"That garden of Eden is full of old rubber truck tires and tin cans right now, you know." — Gary Snyder
We now have the technology to fulfil the needs of humanity without damaging the biosphere for other organisms. However, much damage has already been done in the centuries it took for us to evolve to this point. Whole lakes and rivers have been rendered lifeless by pollutants. Lush forests are now blank cornfields. The oceans are full of plastic and even the atmosphere itself seems to have been altered.
But we have in our toolbox several effective ways of restoring the environment to its lost splendour.
One method of environmental repair is bioremediation. This is based on the magnificently-named microbial infallibility hypothesis. The microbial infallibility hypothesis states that bacteria will evolve to use any (or nearly any) carbon-based substance in their environment as a food source. So bacteria can be (and have been) bred to eat up oil slicks, sulphate fertilizers, pesticides and other pollutants. Nanotechnology, when it is developed, could be turned to a similar role.
Polluted waterways can be cleaned by floating islands. These are simply rafts with plants on them and create a catalyst for life, from microbes to carnivores, to thrive. The microbes and plants use the pollutants of the water as a food source, purifying it.
Certain useful plants, such as moringa olifera and leucaena leucocephala are particularly effective at rapidly restoring soil fertility and creating an environment in which other plants can grow. These can be planted in their thousands in areas lost to deforestation and desertification. Certain plants like hemp can be used as 'mop crops' to remove contaminants from soil. Hemp has been planted extensively around Chernobyl and has been very effective at destroying the radioactive contaminants there. This is known as phytoremediation.
Another subset of bioremediation is mycoremediation - environmental repair using fungi. Fungi were the first lifeform to come onto land and they prepared the rocky earth for plant life to flourish. Fungi were able to do this because they can digest an astonishing array of substances including rocks, crude oil, explosives like TNT and chemical warfare agents like VX and sarin gas.