogen production with a way of sucking CO2 out of the atmosphere to make synthetic fuels. This is currently very expensive, but it could help low-carbon aviation to take off.

On current trends, air-passenger numbers are expected to double within the next 20 years, mostly because of growth in Asia. That could push up today’s emissions of 1bn tonnes of…