Boris Johnson says Cop26 will have failed unless the world has committed to “halve emissions by the end of this decade”, toughening his aims for the crucial climate summit.
Ahead of leaders gathering in Glasgow in Sunday, a Downing Street spokesman said: “This is the decade action needs to be taken – it’s no longer something that can be talked about in broad terms.”
In recent days, Mr Johnson has spoken about net zero targets for 2050 – rather than to slash carbon emissions by 2030 – prompting suggestions he was laying the ground for effective failure.
But the spokesman, asked what “success” would look like, said it must be 2030 commitments to “keep alive” the aim of preventing global temperature rises of more than 1.5C since industrialisation.
Currently, the planet is “way off track”, the United Nations has warned, on a path to 2.7C – and, experts say, 2.1C even if existing CO2-cutting commitments are kept.
Just 7.5 per cent would be chopped off predicted annual greenhouse gas emissions in 2030 – far from the 47 per cent reduction that is needed.
“We must halve emissions by the end of this decade,” the spokesman said, ahead of Mr Johnson putting G20 summit leaders in Rome, to pile on more pressure for deeper CO2 cuts.
“Countries around the world, particularly developing countries, are already seeing the real world impacts of this. They know what limiting 1.5 means in the real world, because they are seeing the impact of temperature rise – flooding, or droughts – already.”
However, the spokesman said Cop26 would not attempt to agree a specific figure for reducing expected gigatonnes of carbon dioxide emitted by 2030, insisting that was not its role.
And he declined to say whether a tougher “rachet” mechanism – to force countries to prove progress towards announced goals every two years, instead of five – would be set down.
But No 10 insisted the UK, as the Cop26 host, would not be “marking its own homework” on success or failure, when the summit concludes in two weeks’ time.
It would be up to the UN and others to judge whether the agreements reached are “sufficient that we remain on track” to a temperature rise of 1.5C.
What No 10 is calling an “extremely ambitious goal” for Glasgow comes despite gloom that China has failed to shift in its long-awaited “nationally determined contribution” (NDC).
Emissions by the world’s biggest current contributor to the climate emergency would still only peak by 2030 and be reduced to net zero only three decades later.
Mr Johnson will badger other G20 leaders to go faster and further despite the failure to boost spending on the UK’s – largely unfunded – net zero plan, in Wednesday’s Budget.
Instead, the chancellor Rishi Sunak was sharply criticised for making flying and driving cheaper, widening the divide with sky-high train fares.
Nevertheless, the spokesman said: “The success of Cop26 still hangs in the balance. Too many countries are still doing too little. It’s going to be challenging.”
Speaking on the flight to Rome, Mr Johnson called Cop26 “the last opportunity for the planet“, but also struck a more cautious note.
“We are not going to stop global warming in Rome or in this meeting in Cop” he said.
“The most we can hope to do is slow the increase. What we need to do is to take steps now that give us the ability in future to come back and make further commitments.”
In Rome – as well as meeting Emmanuel Macron, to try to calm the fierce post-Brexit fishing dispute – Mr Johnson will come under pressure to go further on vaccine donations to poor nations.
No 10 says it is on course to have handed over 30 million “surplus” doses of the Oxford-AstraZeneca jab by the end of the year – with a total of 100 million pledged by the middle of 2022.
But Gordon Brown has organised a letter, signed by 160 former world leaders and global figures, demanding an emergency military airlift of far more.
Ahead of the G20, Mr Johnson also announced £160m to build floating offshore wind ports and factories around the UK, to help hit a target of providing 1GW of energy by 2030 – nearly 9 times the current volume worldwide.
