The continued failure to sufficiently slash greenhouse gas pollution will set off irreversible “tipping point” events including four — the irreversible collapse of the Greenland and West Antarctic ice sheets, thawing of permafrost in the high northern hemisphere, and the relatively immediate loss of tropical coral reefs — that could all be set off at just 1.5°C (2.7°F) of warming above pre-industrial levels, according to research published Thursday in Science. The study assessed 16 tipping point events estimated to be set off by up more than 7°C of warming. (See this graphic from The Guardian.) Current policies will heat the Earth by a projected 2.7°C (4.9°F). “When you start tipping over backwards [in a folding chair] you have in that case a very simple kind of feedback on the forces of gravity operating on propelling you backwards until SPLAT,” Tim Lenton, an Earth systems scientist at the University of Exeter and co-author of the paper, analogized to the AP. “Let’s hope we’re not right.” While some tipping points, like permafrost melt, can incite further warning, that warming can still be limited by action to dramatically cut fossil fuel use and greenhouse gas pollution. “The study really underpins why the Paris agreement goal of 1.5°C is so important and must be fought for,” lead author David Armstrong McKay, also of the University of Exeter, told The Guardian. “There are grounds for grief, but there are also still grounds for hope. (AP, The Guardian, NPR, The Hill, Reuters, New York Times $, Bloomberg $)