±0.0 +0.5 +1.0 +1.5 +2.0 +3.0 +4.0 +5.0°C 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100 "Hot-house Earth": warming incompatible with human civilization, most of the planet becomes uninhabitable, possible population reduction to one billion. Some summers so hot that stepping outside could be lethal. High risk of food shortages. Deadly heatwaves every summer, hundreds of drowned cities, devastation of the majority of eco-systems, more tipping points are crossed, leading to intensified warming. High risk of reversing of carbon cycle triggering runaway warming spiral. Droughts and famine for billions of people, leading to chaos and wars. More extreme heatwaves, more floods, more doughts. Increased intensity and frequency of extreme weather events. Likely tropical crop yield decline and food supply instabilities. 5% chance of staying below 2.1°C ↑ 5% chance of reaching +4.9°C most likely scenario +3.2°C 2019 20th century average most likely scenario +3.2°C 