1.5 degrees Celsius target is the North Star for climate action

PARIS: In the realm of climate diplomacy, it's the little engine that could, the 80 to 1 odds Kentucky Derby winner, the low-budget multiverse fantasy that came out of nowhere to sweep the Oscars.

We are talking about the Paris Agreement goal of capping Earth's average surface temperature at 1.5 degrees Celsius above levels in the late 19th century, when burning fossil fuels began to heat up the planet.

The world has seen a crescendo of deadly and destructive extreme weather, as it barely 1.2 degrees Celsius above that threshold.

Fifteen years ago, a 1.5 degrees Celsius limit on global warming - championed by small island nations worried about sea level rise - was rejected by most scientists as unrealistic and by most countries as unnecessary.

A 2 degrees Celsius guardrail was assumed to be safe.

The 1.5 degrees Celsius target is enshrined in everything today, everywhere, at once. It has become the North Star for the UN climate talks, national climate plans and business world, even though it isn't an aspirational goal.

Even though most of the plans don't hold up very well under scrutiny, multinationals have unveiled promises and plans to be 1.5 degrees Celsius-aligned, from Apple and Facebook to Big Pharma and even Big Oil.

You can draw a straight line from 1.5 degrees Celsius to the science-base imperative to nearly halve global emissions by 2030 and achieve net zero around mid-century, so any residual carbon pollution must be offset by removals.

According to Beatrice Cointe, a sociologist at the National Centre for Scientific Research and co-author of a recent study on the history of the 1.5 C target, both of these targets are set to be affirmed in a report on six years of climate science, published on Monday by the Intergovernmental Panel on Climate Change IPCC.

How did an almost impossible target become a point of reference for climate action? She asked.