Invasive species cost the world more than $400 billion a year, UN report finds

Sep 5, 2023, 10:31am EDT
Invasive water hyacinth. Picryl
Jeronimo Gonzalez/

Invasive species cost the world more than $400 billion — roughly 0.5% of global GDP — every year, an amount that has quadrupled each decade since 1970, a United Nations report found. At least 3,500 invasive species harmful to both the world’s flora and fauna have been spread by human trade and travel, sometimes causing species to go extinct or destabilizing a region’s ecosystem. Roughly 200 new such species are spread every year, potentially worsening the toll on the global economy.

The Americas are the worst affected region, with more than a third of all invasive species, followed closely by Europe and Central Asia. The problem, however, impacts almost all of the world’s ecosystems. “It would be an extremely costly mistake to regard biological invasions only as someone else’s problem1 ,” one of the report’s authors said. While the specific species that wreak havoc vary in different places, they pose global risks and challenges with “very local impacts,” the report said, affecting people from all backgrounds and communities, including those in Antarctica.

Maui’s recent wildfires illustrate the destructive impact that invasive species can have on an ecosystem. The relentless spread of nonnative grass species — imported to feed livestock on lands formerly occupied by the island’s once-thriving sugar cane plantations — is largely to blame for feeding the wildfires that ravaged Maui last month. “These grasses are highly aggressive, grow very fast and are highly flammable2 ,” said the coordinator of the Pacific Fire Exchange, a science-sharing project based in Hawaii. “That’s a recipe for fires that are a lot larger and a lot more destructive.”

Invasive species are thought to be a major factor in around 60% of global animal and plant extinctions3 , a professor of Forestry Sciences at the University of Concepcion in Chile said. As the world’s climate warms, invasive species that used to thrive closer to the tropics are expanding their habitats towards the poles. Eradication programs — especially on islands which are disproportionately affected by invasive species — have had high success rates, according to the U.N. report. However, the authors emphasized that governments should focus their resources on prevention rather than eradication. "It’s much more cost-effective to prevent the introduction of invasive species such as taking biosecurity measures, border controls and risk analysis of non-native species,4 ” one of the authors wrote.