Earth’s ability to sustain human life in peril
Earth’s life support systems have been so damaged by human activity that the planet is now “well outside the safe operating space for humanity,” scientists warn. In what’s billed as the “first scientific health check for the entire planet,” reports Smithsonian Magazine, researchers at the University of Copenhagen in Denmark looked at nine planetary boundaries, benchmarks that lay out the parameters for human survival. They concluded that six of the boundaries have already been exceeded: climate change, biodiversity, freshwater availability, land use, biogeochemical balance (which measures nutrient runoff), and novel entities (which encompasses microplastics and radioactive waste). Two of the remaining three, air pollution and ocean acidification, were deemed at risk of being breached. The only one out of danger was atmospheric ozone, which has recovered thanks to decades of global efforts to phase out chlorofluorocarbons. But researchers say we shouldn’t despair: The boundaries, which were assessed using more than 2,000 studies, are not irreversible tipping points. Instead, they are the levels beyond which the risk of fundamental changes to the planet’s ability to maintain life rise significantly. “Crossing six of the nine boundaries isn’t a guarantee of disaster,” says lead author Katherine Richardson. “It’s a wake-up call; it’s like your blood pressure. If your blood pressure is up, it doesn’t necessarily mean you’re going to have a heart attack. But it does tell you the risk is too high, and you try to put it down.”