A tighter limit on global warming from 2°C above the pre industrial average to 1.5ºC higher could as much as halve the global population exposed to climate-change-induced increases in water stress according to the Intergovernmental Panel on Climate Change (IPCC).
The National Infrastructure Commission (NIC) responded to the IPCC report saying it highlighted the "need for urgent action to prevent the worst from happening." It held up its recent recommendations to government in its National Infrastructure Assessment for greater intensity in measures to curb climate change: “These recommendations have been put to Government and we look forward to hearing how they plan to put them into practice.”
In a summary of its findings for policymakers the IPCC reported that a 1.5°C ceiling would result in significantly less detriment than a 2°C limit. It warns, for example, that coral reefs, are projected to decline by a further 70–90% at 1.5°C with losses of greater than 99% at 2ºC.
The IPCC research behind the report followed from the international Paris Agreement on climate change which recommended that its parties “pursue efforts to limit the temperature increase even further to 1.5°C”. Critics have slated the policymakers' guide for its omission of some of the more severe political and financial impacts of global warming that are described in the full IPCC report which drew on some 6,000 research papers.