Living Will?

A 10 year, multi-agency study by the Deep Carbon Observatory has used a combination of 5 km bore holes on land surfaces and undersea drilling sites to study living carbon-based organisms in the Earth's crust (https://www.theguardian.com/science/2018/dec/10/tread-softly-because-you-tread-on-23bn-tonnes-of-micro-organisms). They estimate that more than 20 billion tons of microorganisms  live below the surface. This is a greater biomass than the planet's current human population, in spite of the region being characterised by intense heat; sparse nutrition and mind-boggling pressures. Some organisms appear to have survived (largely in a state of stasis) buried in situ for millions of years. The scientists speculate as to whether colonisation of life zones of the planet have gone from surface to interior or vice versa. That actually may not matter too much as, I suspect, that life, being opportunistic, will take advantage of vacancies that occur in either location. So, if  humans manage, by their actions, to eliminate much of the life on the surface, some 'deep life' will come to the surface, certainly speeding up the re-population process.