The Intergovernmental Panel on Climate Change (IPCC) reconsiders global warming in their new report published 8 Oct. 2018 and forcasts severe impacts on the world even at a 1.5°C rise in temperature: ocean rise, coastal and river flooding, droughts, food shortages and wildfires, and a mass die-off of coral reefs …

Previously the IPCC had focused on a 2.0°C temperature rise, considered to be the onset of severe effects of climate change.  The most recent 2018 report underlines “… that we are already seeing the consequences of 1°C of global warming through more extreme weather, rising sea levels and diminishing Arctic sea ice, among other changes” ⇒. 

However the report understates that self-reinforcing feedback loops*, which exist but are incompletely understood,  accelerate effects of climate change and could throw the world into chaos prematurely.

See reports by the New York Times, The Guardian, news.com.au. 

*:  An exampe of a feedback loop is that ice packs are white and reflect heat, so when they melt and expose dark sea or land, heat is absorbed and warming increases