Sadiq Khan said he was hoping to learn new ideas on tackling climate change as he began a three-day visit to Argentina on Wednesday.
The mayor is chairing the C40 summit of 96 world city leaders in Buenos Aires after taking a 7,000-mile overnight flight from London.
He has been criticised by Tory rivals for the amount of emissions the return trip will generate – though City Hall says it has “offset” the harm by buying sustainable aviation fuel to be used in other flights.
Mr Khan, who was appointed chair of C40 last November, said he hoped the gathering of mayors could achieve more than national leaders would manage when they meet next month in Sharm El Sheikh, Egypt, for COP27.
He told the Standard prior to setting off: “We have the largest number of mayors going to this summit, the largest number of businesses, scientists, experts, civic societies.
“What I’m hoping to do is make announcements over the next two days in relation to finance, jobs, how we show we are the doers not the delayers.”
Asked if the conference was likely to benefit Londoners, he said: “I hope so. If, for example, another city has got a great idea, let’s steal the idea, not reinvent the wheel, whether it comes to retro-fitting, green finance, electric buses or toxic air.”
The mayors of Paris, New York, Los Angeles and Athens are among those taking part. Some cities are due to be awarded cash for projects to tackle toxic air and increase the number of jobs in the “green economy”. A wider commitment to move away from fossil fuels is also expected.
Mr Khan, who will take part in 17 meetings, tweeted on Wednesday morning: “We simply cannot be accomplices to our own destruction. We cannot be destroyers of our world. No to more fossil fuel investment. No to more fossil fuel subsidies. No to more fossil fuel exploration.”
Kicking off the C40 Summit, our message is clear: we simply cannot be accomplices to our own destruction. We cannot be destroyers of our world.
— Mayor of London, Sadiq Khan (@MayorofLondon) October 19, 2022
No to more fossil fuel investment.
No to more fossil fuel subsidies.
No to more fossil fuel exploration.
#UnitedInAction
He said: “Here is the problem - our cities contribute more than 70 per cent of our carbon emissions around the globe. If we want to be tackling climate change we’ve got to be showing leadership.
“All of my meetings normally as C40 chair take place virtually. A summit in Copenhagen I attended virtually. But some of the diplomacy and negotiations you have got to do face-to-face.”
City Hall said the cost of the flights and accommodation was being paid by C40. Mr Khan is accompanied by Shirley Rodrigues, his deputy mayor for the environment, and a “skeleton staff”. They are due to return on Saturday. Buenos Aires was chosen as a location by the previous C40 chair.
The campaign group Flight Free UK, which says that a single flight can wipe out other gains from following a “sustainable” lifestyle, said the trip would generate around three tons of carbon dioxide per passenger.
Tony Devenish, GLA Conservatives environment spokesperson, said Mr Khan’s own policies, such as the expansion of the ultra-low emission zone, would do little to improve air quality.
He said: “Londoners will be wondering which is heavier: the 23.1 tons of CO2 Sadiq Khan and his team will emit on the flight, or the hot air he will put out when he gives his inane speech. Hasn’t he heard of Zoom?”