Prime Minister Rishi Sunak softening the pace of Britain's net-zero agenda will make its targets harder to achieve while costing people more, his own government's climate advisers said Thursday.
Sunak announced last month that a ban on the sale of new petrol and diesel cars would be delayed from 2030 to 2035.
He also lowered the proportion of households that will be required to replace their gas boilers with a low-carbon alternative. And he scrapped a plan to make landlords improve the energy efficiency of their properties.
Sunak insisted he remains committed to net zero, but has not provided any evidence to prove the new changes are compatible with the country's targets, the independent Climate Change Committee (CCC) said.
It advises on government policy on how to reach Britain's net zero aims.
"We remain concerned about the likelihood of achieving the UK's future targets, especially the substantial policy gap to the UK's 2030 goal," said Piers Forster, a professor of climate physics and the CCC's chair.
"Around a fifth of the required emissions reductions to 2030 are covered by plans that we assess as insufficient.
"Recent policy announcements were not accompanied by estimates of their effect on future emissions, nor evidence to back the government's assurance that the UK's targets will still be met."
Forster urged Sunak's government to adopt "greater transparency in updating its analysis at the time of major announcements".
In its analysis of Sunak's announcements, the CCC warned that renters would have to pay more for energy in their less efficient houses. Drivers who move to electric cars later rather than sooner will face higher costs through their vehicle's lifetime, it added.
UK emissions are supposed to fall by 68 percent compared with 1990 levels by the end of the decade.
The 2030 target is seen as a critical step towards becoming net zero by 2050 and stopping global temperatures climbing by more than 1.5 degrees Celsius above pre-industrial levels.