Complex sentence: Factor Ten is the radical idea that humanity must reduce resource turnover by 90 percent on a global scale within the next 30 to 50 years, and that human energy use and material flows is currently unsustainable and destructive to the environment.
Split into simpler sentences: Factor Ten is the radical idea that humanity must reduce resource turnover by 90 percent on a global scale within the next 30 to 50 years. Human energy use and material flows is currently unsustainable and destructive to the environment.