Former climate adviser and Conservative MP Chris Skidmore has expressed concern about a "vacuum and silence" in government regarding climate change.
According to the former minister, ministers' lack of vision could allow "climate detractors" to set the agenda.
His remarks come as internal papers indicate that the government may be about to go back on its promises to fund climate change.
No. 10 is adamant that it will reach the $11 point 6 billion spending goal intended for developing countries coping with climate change.
However, according to government documents obtained by the BBC, the UK will find it difficult to meet the funding deadline of 2026.
Rishi Sunak was cited by Lord Zac Goldsmith as having "apathy" regarding climate change in his resignation letter last week.
When Mr. Skidmore was questioned about the resignation at a conference on net-zero policies in the heart of London, he refrained from echoing Lord Goldsmith's harsh criticism.
He did note that there was currently a vacuum and silence and that the government needed to "keep on making the case.".
Politicians, he said, must "provide a vision" for voters because "that is what is needed right now.".
"That presents a challenge because, if not, that empty space will be filled.
"Either the Labour Party will fill it with their green industrial policy, or the climate deniers and delayers, who then take over the front pages of the Telegraph and the Mail, will fill it.
"Someone else will take the reins if you're not willing to. ".
One of the most ardent supporters of net-zero policies, which ensure that the UK is not increasing the total amount of greenhouse gases in the atmosphere, is Mr. Skidmore.
He was asked to review the government's implementation of net zero last year to make sure it was "pro-growth and pro-business" by then-prime minister Liz Truss.
After voting against the government on fracking in October, Mr. Skidmore, a retiring MP, said at an Institute for Government event that he had been "fully prepared to be sacked" from his climate role.
However, Ms. Truss resigned the following day, "and I was left in post," he claimed.
Ed Miliband, Labour's shadow energy secretary, said climate change was a "great threat" but also a "great opportunity" in his speech to the same conference.
He claimed that altering the UK's energy sources would prevent the nation from being "at the mercy of the Putins of this world.". Since Russia's invasion of Ukraine last year, the UK has been attempting to reduce its reliance on Russian oil and gas.
Labour softened its commitment to invest £28 billion annually in green industries last month. If the party prevails in the upcoming general election, it promises to gradually increase investment.
Mr. Miliband claimed that his party had not yet backed away from a "significant sum."
