Human actions risk making a million species extinct: UN

Biodiversity loss no less a threat than climate change, says report, noting they are linked

PARIS • Up to one million species face extinction due to human influence, says a draft United Nations report that painstakingly catalogues how humanity has undermined the natural resources upon which its very survival depends.

The accelerating loss of clean air, drinkable water, carbon dioxide-absorbing forests, pollinating insects, protein-rich fish and storm-blocking mangroves - to name but a few of the dwindling services rendered by nature - poses no less of a threat than climate change, says the report, which will be unveiled on May 6.

Indeed, biodiversity loss and global warming are closely linked, says the 44-page Summary for Policy Makers, which distils a 1,800-page UN assessment of scientific literature on the state of nature.

Delegates from 130 nations meeting in Paris from next Monday will vet the executive summary line by line.

The wording may change, but figures lifted from the underlying report cannot be altered, said Professor Robert Watson, chair of the UN-mandated body that compiled the report, without divulging its findings.

He said: "We need to recognise that climate change and loss of nature are equally important, not just for the environment, but as development and economic issues as well. The way we produce our food and energy is undermining the regulating services that we get from nature.

He added that only "transformative change" can stem the damage.

Deforestation and agriculture, including livestock production, account for about a quarter of greenhouse gas emissions, and have wreaked havoc on natural ecosystems as well.

The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) report warns of "an imminent rapid acceleration in the global rate of species extinction".

The pace of loss "is already tens to hundreds of times higher than it has been, on average, over the last 10 million years," it adds.

The report says: "Half-a-million to a million species are projected to be threatened with extinction, many within decades."

Many experts think a so-called "mass extinction event" - only the sixth in the last half-billion years - is already under way. The most recent saw the end of the Cretaceous period about 66 million years ago, when a 10km-wide asteroid strike wiped out most lifeforms.

Scientists estimate that the earth is today home to about eight million distinct species, a majority of them insects. A quarter of catalogued animal and plant species are already being crowded, eaten or poisoned out of existence.

The drop in sheer numbers is even more dramatic, with wild mammal biomass - their collective weight - down by 82 per cent.

Humans and livestock account for more than 95 per cent of mammal biomass.

World Wildlife Fund chief scientist Rebecca Shaw, who was formerly a member of the UN scientific bodies for both climate and biodiversity, said: "If we're going to have a sustainable planet that provides services to communities around the world, we need to change this trajectory in the next 10 years, just as we need to do that with climate."

The direct causes of species loss, in order of importance, are shrinking habitat and land-use change, hunting for food or illicit trade in body parts, climate change, pollution, and alien species such as rats, mosquitoes and snakes that hitch rides on ships or planes, the report says.

Said Prof Watson: "There are also two big indirect drivers of biodiversity loss and climate change - the number of people in the world and their growing ability to consume."

Once seen as primarily a future threat to animal and plant life, the disruptive impact of global warming has accelerated.

Shifts in the distribution of species, for example, will likely double if average temperatures go up a notch, from 1.5 deg C to 2 deg C.

So far, the global thermometer has risen 1 deg C compared with mid-19th century levels.

The report cautions against climate change solutions that may inadvertently harm nature.

The use, for example, of biofuels combined with "carbon capture and storage" - the sequestration of carbon dioxide released when biofuels are burned - is widely seen as key in the transition to green energy on a global scale.

However, the land needed to grow all those biofuel crops may wind up cutting into food production, the expansion of protected areas, and reforestation efforts.


A version of this article appeared in the print edition of The Straits Times on April 25, 2019, with the headline 'Human actions risk making a million species extinct: UN'. Print Edition | Subscribe