A major new report backed by the United Nations finds invasive species are spreading around the world at an unprecedented rate, driving extinctions, transmitting diseases and threatening food supplies for millions of people. Ecologist Helen Roy, who co-authored the report by the Intergovernmental Platform on Biodiversity and Ecosystem Services, says more than 3,500 harmful invasive species are “seriously threatening nature,” while causing untold economic damage to humans.

Helen Roy: “But of those costs that are tangible that we’ve been able to gather together, we can see it’s $423 billion annually. But we also know that looking back, then these figures have been quadrupling every 10 years, and we have no reason to think that that isn’t going to be happening into the future.”