The British Government currently mutters that all new cars must be electric in 2040. The Labour Party is making noises that this should be brought forward to 2030. This is not the way to deal with climate change:

Toyota is developing a hydrogen-powered car which could be fuelled for a year by the manure of a single cow, bosses have claimed.

Chief technology officer Shigeki Terashi said a cow's droppings can be converted to produce enough hydrogen to run its next-generation Mirai saloon for 12 months.

The concept car uses a “fuel stack” to transform liquefied hydrogen into electricity with water as the only byproduct, making the technology zero emission.

It’s a fuel cell, not a stack, even though cells come in stacks.

But the point is there are myriad technologies which could be used to meet whatever emissions target we might have. Choosing one of them, now, when the varied possibilities are not mature, is the incorrect decision.

We would point out that one of us has actually worked on fuel cells and they’re lovely things - even if they may or may not be the correct replacement for the internal combustion engine.

A bureaucratic - or political - decision to choose the one technology now is that wrong decision. The correct method is to set the performance target, whatever it is, then leave markets to tell us which meets that target best. The problem being not the choosing of the one technology, but the ruling out of all the others, some of which may well be better.

This stuff is complicated, meaning we’ve got to turn to that only complex calculating engine we’ve got, the economy as a whole and its price system.