It took humans around 200,000 years to reach a global population of one billion. But, in two hundred years we’ve septupled that. In fact, over the last 40 years we’ve added an extra billion approximately every dozen years. And the United Nations predicts we’ll add another four billion—for a total of 11 billion—by century’s end. Despite this few scientists, policymakers, or even environmentalists are willing to publicly connect incredible population growth to worsening climate change, biodiversity loss, resource scarcity, or the global environmental crisis in general.