As matter is finite within our worlds sphere, what would the total number of lifeforms which could be sustained
I’m sure there are lots of ways to answer that. We have exceed the natural limit of nitrogen that plants derive from the air. To grow food, we us nitrogen from fossils. Last checked, our population limit should be 4 billion
Of course it does not depend so much on the number of people as on their lifestyle.
Consider that in the first 2 million years humans lived within the limitations of availability of natural resources , we were hunter/gatherers like many other species.
without any impact on the Earth’s biosphere.
Then came the Industrial Age in 1760 and in the following 460 years we have managed to start the 6th (man-made) extinction event, also known as the Holocene Extinction, by our wanton use of sequestered carbon to drive our industries that just makes life more “luxurious” and to make financial “billionaires”, which is incompatible with the concept of recycling resources and living in symbiosis with nature.
The Holocene extinction, otherwise referred to as the sixth mass extinction or Anthropocene extinction, is an ongoing extinction event of species during the present Holocene epoch (with the more recent time sometimes called Anthropocene) as a result of human activity. The included extinctions span numerous families of bacteria, fungi, plants and animals, including mammals, birds, reptiles, amphibians, fish and invertebrates.
With widespread degradation of highly biodiverse habitats such as coral reefs and rainforests, as well as other areas, the vast majority of these extinctions are thought to be undocumented, as the species are undiscovered at the time of their extinction, or no one has yet discovered their extinction. The current rate of extinction of species is estimated at 100 to 1,000 times higher than natural background extinction rates.