ANTALYA, Nov 15: For a decade, the 1.5C goal has served as the north star of climate action, a line nations pledged to hold to avoid the worst ravages of a warming planet.
But at this year's global climate conference -- the first since the United Nations said the 1.5C threshold would be missed -- nations appear unsure how to take the news.
The world has already warmed about 1.4C above pre-industrial times and the UN declared in September that crossing 1.5C -- the most ambitious target threshold of the Paris accord -- was imminent and unavoidable.
Yet in Turkey, where the COP31 negotiations are at the midway point, some nations are clinging to the goal, particularly those on the frontlines of the climate crisis.
Palau President Surangel Whipps Jr, whose Pacific island nation is threatened by rising seas, said 1.5C was not "an abstract target".
"It is an existential threat to our food, our economies and sovereignty," he told world leaders in Antalya.
Some countries want a final deal at COP31 to affirm that 1.5C remains the "right goal", according to a summary of negotiating positions released by Australia, which is chairing the talks.
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There's also a push for language about returning to 1.5C "as soon as possible" and that global temperatures are "still able" to be lowered once exceeding the threshold.
In private, some negotiators are sceptical but reluctant to abandon a target seen as essential to driving the fastest possible cuts in planet-heating greenhouse gas emissions.
- Backwards step -
Others are spying an opportunity to jettison 1.5C, several observers of the ongoing closed-door climate negotiations told AFP.
This includes the Arab Group and Like-Minded Developing Countries, these sources said -- two negotiating blocs of emerging economies including Saudi Arabia and India.
One senior delegate from a western nation warned of a "potential backsliding" in climate action should those efforts succeed at COP31.
Jasper Inventor, head of Greenpeace's delegation in Antalya, said some developing nations worried "a stronger reference" to 1.5C could mean greater pressure to cut emissions without extra financial help.
Among the wish-list of negotiating priorities released on Thursday, some nations also urged a rejection of "grey literature" -- an oblique reference seen as a possible swipe at the UN Environment Programme (UNEP).
In September, UNEP published a first-of-its-kind study into "overshoot" scenarios, exploring how the world might possibly bring global temperatures back down to 1.5C by 2100 once the threshold is breached.
At COP31, outgoing UN chief Antonio Guterres -- who spent his decade in office rallying nations behind 1.5C -- said any overshoot must be "as small as possible for as short a time as possible".
- 'Extremely ambitious' -
Under the Paris agreement, nearly 200 nations agreed to keep warming "well below" 2C while pursuing efforts to limit it to 1.5C.
But as scientific evidence mounted in the years after the accord, the lower threshold took on ever greater urgency.
Beyond 1.5C, scientists say, the risks of global warming rise sharply -- from more severe floods and heatwaves to irreversible changes to the planet like the permanent loss of coral reefs.
But the idea that warming can be reversed to 1.5C is uncertain, said Pierre Friedlingstein, a climate scientist from the University of Exeter and lead author of the benchmark Global Carbon Budget study.
To get there, emissions must fall rapidly while carbon is removed from the atmosphere through natural means -- such as planting trees and restoring wetlands -- or emerging technologies.
"A massive roll-out of these new technologies" would be required at enormous scale over decades, Friedlingstein told AFP.
"It is not something I would call utopian but it is certainly extremely ambitious," he said.
