Certainly, unconscious things can have objective impacts on other physical things. Meteors can slam into our planet and make their presence quite unmistakable.
But my point about the Anthropocene has to do with the strangeness of our impact. Meteor impacts can be explained astronomically and geologically, without positing consciousness (or intelligent design). Locust behaviour is biological, not psychological, social, or spiritual/existential.
Our impact on the planet isn't just destructive or due to animal instincts to find food, shelter, or mates. We don't reach equilibrium with our environment. We clearly aim to transform and perfect nature technologically, according to our creative vision of an ideal world.
Explaining that anomalous impact seems to require that we posit a mental interface (thoughts and feelings), which enable us to range over stimuli, the genes, and other physical or biological causes.