Fish stocks may run out by 2048 and more than half of Africa's bird and mammal species lost by 2100 unless drastic measures are taken, according to four comprehensive reports released in Medellin.
Up to 90 percent of Asia-Pacific corals will suffer "severe degradation" by 2050, while in Europe and Central Asia, almost a third of known marine fish populations, and 42 percent of land animals and plants, are in decline.
"This alarming trend endangers economies, livelihoods, food security and the quality of life of people everywhere," warned the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES).
Compiled by nearly 600 scientists over three years, the reports underline that nature provides humans with food, clean water, energy, and regulates Earth's climate -- just about everything we need to survive and thrive.
"We're undermining our own future well-being," IPBES chairman Robert Watson said of the findings.
"Biodiversity continues to be lost across all of the regions of the globe. We're losing species, we're degrading ecosystems... if we continue 'business as usual', we will continue to lose biodiversity at increasing rates."
The IPBES assessment divided the world into four: the Americas, Africa, Asia-Pacific, and Europe and Central Asia -- the whole planet except for the Antarctic and the open seas.
Volunteer scientists combed through some 10,000 scientific publications for the most extensive biodiversity survey since 2005.
The findings were summarised in four reports approved by 129-member IPBES' member countries in Colombia. They contain guidelines for governments to make biodiversity-friendlier policies in future.
The texts make for grim reading, and come in the same week that the death of Sudan -- the world's last northern white rhino male -- served as a stark reminder of the stakes.
Mass extinction will continue
For the Americas, the survey warned that species populations -- already 31 percent smaller than when the first European settlers arrived -- will have shrunk by about 40 percent by 2050.
An estimated 500,000 square kilometers of African land is estimated to be degraded, it added.
The continent will suffer "significant" plant losses, and its lakes will be 20-30 percent less productive by 2100.
In the European Union, meanwhile, only seven percent of marine species assessed had a "favourable conservation status".
"If we continue the way we are... the sixth mass extinction, the first one ever caused by humans will continue," Watson old AFP.
Scientists say mankind's voracious consumption of biodiversity has unleashed the first mass species die-off since the demise of the dinosaurs -- only the sixth on our planet in half-a-billion years.
Demand will grow
In many places, climate change driven by burning fossil fuels for energy was worsening the loss of biodiversity, the reports found.
"This is what we've got to get across to policy makers: we have to look at climate change and biodiversity together," Watson said.
"Climate change affects biodiversity, changes in our natural vegetation affects climate change. And both of them, if we don't do this correctly, will undermine many of the United Nations Sustainable Development Goals: clean water for everyone, food security for people, energy security, human security, equity."
There are plenty of hurdles.
"Economic growth is going to continue. Population growth is going to continue to 2050, therefore demand for resources will grow," said the IPBES chairman.
Even at best-case-scenario levels, global warming will continue adding to species loss, which will cause further degradation of ecosystems.
But the scientists point to possible solutions: creating more protected areas, restoring degraded zones, and rethinking subsidies that promote unsustainable agriculture.
Governments, businesses, and individuals must consider the impact on biodiversity when taking decisions on farming, fishing, forestry, mining, or infrastructure development.
Different regions will require different solutions, said Watson.
"It's not too late" to halt or even reverse some of the harm, he said.
"Can we stop all of it? No. Can we significantly slow it down? Yes," Watson said.
The IPBES will bring out a fifth report on the global state of soil, fast being degraded through pollution, forest-destruction, mining, and unsustainable farming methods that deplete its nutrients.