Slow refinement, and avoidance of development directions that produce excessive amounts of unutilizable waste to which the only solution is sequestration.
Avoid unsustainable practices such as excessive monoculture farming; constrain packaging to forms with applications for secondary reuse, or compostability.
Develop technologies that further "closing the loop" on current technologies. Petrophagic bacteria to break down plastics; high carbon sequestering, fast growing plant life.
Concentrate medical research on trying to confirm treatment protocols w.r.t. "traditional" plants/phages/etc.
Focus on nuclear power, and nuclear fuel reprocessing.
Keep things from going over the Rubicon environmentally, and you've suddenly bought everyone enough time to get their stuff together to equalize development levels the world over. Seems humanity's biggest problem other than not paying attention to environmental change is figuring out how in the heck to coexist with each other.
EDIT:
This is just the parts of the mental TODO list that are sitting on top of my head. I've got entire sections that are highly dependent on getting access to information I simply don't have the time/manpower to personally chase down for relevance.
Basic gist is to shore up our present level of development, change up the incentives/structural characteristics of the international market to attempt to decrease the need to move goods as much; shore up and propogate the technosphere so there's a more consistent level of technological development to avail ourselves to in being able to more accurately track, model, and calculate the effects of continuing development as they propagate through the biosphere in real time. This will also be necessarily bundled with significant increases in funding/incentives for research in the Life/biological/ecological Sciences, as well as further refinement of meteorological sciences.
We need to know as much about the state of our biosphere as a whole in the present to equip us to manage our continued development without sacrificing the larger part of the biosphere in doing so.
Parallel research efforts would also be undertaken in porting closed loop ecologies (with humans in the mix) into extreme environs to double down on being able to increase potential biological footprint.
Emergency backup biosphere tucked safely away for a rainy day are pretty cool too.
Anyway. Didn't actually expect anyone would actually ask. So used to people avoiding it.