PLANET IN DANGER. A protester holds a sign reading 'Planet in danger' during a climate change protest in Paris,on September 21, 2019. Photo by Lucas Barioulet/AFP
The report"highlights the urgent need for the development of concrete actions that halt global warming and the worst effects of climate change," said its authors, the Science Advisory Group to the summit. The 2015 Paris Agreement saw countries lay out national targets to reduce their emissions in order to limit long term temperature rise by under two degrees Celsius or ideally 1.5 degrees Celsius above pre-industrial levels.
The current levels of ambition would need to be tripled to meet the two degrees Celsius goal and increased five-fold to meet the 1.5 degrees Celsius goal -- technically still possible. "The last time Earth's atmosphere contained 400 parts per million CO 2 was about 3-5 million years ago," the report said.