Original sentence: While some argue there is now clear scientific evidence that humanity is living unsustainably, and that an unprecedented collective effort is needed to return human use of natural resources to within sustainable limits, it is not clear that a goal of sustainable living is a requirement for the continued survival of the human species
Edited sentence: However, there is now clear scientific evidence that humanity is living unsustainably, and that an unprecedented collective effort is needed to return human use of natural resources to within sustainable limits