UNEP concedes a 1.5 °C overshoot and ties a return path to a 1.8 °C peak
UNEP's Limiting Overshoot report accepts that warming is set to pass 1.5 °C in the next few years and says there are no good outcomes above 1.5 °C. Debra Roberts says a return by century's end stays in reach if the peak is held to about 1.8 °C. The path needs emissions halved between now and 2035 and about 10 gigatonnes of CO2 removed each year; current emissions are about 40 gigatonnes. Inger Andersen says the 1.5 °C target remains, to be approached from above.
Science··Midday
UNEP treats a 1.5 °C overshoot as unavoidable
UNEP's Limiting Overshoot report accepts that global warming is set to pass 1.5 °C above pre-industrial levels in the next few years. UNEP now treats overshoot of that Paris Agreement 2015 goal as unavoidable and says there are no good outcomes above 1.5 °C. Inger Andersen said the 1.5 °C target remains the goal but now has to be approached from above. Debra Roberts says a return by century's end stays in reach if peak warming is held to about 1.8 °C.[1], [2]
UNEP's path asks for a 2035 halving and 10 gigatonnes a year removed
The path UNEP describes requires global emissions to be halved between now and 2035 and about 10 gigatonnes of CO2 removed from the atmosphere each year, against current emissions of about 40 gigatonnes. UNEP calls net zero emissions an essential milestone that cannot be skipped and stresses that carbon dioxide removal, including through vast new forests, must sit alongside deep cuts in fossil pollution rather than replace them. Debra Roberts said some losses will be irreversible, so returning to 1.5 °C does not mean returning to the same world. Debra Roberts also said the rules of the game are now changing.[1], [2]
ETH Zurich scientists discuss 2 degrees of adaptation and a 3 °C path
Reto Knutti of ETH Zurich, who was not involved in the report, said the carbon removal the scenario implies would have to scale up by a factor of around 100,000 and that the plan should be to adapt for at least 2 degrees. Konstantin Weber, also at ETH Zurich, noted that only two of the latest emissions scenarios prepared for climate modellers imply a return to 1.5 °C before 2150, while the current-policies scenario points to around 3 °C of warming in 2100. UNEP sees existing national policies at at least 2.3 °C of heating. UNEP says that at heating of up to 3 °C, glaciers could lose more than a quarter of their mass in 2100. UNEP writes of sea levels rising by up to 13 cm and global food production declining by up to 14 per cent in 2050.[1], [2]
