But thanks to people like Johan Rockstrom who has reminded us, our advances also gave us the science to recognize this and change behavior. His research has found nine "planetary boundaries" that can guide us in protecting our planet's many overlapping ecosystems. According to him if Earth is a self-regulating system, it's clear that human activity is capable of disrupting it. Johan Rockstrom has led a team of scientists to define the nine Earth systems that need to be kept within bounds for Earth to keep itself in balance.