When you take an interest in reducing humanity’s impact on the biosphere, it becomes apparent that there are simply too many humans. It is generally accepted that the planet can support only 2 billion people by natural means. The equation is simple: sun’s energy enters the biosphere and is converted to stored energy (by plants), and then consumed by life. Energy also is used to fuel weather and other phenomena and it is radiated out too.
Currently humans number over 6.5 billion, or three times what the biosphere can support. How can that be?
Simple really. We are consuming millions of years of stored energy in a couple of centuries by using fossil fuels. Oil and coal were created by compacting millions of years of plant growth into denser compounds than compost. That stored energy of the sun can not be replaced.
Population decline can save the planet. It was mentioned to me recently that a fertility rate of 1.3 would reduce the global population to 2 billion in 30 years. That means that females produce 1.3 offspring rather than the 2-3 average now being maintained. That is not necessarily easy to achieve; we have lots of friends with more than 3 children (ourselves included). And its harder in agricultural economies that are urbanising, such as those in Africa. Education and cultural acceptance of people without marriage or children is important.
But the number offer some hope. They show that population reduction is plausible and possible within a time frame that will redress the impact of humanity (pollution, climate change, biosphere destruction, species extinction etc). So, stop making babies. Consider sharing children and their rearing among small groups; maybe siblings would contribute more to the raising of your children and not have any themselves.