The crushing impacts of climate change will hit sooner than expected – with millions of people afflicted by hunger, drought and disease in the coming decades, a leaked UN report has warned.
The outlook for the planet is bleak, even if global climate targets are met.
Scientists from the Intergovernmental Panel on Climate Change say species extinction, extreme weather, ecosystem collapse and the spread of disease will be deeply felt within the next 30 years.
The draft report, which was seen by AFP but which will not be made public until next year, is the most comprehensive assessment on how global warming will affect both the planet and humankind.
With dangerous thresholds closer than thought, the choices that societies make now will determine whether our species thrives or simply survives during the 21st century, the report said.
While slashing emissions and promoting plant-based diets can limit the damage to human health, the fallout resulting from decades of unchecked carbon pollution will be unavoidable in the short term.
Many land and marine ecosystems had reached, or surpassed, their ability to adapt to climate change, the scientists said.
The world has warmed by more than 1° Celsius since pre-industrial times, and is on track for 2.9C of warming under existing policies. The Paris Agreement aims to limit warming to “well below” 2C.
The IPCC report found that in a world that was 2C hotter, animals such as penguins, polar bears, seals and corals reefs would be threatened.
In addition, 15 percent of the planet's permafrost would be lost by 2100, releasing up to 67 billion tonnes of carbon from the frozen soil into the atmosphere.
Warming of between 2C and 3C would see more than half of life on earth threatened with extinction.