I think this should be the perspective through which we start to see everything. This is the greatest crisis humanity has ever faced: the breakdown of our life-support systems. The Governments that will be judged favourably by future generations are those that put that issue front and centre. Other things are subsidiary to our survival. It is imperative that we should start favouring a low-carbon diet and use public policy to disfavour a high-carbon diet. Whether through farm subsidies—I think that does play a role—or meat taxes, which I think could also play a role, we should find all the instruments possible to steer and encourage people to reduce the environmental impacts of their diets.
The most important metric here is what scientists call carbon opportunity costs, which is basically, “What could you be doing on that land if you weren’t doing this?” If, for instance, you are producing beef or lamb on this piece of land, what is the carbon opportunity cost of that? What would be the carbon storage if, instead, trees and wild habitats were allowed to return? There has been some new research just published, or a new compilation of research, on Our World in Data showing that when you look at the carbon opportunity costs, those of beef and lamb are massively greater than those of anything else we eat. It is really, really huge. Even when you take food miles into account, they are tiny by comparison to those carbon costs, and that is what we should focus on.