Time is running out for humanity to curb global warming that will plunge the planet into disastrous flooding, heatwaves and famines, a major UN report warns.
The study by hundreds of leading scientists says the world is ‘nearing the point of no return’ – but could still prevent catastrophe.
Deep cuts to greenhouse gas emissions need to start happening across the world, or temperatures on Earth will shoot past efforts to limit heating to 1.5C (2.7F), according to the report.
And every fraction of a degree of warming will ‘intensify’ the hazards to the planet, the report warns.
Devastating impacts will include melting of ice caps leading to rising sea levels, a loss of coral reefs and glaciers, as well as huge economic damage to agriculture, forestry, fishery, energy, and tourism.
The United Nations Intergovernmental Panel on Climate Change (IPCC) synthesis report has been agreed after a week of discussions in Interlaken, Switzerland.
It says the science is ‘unequivocal’ that humans have caused climate change.
The report warns that the Earth is currently on course for global warming of around 2.7C (4.8F) between 2081 and 2100 assuming an ‘intermediate’ level of greenhouse gas emissions, but it could be as low as 1.4C (2.5F) if emissions go ‘very low’ but as high as 4.4C (7.9F) if they go ‘very high’.
But it says the damage can be halted by ‘deep, rapid, and sustained reductions in greenhouse gas emissions would lead to a discernible slowdown in global warming within around two decades’.
To do so, the world will need to cut carbon dioxide emissions compared to 1990 levels by 48 per cent by 2030; by 65 per cent by 2035; by 80 per cent by 2040 and by 99 per cent in 2050.
In effect, the report urges that the world has to get as close as possible to ‘net zero’ emissions in just 17 years time.
Governments agreed in Paris almost eight years ago to try to limit temperature rise to 1.5C (2.7F) or at least keep it well below 2C (3.6F).
Since then, scientists have increasingly argued that any warming beyond the lower threshold would put humanity at grave risk.
Average global temperatures have already increased by 1.1C (2F) since the 19th century.