Glasgow (AFP) -
Experts on Thursday cautiously welcomed a joint pact by China and the United States to accelerate climate action this decade, as COP26 negotiations edged towards their end with no clear plan to limit heating to 1.5C.
The surprise declaration unveiled late Wednesday by envoys John Kerry and Xie Zhenhua said the world's two largest emitters 'recognise the seriousness and urgency of the climate crisis'.
Importantly, the document stressed the need for carbon pollution to fall this decade and committed to work swiftly to reduce their emissions of methane -- a potent greenhouse gas.
Observers said the pact, which was short on detail, should allay fears that US-China tensions coming into the two-week UN climate summit in Glasgow might derail the talks.
'It can only be good news that the US and China are working closely on climate change and slashing methane emissions,' said Bernice Lee, research director at the Chatham House think tank.
'But the statement is not enough to close the deal. The real test of Washington and Beijing is how hard they push for a 1.5C aligned deal here in Glasgow.'
Delegates from nearly 200 countries are at the business end of negotiations aimed at keeping the Paris Agreement temperature goals within reach.
The landmark 2015 accord saw nations promise to limit heating to 'well below' two degrees Celsius and to work towards a safer 1.5C cap through sweeping emissions cuts.
But in the six years since, carbon pollution has continued to increase as stronger and more frequent extreme drought, floods and storms are linked to the 1.1C of warming humans have so far caused.
In Paris, countries agreed to redouble their emissions cutting plans every five years under the agreement's 'ratchet' mechanism designed to produce ever-growing climate ambition.
But several large emitters, China included, missed the 2020 deadline for submitting new plans, known as nationally determined contributions (NDCs). Others handed in plans that were no more ambitious -- or even less so -- than their initial plans.
The UN says that national pledges to date set Earth on course to warm 2.7C this century.
- Climate 'transcends other issues' -
Wednesday saw the release of draft 'decisions', which were the first real indication of where nations are 10 days into deeply technical discussions.
The text, which is sure to change during ministerial debates, called for nations to 'revisit and strengthen' their NDCs by next year, instead of 2025 as previously agreed.
But several issues remain unresolved. These include how vulnerable nations are supported financially to green their economies and prepare for future shocks.
Rules over transparency, common reporting of climate action and carbon markets are all also still being debated.
And nations already hit by climate disasters are demanding 'loss and damage' support from rich emitters.
But the main sticking point is ambition: which countries plan to slash their carbon emissions fast enough to avert dangerous heating.
European Commission vice president Frans Timmermans said that the US-China pact would have a 'positive influence' on discussions in Glasgow.
'With all the difficulties they have on other issues, to now actually signal this issue transcends other issues... that helps the global community come to terms with the fact that we have to act now,' he told AFP.