One million species risk extinction due to humans: draft UN report

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

Delegates from 130 nations meeting in Paris from April 29 will vet the executive summary line-by-line. Wording may change, but figures lifted from the underlying report cannot be altered.

"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," Robert Watson, chair of the UN-mandated body that compiled the report, told AFP, without divulging its findings.

"The way we produce our food and energy is undermining the regulating services that we get from Nature," he said, adding 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.

- 'Mass extinction event' -

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 notes.

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

Scientists estimate that Earth is today home to some 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 percent.

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

- Population growth -

"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 ten years, just as we need to do that with climate," noted WWF chief scientist Rebecca Shaw, formerly a member of the UN scientific bodies for both climate and biodiversity.

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 finds.

Shifts in the distribution of species, for example, will likely double if average temperature go up a notch from 1.5 degrees Celsius (2.7 Fahrenheit) to 2C.

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

The 2015 Paris Agreement enjoins nations to cap the rise to "well below" 2C. But a landmark UN climate report in October said that would still be enough to boost the intensity and frequency of deadly heatwaves, droughts, floods and storms.

- Global inequity -

Other findings in the report include:

- Three-quarters of land surfaces, 40 percent of the marine environment, and 50 percent of inland waterways across the globe have been "severely altered".

- Many of the areas where Nature's contribution to human wellbeing will be most severely compromised are home to indigenous peoples and the world's poorest communities that are also vulnerable to climate change.

- More than two billion people rely on wood fuel for energy, four billion rely on natural medicines, and more than 75 percent of global food crops require animal pollination.

- Nearly half of land and marine ecosystems have been profoundly compromised by human interference in the last 50 years.

- Subsidies to fisheries, industrial agriculture, livestock raising, forestry, mining and the production of biofuel or fossil fuel energy encourage waste, inefficiency and over-consumption.

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