The metric is biodiversity.
How many kinds of life are there, and are they thriving? What are the bottlenecks and boundaries for species that slow or stop their progress?
Well, as a living, all-consuming, extinction-level event, I'd say we are making the experiment more impossible. We are a confounding factor, a bias most foul, and the primary flaw in the experimental design.
If only there was guidance in terms of balancing our biological impact and capacity for sustainable development. If only there were some models that have and had worked for millennia. If only there were living groups who could share their wisdom.
If only.
So, for now, plunderous expropriation rules: violent, resource-heavy, rational modern warfare; apathetic, resource-heavy, throwaway consumer culture; and ignorant, resource-heavy, industrial machinations.
What could go wrong?