It would be ironic if, in the end, it was lawyers who saved the world while I was out, tree-hugging and tweeting

This week I farewell my day job, my life’s work, and the law. A colleague, one of my bosses, came to say goodbye. He paced, and looked at the floor; I knew something weighty was on his mind.

“You can have too many lawyers,” he said. “I think it’s marvellous, what you’re doing. There are many, many people in this world who do more useful things than lawyers …”: this from a man who has spent his life law-making.

He might yet get the last laugh. It would be ironic if, in the end, it was lawyers who saved the world while I was out, tree-hugging and tweeting.

Rumbles from the Security Council and UN Secretary-General Ban Ki-Moon, on climate change and its threat to world peace and security, is a post for another day. This one’s about rights for nature, and the crime of ecocide.

In the end, environmental damage threatens basic human rights, which are all about civil society. Since we won’t have a society if we destroy the environment, there is, so the argument goes, no sense in calling one fundamental, while ignoring the other.

You could put it, as has the UN, in terms of sustainability, the rights of next generations. The more revolutionary concept -- not about us, or environment’s value to us -- is that of enforceable rights for Mother Nature in her own right, as written into the constitutions of Bolivia and Ecuador (where she is called ‘Pachamama’).

Bolivia, in April, established 11 new nature rights, including: the right to life and to exist; the right to continue vital cycles and processes free from human alteration; the right to pure water and clean air; the right to balance; the right not to be polluted; the right to not have cellular structure modified or genetically altered; the right “to not be affected by mega-infrastructure and development projects that affect the balance of ecosystems and the local inhabitant communities”.

It was Bolivia, incidentally, that stood alone at the Cancun climate talks last December, arguing that the texts were not strong enough.

Ecuador, too, changed its constitution in 2008 to give nature “the right to exist, persist, maintain and regenerate its vital cycles, structure, functions and its processes in evolution”, and require the government to take “precaution and restriction measures in all the activities that can lead to the extinction of species, the destruction of the ecosystems or the permanent alteration of the natural cycles”.

Reportedly, this was “derided within Ecuador”: the responsibilities fall largely on the government, and the government needs to keep oil flowing to sustain the economy. This little extortion racket suggests that the sceptics were right.

However, after the Deepwater Horizon oil spill in the Gulf, environmental activists used it to file a test case against BP.

Next month or thereabouts, September 2-5 I'm told, Polly Higgins visits New Zealand. The Guardian calls her a “lawyer turned campaigner”.

Formerly a London barrister, she wants ecocide declared a fifth crime against peace by the UN, which could be tried at the International Criminal Court, alongside genocide, war crimes, crimes of aggression, and crimes against humanity.

She has also, like Bolivia, lobbied the UN for a Universal Declaration for Planetary Rights. Albeit relying on the criminal law, ecocide is the same idea: extending ‘our’ rights to ecosystems, and invoking UN powers, because ecosystem destruction is the biggest threat to world peace.

Higgins’ definition of ecocide would be: “The extensive destruction, damage to or loss of ecosystem(s) of a given territory, whether by human agency or by other causes, to such an extent that peaceful enjoyment by the inhabitants of that territory has been severely diminished”.

To parse these clauses as a lawyer is a joyless, doomed pursuit. They are a good advocate’s dream: the sky is the limit, you might say. They fail a basic test of good law, especially a criminal law: certainty.

To how much life does Nature have a right, and a right to exist in what state? To confer this, “free from human alteration”, would deny humans a right to exist. Or are humans, too, part of Nature, so that their rights are part of the law? How does this, then, interact with our other, existing, rights: does it modify them? Given the right of nature “not to be affected” by mega-infrastructure, may we therefore have any such infrastructure, and what does “mega” mean? Does the “right not to be polluted” mean, polluted at all? Or not beyond ecosystems’ capacity to absorb and regenerate?

The Mokihinui hydro proposal, intensive dairying in the Mackenzie, Indonesian rainforest felling for palm oil might all, quite happily, meet Higgins’ definition of ecocide. What about a new subdivision? An apple orchard ploughed under for dairy farming? Ripping out my shelter belt, to put in a centre pivot? Does either part of the crime require intent?

Higgins, you see, is more evolved than I. I am, regrettably -- I cannot tell you how much this annoys me -- still thinking like a lawyer.

To give Nature the same rights as humans, without tackling the policy dilemmas that lie beneath -- what is the relationship between nature and us? how much destruction is too much? -- is a recipe for bad law.

Symbolically brilliant, however. Campaigners will love it. You may expect to find me saying so, some other time, wearing my other new hat.