PARIS, France (AFP) — Overconsumption and unsustainable farming are fuelling overlapping crises in nature and the climate, putting crucial ecosystems such as coral reefs at imminent risk of destruction, a landmark United Nations (UN) report said Tuesday.

The assessment by the UN’s expert biodiversity panel lays bare the complex interplay between nature loss, global warming, and threats to water, food and health — and the role of humans in driving these crises.

Three years in the making, their report was agreed by nearly 150 governments after days of painstaking debate, and followed disappointing outcomes for the planet at a string of UN summits.

Tackling any of these challenges in isolation dooms progress on the others, stressed the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES).

This poses “a real danger in that we’ll solve one crisis whilst also making others worse”, said Paula Harrison, one of the report’s lead authors.

In a potent illustration of the multi-pronged threat posed by humanity, the report warned that fast-warming seas, overfishing and ocean pollution put coral reefs on course for extinction within a few generations.

“Coral reefs are the most endangered ecosystems and may disappear globally in the next 10 to 50 years,” said the sweeping report by scores of international scientists.

Such a catastrophic loss would affect a billion people who depend on reefs for food, tourism income, and protection from storms.

The true cost of such destruction is often hidden or outright ignored, the report’s authors said.

They estimated that fossil fuels, farming and fisheries could inflict up to US$25 trillion a year in accounted costs — equivalent to a quarter of global GDP.

“We’re just neglecting those trade offs,” economist James Vause, who contributed to the report, told AFP.

Nature underpins more than half the global economy but governments are spending vastly more on its destruction than conservation.

Vause said US$200 billion annually was spent on biodiversity yet 35 times as much — some US$7 trillion — went into subsidies and other negative incentives that harmed the planet.

The report underlined the particularly damaging toll of unsustainable farming, saying it “contributed to biodiversity loss, greenhouse gas emissions, and air, water and land pollution”.

Fisheries were “approaching tipping points”, it added.

Affluence — not need — was largely behind a growing appetite for food that was being met in part through exploitative farming methods that also risked the emergence of new pathogens.

Curbing the overconsumption of red and processed meat would help promote more sustainable farming practices and improve health outcomes.

A huge amount of all food grown is wasted while 800 million people go hungry every day, Pamela McElwee, the report’s other lead author, told AFP.

“This current system doesn’t have to be the way it is… (it) is not only not working for nature, it’s not working for a big chunk of the population,” McElwee said.

Treating these interlinked crises as separate problems was “duplicative and may be wasting money”, she added.

It was also counterproductive.

For example, planting trees in an effort to address global warming could have a negative knock-on effect for local plant or animal species if done inappropriately.

By contrast, involving communities in the management of marine protected areas had delivered upsides for the environment but also boosted tourism revenue and fish catch for local people.

In California, flooding rice fields instead of burning crop residue improved air quality but also restored salmon populations and sheltered migratory birds.

In another example, the authors said treating the parasitic disease bilharzia — which affects 200 million people annually — as an environmental challenge, not just a health one, had improved reinfection rates.

In Senegal, cases were cut 32 per cent in children and access to clean water improved when lakes were cleared of vegetation on which disease-transmitting snails feed.