Two events have got me thinking a lot more about veganism recently; the publication of that UN report reminding us that meat production and consumption is a major contributor to the catastrophic impact of climate change, and an item on the quiz show QI saying that a lot of fruit and veg isn’t truly vegan, apparently because its current cultivation methods exploit bees.

A friend on social media made the powerful point that, even if you accept QI’s premise, eating an avocado is still a lot more morally defensible than eating a bacon sandwich.

This is a powerful argument against those nitpicking attacks on veganism, and indeed environmentalism, which use any minor anomaly to try and discredit the overall philosophy.

Eating even a bee-exploiting avocado doesn’t discredit your veganism. Really there’s a sliding scale for ethical consumption which has foie gras at the bottom and naturally pollinated roots and berries at the top.

Just because you’re not right at the top doesn’t mean you should chuck it all in and start ordering the milk-fed veal.

I believe the argument also resonates with the UN report and the basic dilemma I think it presents, not only for the vegan movement but for all of us.

The UN report gives a compelling environmental argument that we need drastically to reduce meat production, ideally to zero, to help stave off the worst impacts of climate change.

Some commentators have aligned this to the ethical argument that exploiting animals is morally wrong, but I believe the two arguments are very different, and actually conflict with each other.

True, the environmental argument does lead to the removal of human exploitation of animals for meat, but only as a by-product of removing the animals themselves.

There are over a billion beef cattle in the world, and around a billion each of sheep, pigs and chickens. We need a massive reduction in animal methane production and a mass re-purposing of animal grazing for sustainable human food production.

The only way I can see to achieve this is to reduce the populations of these species to close to extinction levels.

Moving the world’s population to a plant-based diet can’t happen overnight. It requires a vast coordinated global effort to ramp up sustainable cultivation of food for humans, and at the same time winding down cultivation of crops for meat production.

If everyone gave up meat tomorrow, all the environmental impacts of meat production would still exist, and I suspect our capacity for providing plant-based alternatives would struggle to keep up with the demand.

But if some of us give up or cut down, it’s at least a start. There are enough dedicated carnivores in the world to take up the slack as more and more of us move to more sustainable and ethical alternatives, from flexitarianism to ‘strict’ veganism (with or without avocados).

As more of us change, it paves the way for the fundamental changes the human race has to make in what and how we consume. It’s not ethically perfect, but it’s much better than carrying on as we are.

But it doesn’t remove the dilemma of what happens to the livestock, and I don’t have an easy answer.

Sadly, unlike with the abolition of human slavery, we can’t just set our animal slaves free, because we can’t afford to keep feeding them and save the planet at the same time.

There’s an extreme argument, which I have some sympathy with, that it’s payback time, and that humanity should just be allowed to die out, let the other animals get on with it and the Earth restore its natural balance.

Even this, though, wouldn’t provide a positive solution for the species we’ve historically exploited, because they have come to rely on us for their survival.

While it’s pleasing in a way to think of a planet where all the farmed animals escape back to the wild, freed from the tyranny of their extinct human masters, in reality most of them would die out pretty quickly without humanity.

Ultimately, I think we have to take this opportunity to reshape our whole relationship with the animal kingdom, just as the digital revolution is making us re-evaluate our relationship with work.

We need to end humanity’s abuse of the animal species we have domesticated, and we need to find a way to do this which enables those species to survive.

I was going to wax sentimental and say that it would be a shame, if I end up having a great grand-daughter, that her only experience of cows, sheep, chickens, pigs, goats, alpacas and so on may be seeing them in a zoo. Then I remembered that zoos are a form of animal exploitation, so she probably wouldn’t even have that.

A partial answer may be to retain some of the less barbaric things humanity does with animals, and remove the cruelty as far as we possibly can.

Keep cows for milk, chickens for eggs, sheep and goats for milk and wool, horses for riding and pigs as pets (I understand they make good ones), whilst forbidding any farming method which could reasonably be expected to cause the animal pain or distress.

I know it’s far from ideal. Practically, we would still only be able to maintain a fraction of the populations which we currently kill for meat, and there’s a big question whether anyone would be able to afford to buy an egg, once we’ve take away the economies of scale of mass production.

And ethically, we would still be exploiting animals.

Yet it would mean mitigating what for me is the greatest act of barbarism, which is to exploit these species for millennia then exterminate them when that exploitation starts to threaten our own survival. It would retain what I hope are the positive elements of humanity’s working relationship with animals, and it would be a lot more defensible, morally and environmentally, than carrying on eating bacon sandwiches.

It’s not the best answer, whether your a committed meat-eater or a committed vegan, but given the alternatives it may be the least worst, for the chickens and for us.