The landmark 2018 report on climate change from the IPCC

It seems to me that the main new thing here is the urgency resulting from the failure of decision-makers to be realistic and stop kicking the can down the road... It is too late to stop damaging climate change. It remains to try and limit the disastrous consequences. 

According to a BBC report:

"Keeping to the preferred target of 1.5C above pre-industrial levels will mean "rapid, far-reaching and unprecedented changes in all aspects of society".
It will be hugely expensive - but the window of opportunity remains open."

Clearly the summary of the report is phrased to try and get action from decision-makers and attention from media, worded by desperate, frustrated scientists.
According to the BBC report:

"The critical 33-page Summary for Policymakers certainly bears the hallmarks of difficult negotiations between climate researchers determined to stick to what their studies have shown and political representatives more concerned with economies and living standards." 

""Scientists might want to write in capital letters, 'ACT NOW, IDIOTS,' but they need to say that with facts and numbers," said Kaisa Kosonen, of Greenpeace, who was an observer at the negotiations. "And they have.""

IPCC press release.