Earth is on brink of sixth mass extinction

Mammals, birds and amphibians are currently becoming extinct at rates comparable to the previous five mass extinctions when “cataclysmic forces“ -such as massive meteorite strikes and supervolcano explosions -wiped out vast swathes of life, including the dinosaurs.

The growing human population -which has increased by 130% in the last 50 years and is set to rise to more than 10 billion by 2060 -and our increasing demand for resources as we become wealthier is ramping up the pressure on the natural world.Tens of thousands of species -including 25% of all mammals and 13% of birds -are now threatened with extinction because of over-hunting, poaching, pollution, loss of habitat, the arrival of invasive species, and other human-caused problems.

But the researchers said it was not “inevitable“ that this process would continue. There is still time for humans to turn the situation around by protecting habitats, changing our diets to less land-intensive food, and taking other forms of conservation.

In one of a series of papers in Nature, a team of international scientists wrote: “There is overwhelming evidence that habitat loss and fragmentation, over-exploitation of biological resources, pollution, species invasions and climate change have increased rates of global species extinctions to levels that are much higher than those observed in the fossil record.“ This loss of biodiversity could “substantially diminish the benefits that people derive from nature“, they warned.

In order to preserve such “ecosystem services“, policies should be designed to “secure the valuable and often irreplaceable benefits of biodiversity for future generations, even under conditions of rapid global change“, the paper added.

Another paper painted a bleak picture of humans’ long history of wiping out other animals. “Humaninfluenced extinctions began when modern humans moved out of Afri ca,“ it said. “Successive waves of extinctions in Australia (50,000 years ago), North America and South America (10,000-11,000 years ago) and Europe (3,000-12,000 years ago) were driven largely by a combination of hunting by humans and natural climate change. By 3,000 years ago, Earth had lost half of all terrestrial mammalian megafauna species and 15% of all bird species.“

The researchers said that since 1500AD, human destruction of wildlife had “accelerated“. It said “urgent“ action was needed to ensure that “sufficient habitats will remain to preserve the viability of species in the long term and to guarantee that such habitats are well managed“.