Keir Starmer's arrival at COP29, with a promise to drastically cut the UK's carbon emissions by 81%, will be a small ray of sunshine in an otherwise gloomy start to the climate talks.
The election of Donald Trump, who has vowed to drag the world's largest economy out of the negotiations, was a colossal setback for a round of talks dedicated to raising ambition - and cash - for the transition away from fossil fuels.
If that wasn't bad enough, Starmer was one of the few heads of the G20 to actually show up at the talks.
President Biden is absent - so too are the leaders of China, Brazil, Germany and France.
Starmer wants to portray the commitment to cutting emissions as a sign of his confidence the UK can be a leading economy without fossil fuels.
The prime minister's pledge reinforces the message these talks are urgently trying to send - that net zero is an opportunity for growth, not economic suicide.
But back home it's a political risk.
Getting to the 81% cut in emissions within 10 years will take a colossal and, in the short term, costly effort. One he was forced to insist would not involve his government telling people how to live their lives.
However, it will certainly involve changes to how people live.
Labour's plans for zero-carbon electricity, already ambitious, won't get us there alone.
Making homes more energy efficient and heating them without gas will be essential.
So too will fiddly things like protecting peat bogs, our uplands and reforming agriculture.
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While it might be portrayed as political excess, in truth, the government had no choice.
The 81% target is the one the Committee on Climate Change advised the government is the only way it can meet its obligations under the UK Climate Change Act introduced by the Conservatives with cross-party support.
That piece of legislation is, in turn, the one designed to ensure the UK meets the terms of the Paris Agreement that the UN climate process is committed to.
So, while they'll celebrate the prime minister's announcement at this summit for the signal it sends to other less ambitious countries - it's not seen as radical, but necessary.
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And praise for the prime minister will be limited here in Baku.
COP29 is mainly about money - and agreeing on a new financial mechanism to allow poorer countries that have yet to burn their "share" of fossil fuels to not follow the path that made countries like ours rich.
Starmer has arrived at this summit with a bold domestic commitment, but no promise of additional money for that process.
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The UK is not alone - many other rich countries aren't willing to ask their taxpayers to fork out more cash to tackle climate change.
The rest of these talks will be taken up with how that reality tallies with the spiralling cost of climate impacts in both rich and poor countries alike.