On Tuesday, the human population reached eight billion people, according to an estimate by the United Nations. While population growth has slowed in recent years, it still took about a decade to add the last billion people. Meanwhile, humankind is continuing to do irreparable harm to the planet, including climate change, accelerated species extinction and ecosystem collapse. We’re also straining the planet’s ability to sustain this many people, as revealed by water scarcity for billions of people — all while people in more affluent countries are responsible for far more than their fair share of the harm. Today we’re joined by Céline Delacroix, adjunct professor at the University of Ottawa’s School of Health Sciences and the Director of the FP/Earth project with the Population Institute, to discuss how it got to this point, what it means for people and the planet, and where we go from here.