The world’s leading climate scientists this week are preparing the final version of a cornerstone United Nations report to assess whether global temperatures can be kept in check this century to prevent the most damaging effects of global warming.

The U.N.’s Intergovernmental Panel on Climate Change (IPCC) is meeting this week in Incheon, South Korea, and plans to discuss the report, which will determine whether global warming this century can be kept to a limit of 1.5 degrees Celsius (2.7 degrees Fahrenheit).

The IPCC aims to release the Special Report on Global Warming of 1.5C on Oct. 8.

“The main issue of the report discussion will be around how we can get to a 1.5 degree limit and what will be the carbon (emissions) budget available to do that,” said Friederike Otto, acting director of the Environmental Change Institute at Oxford University.

In 2015, nearly 200 nations pledged in Paris to limit the global average temperature rise to “well below” 2C above pre-industrial times while “pursuing efforts” for a tougher 1.5C goal.

The IPCC report, seen as the main scientific guide for combating climate change, will provide guidance on the required actions to combat climate change.

There has already been a rise of 1C since the mid-1800s as industrialization produced rising emissions of carbon dioxide, the main greenhouse gas blamed for climate change.

According to a draft of the report seen in June but subject to change, governments can still limit temperatures below 1.5C but only with “rapid and far-reaching” action.

The draft said current pledges in the Paris Agreement are too weak to limit warming to 1.5C.

The document said there was a need to increase renewable energy output by 60 percent between 2020 and 2050, while energy from coal should be scaled back by two-thirds. By 2050, that means renewables would supply between 49 percent and 67 percent of primary energy.

Since the agreement was reached, U.S. President Donald Trump has withdrawn the United States from the Paris accord.

“On the policy side of reducing emissions I think there will be a lot of points of disagreement,” said Michael Grubb, professor of international energy and climate change policy at University College London.

“If they fail to reach an agreement, it will be down to a fundamental division on climate justice between fossil fuel producers (and the U.S. administration) and more vulnerable countries such as small island states who feel their existence is under threat,” Grubb said.