Paris: The degradation of nature threatens mankind just as much as climate change, Robert Watson, outgoing head of the UN science panel for biodiversity, has warned ahead of a stark assessment of the state of our planet.
The former head of the Intergovernmental Panel on Climate Change, Watson has a unique perspective on how global warming and biodiversity loss - two of the most pressing problems humanity faces - overlap and exacerbate each other.
He spoke to AFP ahead of the unveiling Monday of a UN assessment of Nature - the first in 15 years - written by 150 scientists and drawing from 15,000 published studies and government reports.
Is the destruction of Nature as much of a threat to humanity as climate change?
Degrading Nature affects food and water security, the regulation of climate, even social cohesion. It threatens human wellbeing at least as much as climate change, and the causes and solutions for both overlap.
The way we produce food and energy undermines the 'services' we get from Nature that protect us against air pollution and floods.
The long-term degradation of soils and lost soil microbes will compromise food production, and the availability of clean water. Then there is the loss of pollination services, which threatens crops worth hundreds of billions of dollars each year.
Are we entering a 'mass extinction event'?
In each of the five previous mass extinctions, we lost about 75 percent of species. If you accumulate species loss over the last 500 years, we have lost two percent at most.
Data and records suggest about 20 per cent of species are threatened with extinction over the next 100 years. If we were to lose an additional 20 per cent every 100 years, you might see a mass extinction in 250-500 years.
If only the critically threatened species vanished by the end of this century, and extinctions continued at that rate, it would take between 900 and 2,300 years to reach the 75 per cent threshold.
So we might be at the beginning or moving toward a sixth mass extinction, but there is a long way to go before you could say we are fully in one.
The main causes of species decline?
The five main drivers of biodiversity loss are land use change (including agriculture), over-exploitation (mostly hunting for food), invasive alien species, pollution and climate change. There are also two big indirect drivers: the number of people in the world and consumption per capita.
By 2050, the population will go up from 7.5 to 9.5 or 10 billion, and by the end of the century plausibly to 11 billion. At the same time, world economic growth will double or triple by 2050.
Developed countries will only increase one or two percent per year in GDP. The economies of developing countries are likely, on average, to grow by four per cent.
