Boris Johnson is under increasing pressure to appoint a new president of the UN climate summit, with Michael Gove emerging as the most hotly tipped choice in Westminster, as experts warned the continuing power vacuum was damaging the prospect of success at the talks.

Gove has a strong reputation among environmental campaigners, having impressed them with his energy as environment secretary under Theresa May, when he drew up a 25-year environment plan and new environment and agriculture bills.

Another potential candidate is Michael Howard, the former Tory leader and ex-environment secretary, who has taken a more active role in recent years defending the need for strong action on the climate.

The prime minister has few choices available, as two candidates – the former prime minister David Cameron and the former Tory party leader William Hague – have ruled themselves out. It is thought unlikely Johnson would reach across party lines to a Labour grandee, such as Gordon Brown, or David Miliband – a former environment secretary – or across Brexit lines to remainer candidates, such as the former Tory prime minister John Major or Lord Deben a former Tory environment secretary.

That leaves a narrowing field, and though a serving minister will carry governmental authority, the time commitment is likely to rule out sharing it with another major role, such as trade talks. The bookmaker Ladbrokes said it was offering 5-1 on Gove, with Zac Goldsmith – also a prominent environmentalist – ahead at 3-1, and Andrea Leadsom at 10-1.

Cameron and Hague are understood to have cited other commitments and concerns over the role when they turned down approaches to take on the presidency, which was left vacant by the abrupt sacking of the former energy minister Claire O’Neill last Friday.

That decision, without a replacement waiting in the wings, has left a yawning gap over several days which O’Neill has filled with bitter attacks on the government’s record, and Johnson’s character, while a further damaging row blew up over the Scottish government’s arrangements at the proposed venue in Glasgow.

Q&A What is Cop – and how will it help? Show For almost three decades, world governments have met every year to forge a global response to the climate emergency. Under the 1992 United Nations Framework Convention on Climate Change, every country on earth is treaty-bound to “avoid dangerous climate change”, and find ways to reduce greenhouse gas emissions globally in an equitable way. Cop stands for conference of the parties under the UNFCCC. The UK will host Cop26 this November in Glasgow. In the Paris agreement of 2015, all governments agreed for the first time to limit global heating to no more than 2C above pre-industrial levels, and set out non-binding national targets on greenhouse gases to achieve that. However, these targets are insufficient, and if allowed to stand would lead to an estimated 3C of heating, which scientists say would spell disaster. For that reason, the Cop26 talks in Glasgow are viewed as the last chance for global cooperation on the emergency, with countries expected to come with tough new targets on emissions. The negotiations will be led by environment ministers and civil servants, aided by UN officials. Nearly every country is expected to send a voting representative at the level of environment secretary or equivalent, and the big economies will have extensive delegations.

Each of the 196 nations on earth, bar a few failed states, is a signatory to the UNFCCC foundation treaty. The Cops, for all their flaws, are the only forum on the climate crisis in which the opinions and concerns of the poorest country carry equal weight to that of the biggest economies, such as the US and China. Agreement can only come by consensus, which gives Cop decisions global authority. Fiona Harvey Environment correspondent

Chris Stark, the chief executive of the Committee on Climate Change, , the government’s statutory adviser, tweeted: “I think I speak for most friendly independent climate advisory bodies when I say I’d like to see this COP 26 business sorted out sharpish. It’s very important that the UK is brilliant in the presidency and that Scotland is brilliant as the host for this summit.”

Doug Parr, policy director at Greenpeace UK, said: “In international diplomacy, signals do matter, and the longer the position of COP 26 president remains vacant, the weaker Britain’s authority as host will look.”

Campaigners have also pointed to the lack of a clear strategy or timetable laid out by Johnson at the launch event. One COP observer said: “You have to look serious, to inspire confidence among world leaders. We aren’t seeing them look serious.”

Representatives from developing countries said the UK could still turn around the situation, but it would require swift action before the impression took hold of a government lacking control and a coherent plan.

When the French government took on the COP presidency ahead of the Paris agreement in 2015, ministers had clear roles and a roster of events for the year was set out covering all aspects of a possible agreement, from climate science to green technology, and the delivery of finance for developing countries. Every ambassador and high-ranking officials in French embassies around the world were given instructions to bring up climate change at every possible meeting.

At the UK launch, apart from a new logo for a “year of climate action”, there was no detail on how COP 26 would be managed. The only events mentioned, apart from the summit itself in November, were two pre-meetings for negotiators arranged by the Italian government, which has formal co-host status alongside the UK.

Johnson’s attempt to take charge of the talks himself, by joining Sir David Attenborough on stage at the Science Museum launch, also appeared to backfire. The prime minister said little of substance, preferring to talk about a 19th-century pioneer of electric taxis, and the absence of a COP 26 president was made all the more obvious.

Tom Burke, founder of the E3G environmental group, said: “The prime minister made a hash of launching COP 26, and has put a dent in the UK’s deserved reputation for climate leadership.”

Runners and riders for COP 26 president

3-1 Zac Goldsmith

A passionate environmentalist and former owner of the Ecologist magazine, Goldsmith was appointed to the Lords with a ministerial role at the Department for International Development after losing his seat in the general election.

5-1 Michael Gove

Hotly tipped within Westminster, Gove surprised green campaigners by proving an effective and reforming environment secretary, having outed himself as a “shy green Tory”. Can bank on goodwill and respect among the climate community, and has the ministerial heft and record. Also enjoys good relations with Rupert Murdoch and was described as a “phenomenon” by Donald Trump. Gove was thought to want a greater role in the negotiations on new trade deals following Brexit, but now that David Frost has taken on more of that responsibility, Gove may be willing to consider the COP 26 role.

10-1 Andrea Leadsom

A prospect viewed with horror by climate campaigners. Leadsom is reported to have asked officials whether climate change was real when taking up her previous role as energy minister.

12-1 Gordon Brown

Took on a strong role at the Copenhagen climate summit in 2009, and as a Scot would relish hosting the conference in Glasgow. But as a former Labour prime minister, the chances seem slim.

16-1 Michael Howard

Former leader of the Conservative party, and environment minister under John Major. He was instrumental in leading George HW Bush to sign the UN framework convention on climate change at Rio in 1992. In recent years he has made the case for stronger action on the climate crisis.

The long shots

Amber Rudd

The former secretary of state at the Department of Energy and Climate Change has experience of COPs and the COP process.

Lord Deben

As John Selwyn Gummer, he was a well-regarded environment minister under Margaret Thatcher. Currently chairman of the Committee on Climate Change, where he takes a robust view of the government’s need to step up its actions to deliver net zero emissions by 2050. His strongly pro-remain stance is likely to rule him out, however.

George Osborne

The former chancellor only has six – or is it nine? – jobs already, including editing the Evening Standard and advising fossil fuel investors BlackRock, which recently pledged to examine the climate impacts of its investments.

John Major

The only living ex-Tory male Tory prime minister not to have been approached (yet). Almost no chance, given his very public rows over Brexit.

The non-Tories

David Miliband

A former Labour environment secretary.

Ed Davey

A former Lib Dem energy and climate change secretary.

The non-runners

David Cameron

The former prime minister has already ruled himself out, citing a lack of time.

William Hague

The former Tory leader is believed to have turned it down.

Odds from Ladbrokes