Damage caused by invasive species adding up

Invasive species have got a lot of damage to answer for over the last 50 years — roughly in the order of $1 trillion. Now, scientists are warning there’s even more to come.

From ruining crop yields to wreaking havoc on human health, invasive species have been responsible for an array of global maladies over the past half century that costs the world $1.28 trillion, researchers said in a recent paper in scientific journal Nature. Though the number is staggering to comprehend, it is likely an underestimation, they said.

The costs will surge as these socalled biological invasions — which occur when foreign animals, plants or pathogens are introduced into new regions — become more frequent and exacerbated by climate change and globalization.

“This trillion-dollar bill doesn’t show any sign of slowing down, with a consistent three-fold increase per decade,” lead author Christophe Diagne of Université Paris-saclay said in a statement. “The global costs of invasive alien species are so massive that we spent months verifying our models and this overall estimate, to ensure we were not exaggerating.”

The acceleration can be partly explained by increased global trade and transport options that have created more opportunities for invasions. Growing land take for agriculture and infrastructure has also made societies more vulnerable to impacts from these invasions.

That an alien species can cause outsized economic and human loss is hardly a surprise in recent times. One only has to look at the COVID-19 pandemic still unfolding to grasp the depth of the economic scarring inflicted by a virus that could be traced back to a live-animal wet market in Wuhan, China. The grim forecast mirrors the sense of urgency that public health officials have had for decades in warning that such a devastating outbreak was bound to happen.

The average cost of damage exceeded the gross domestic product of 50 countries on the African continent in 2017, and is more than 20 times higher than the total funds available to the World Health Organization and United Nations combined, the researchers said. Emerging diseases such as COVID-19 were not included in the tally.

“We found that costs roughly doubled every six years, a pattern that mimics the continuous increase in the number of alien species worldwide,” according to fellow researcher Corey Bradshaw from Flinders University.