A new United Nations report has warned that unprecedented changes across all aspects of society are needed in order to limit risky global warming.
Here is what you need to know.
Global Warming of 1.5 °C is the first in a series of Special Reports to be produced in the IPCC's Sixth Assessment Cycle.
The report outlined the changes they believe need to be made for the temperature rise to be limited to 1.5ºC "The good news is that some of the kinds of actions that would be needed to limit global warming to1.5ºC are already underway around the world, but they would need to accelerate", said Valerie Masson-Delmotte, Co-Chair of Working Group I.
While it is not said that it is impossible to limit global warming to 1.5℃, however, scientists have said that attaining it would be a very hard task.
Director Dr Richard Dixon said: "Today's IPCC report is an unprecedented warning on climate change".
This latest report - backed by the United Nations - says the scale of the challenge is vast and will be expensive to carry out.
"It shows that a 1.5C world will be a nightmare but a 2C world would be unthinkable".
The WWF called on the European Union to take urgent action to limit global warming to 1.5ºC, saying in a press release: "Approved by 195 governments, the report underscores the small window of opportunity we have to make immediate, deep and transformational changes - without which the world we know will be irreversibly changed".
Based on those promises, we are heading for 3C by 2100 and even warmer after that.
How can all that be done? "But it will require unprecedented and collective climate action in all areas". The changes include a rapid switch to electric vehicles, huge expansion of renewable energy and closing hundreds of coal-fired power stations.
Why make all that effort for 0.5C?
"Every extra bit of warming matters, especially since warming of 1.5°C or higher increases the risk associated with long-lasting or irreversible changes, such as the loss of some ecosystems", Co-Chair of IPCC Working Group II Hans-Otto Pörtner said.
Climate scientists have been studying the effect of a global temperature rise of 3.6 degrees Fahrenheit (2 degrees Celsius) over preindustrial levels and have determined that is the maximum possible warming before sea level rise, drought, and other climate-change effects become catastrophic. The half degree change would impact nature significantly as up to 90% of warm water coral reefs are predicted to disappear when global warming reaches 1.5℃, however, it the reefs will still have a 10% rate of survival, which is higher than what will survive when the temperature reaches 2℃.
- 20-40% of the global population have experienced more than 1.5C of warming in at least one season.
The IPCC does not do any of its own research, so the report draws on more than 6,000 research papers to reach its conclusions. The summary for policymakers issued yesterday was discussed and approved by representatives of all 195 countries.
"This means that any remaining emissions would need to be balanced by removing Carbon dioxide from the air", the report has found.
The conference itself, incidentally, will be the center of considerable attention as, at the gathering, according to the IPCC in the release, governments will review the Paris Accord, all, of course, with the ultimate aim of combating world climate change.