Mankind’s Damage to Freshwater Biodiversity Could Take Millions of Years to Heal

Researchers warn that the current rate of biodiversity decline in freshwater is outpacing the rate recorded during Earth’s last major extinction event nearly 66 million years ago.

Lake Volvi (Greece) temporarily dries up as a consequence of excessive irrigation for agriculture paired with climate change – one of many examples of a freshwater system under human impact. (Credit: C. Albrecht)

(CN) — A new study released Friday details the massive scope of human-driven biodiversity loss among freshwater ecosystems — and the millions of years it will likely take to reverse the damage.

Scientists and environmental experts the world over have made it clear that Earth is facing a biodiversity crisis like no other. Countless species across the planet — from the giant pandas of China to the blue whales of the ocean — have found themselves on the brink of extinction, with much of the blame resting squarely at the feet of human impact.

Throughout the centuries humans have devastated animal habitats, driven global climate change to new and dangerous heights and have generally made it more challenging for Earth’s wild creatures to find safe footholds for their survival. This human-driven damage to Earth’s environment has brought on a biodiversity crisis so severe that many experts have dubbed it the sixth mass extinction event on Earth — nearly 66 million years after the fifth wiped the dinosaurs from existence.

A new study published Friday in the journal Communications Earth & Environment explores just how long Earth will be reeling from the consequences of this crisis and the data suggests those consequences may outlast the very hands that caused them in the first place.

To better understand the timetable for Earth’s current extinction rates and recovery time, an international team of biologists, paleontologists, geologists and modelers looked to compare the data of our current crisis with the previous one that saw an asteroid destroy roughly three-quarters of all species on the planet.

Researchers specifically honed in their observations on data collected from freshwater species, groups that stand as some of the critically threatened today and help operate some of the most crucial biodomes on the planet.

“Losing species entails changes in species communities and, in the long run, this affects entire ecosystems,” Thomas Neubauer, lead author of the study, said in a statement. “We rely on functioning freshwater environments to sustain human health, nutrition and fresh water supply.”

To help study this, researchers collected over 3,000 living and fossilized snail species that collectively accounted for nearly 200 million years’ worth of data to accurately gauge how quickly animal species go extinct or recover over time.

Their results paint a grim future for Earth’s future freshwater ecosystems. While experts found that the extinction rate for freshwater creatures during the last mass extinction event was higher than previous estimates, it doesn’t even come close to the one we are experiencing today. Experts say that on average, today’s extinction event is roughly three orders of magnitudes greater than the one caused by the asteroid millions of years ago.

Researchers warn that it won’t even be long until this rate begins to catch up with us. According to their data models, by 2120 — less than a century away — nearly a third of all species living in freshwater will have disappeared from the world.

The data reveals that at this current rate, the planet is losing species at a level never once reached by any extinction event known in Earth’s history.

But what is perhaps even more troubling than how quickly species are dying is how long it will take Earth to recover. To understand this, researchers calculated that after the asteroid that destroyed the dinosaurs struck, it took the planet about 12 million years for emerging species and threatened species to find harmony once again.

While 12 million years sounds like a long recovery time, it may pale in comparison to the timetable of our current crisis. Because our current extinction rate exceeds the rate of the previous extinction event so immensely, researchers warn that our recovery time may be just as dire.

Experts say that even if our biodiversity loss were suddenly halted right away, humankind has already guaranteed that the legacy of our environmental harm will long outlive us.

“Even if our impact on the world’s biota stops today, the extinction rate will likely stay high for an extended period of time,” Neubauer said. “Considering that the current biodiversity crisis advances much faster than the mass extinction event 66 million years ago, the recovery period may be even longer. Despite our short existence on Earth, we have assured that the effects of our actions will outlast us by millions of years.”

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