The world faces extreme heat, drought, floods and poverty if global warming passes the 1.5C mark, a major UN report has found.
Global warming should be limited to 1.5C above pre-industrial levels rather than 2C to ensure the impacts of climate change are less extreme, the Intergovernmental Panel on Climate Change (IPCC) report says.
Sea level rises would be 10cm lower with a 1.5C temperature rise compared to 2C by 2100, while there would be worse impacts on coral reefs and the Arctic at higher temperatures.
The world has seen 1C of warming so far, with consequences such as more extreme weather already being felt, and there is more to come as temperatures continue to rise, the report says.
It warns that every fraction of additional warming could worsen the impact.
The report says this goal is possible but will require fast and far-reaching changes to power generation, industry, transport, buildings and potential shifts in lifestyle such as eating less meat.
It will also require action to take excess carbon emissions out of the atmosphere.
Promises made by countries to cut their emissions up to 2030 will not limit global warming to 1.5C even if action is massively scaled up after the end of the next decade, the report warns.
Prof Corinne Le Quere, from the University of East Anglia, said: "For the UK, this means a rapid switch to renewable energy and electric cars, insulating our homes, planting trees, where possible walking or cycling and eating well – more plants and less meat – and developing an industry to capture carbon and store it underground.
"We need to extend this kind of progress on renewables to other areas."