Sadiq Khan has been criticised by a mayoral rival for a "slow" rate of progress in achieving net zero carbon emissions in London.
The Labour mayor has vowed to make the capital carbon-neutral by 2030 - a full 20 years ahead of the Government’s target of reaching net zero nationally by 2050.
Statistics published by the London Datastore reveal that between 2015 and 2021, net carbon emissions fell by about a quarter across the city.
2015 was the last full year before Mr Khan took over as mayor, while 2021 is the latest year for which data on net emissions is available.
But Liberal Democrat candidate Rob Blackie argued that at this rate of progress, the mayor would only achieve net zero in London by 2038 - leaving him eight years behind his target.
City Hall sources said Mr Blackie had adopted a “simplistic approach” by attempting to draw a straight line based on emissions reduced over recent years - and that actions to achieve carbon neutrality will “increase in scale” over the coming years. They also pointed out that London's progress in cutting emissions has been faster than the country as a whole.
Mr Khan first suggested he would be setting the 2030 goal for London in 2020, enshrining it a year later in his 2021 re-election manifesto.
Mr Blackie said: “It’s big promises and little delivery as usual from the mayor. Sadiq Khan pledged to reach net carbon zero by 2030, but his progress has been so slow that we’ll be waiting close to a decade to hit the target. Time we simply don’t have.
“You would think a politician who wrote a book lecturing others [on] how to tackle the climate emergency would have his own house in order.”
He added: “If the mayor was serious about reaching net zero, he would be pulling on every lever he can - including the Lib Dem assembly members’ proposal to trial [an expansion of] Green Doctors.
“This scheme would tackle the single biggest source of emissions in the capital by helping Londoners with tailored advice on how they can most effectively reduce their domestic energy use. The mayor must back it in his budget.”
The proposal mentioned by Mr Blackie was an amendment to the latest version of Mr Khan’s draft budget for the coming year, put forward by the London Assembly’s Lib Dem group last month.
The Green Doctors scheme - which offers free advice to people looking to make their homes more energy-efficient - is currently run by a charity called Groundwork, and the Lib Dem amendment would put money towards expanding the service to reach more Londoners.
Mr Khan is now duty-bound to formally respond to the amendment when he presents his final draft budget later this month.
Responding to Mr Blackie’s comments, a spokeswoman for Mr Khan said: “The mayor is committed to his ambitious target for London to reach net zero by 2030.
“London continues to lead the UK on tackling climate change thanks to Sadiq’s green policies which include the biggest clean air zone in the world, improving electric vehicle charging infrastructure, electrifying bus and taxi fleets and ensuring that new developments meet net zero carbon standards.
“The mayor has always been clear that a collective effort is needed to reach net zero by 2030 and has repeatedly called on ministers to provide more funding and powers to mayors and local authorities.”
City Hall sources pointed out that London has progressed faster than the country as a whole in cutting greenhouse gases. Over the same six years - from 2015 to 2021 - net emissions across the UK fell only 14 per cent, compared with London’s 25 per cent reduction.
The mayor’s office believes that between half and two thirds of London’s net zero target will require Government action.
Mr Khan’s chosen ‘pathway’ to net zero involves the installation of 2.2 million heat pumps across the capital, as well as a 27 per cent reduction in car vehicle kilometres travelled in London by 2030.
The mayor has also said he would like to see a nearly 40 per cent reduction in the total heat demand of London’s buildings, requiring improvements to the insulation of over two million homes and a quarter of a million non-domestic buildings.
