UN says we're going to blow past 1.5º warming, offers a "now what?" answer

In 2015, all but two countries agreed to make an effort to keep global temperatures from reaching 1.5° C above pre-industrial readings. Since then, most of the world has largely treated what they signed on to as aspirational, and one of the largest emitters (the US) has alternately withdrawn and recommitted to the agreement. Meanwhile, the planet has responded as expected to steadily rising carbon emissions and appears to be practically at the 1.5° limit.

On Wednesday, for the first time, the United Nations Environmental Programme (UNEP) acknowledged that reality, and conceded that the goal of keeping warming below 1.5° was no longer a viable one. Instead, its new goalposts focus on keeping both how long we exceed that limit and how much we exceed it by, at a minimum. Doing that will require both dramatic emissions cuts now and the removal of hundreds of gigatonnes of carbon dioxide from the atmosphere before the century is out.

Bowing to the inevitable

Depending on which baseline you use to establish pre-industrial temperatures, as well as which reconstruction of global temperatures you rely on, the world has either gotten very close to, or already exceeded the 1.5° milestone. The current El Niño event, which appears exceptionally strong, will almost certainly mean that we've gone over it no matter which records you choose.

The UN relies on temperatures averaged over a few decades to determine where we're at, which means we have technically not gone above the limit yet. But, as temperatures seem stubbornly disinterested in dropping much even after extremely hot years, we're likely at the start of the period where the 1.5° goal is passed. So, while it's not technically too late to get on a pathway that keeps us below this, practically it's already too late.