The government has appointed the UK’s first envoy for nature, a role that a former campaigner called “the environmentalist’s environmentalist”, who will be charged with forging global agreement on halting the precipitous decline of species.

Ruth Davis, the new special representative for nature, is in Colombia for the start of two weeks of vital talks that will decide the global response to the biodiversity crisis. The UK has played a leading role in such efforts in the past and Davis helped draw up a global pledge on deforestation that was one of the main outcomes of the UN Cop26 climate summit hosted in Glasgow in 2021.

She will report to the foreign secretary, David Lammy, and the environment secretary, Steve Reed. The appointment of a nature envoy, first revealed by the Guardian, is an initial step in the government’s plan to put the UK at the centre of global efforts to stave off environmental collapse.

Davis previously held senior roles at charities including Greenpeace, the RSPB and Plantlife, and the thinktank and consultancy E3G. She has worked on environmental policy for 25 years, and is renowned for her commitment – at the Copenhagen climate conference in 2009 she was said to have slept overnight in a cupboard in the conference centre as the talks dragged on.

Reed is leading the UK’s negotiations on biodiversity in Cali, Colombia. He said: “We cannot address the nature and climate crises without coordinated global action. That is why we have appointed Ruth as our special representative for nature – a landmark first – who will champion our ambition to put climate and nature at the heart of our foreign policy.”

He added: “We depend on nature in every aspect of our lives – it underpins our economy, health and society – and yet progress to restore our wildlife and habitats has been too slow. Ruth’s extensive knowledge and expertise will be vital to help us deliver on our commitments to put nature on the road to recovery.”

Lammy has also promised to put the climate and nature protection at the heart of the UK’s foreign policy, as he views the environmental crises as threats to national security. Keir Starmer, the prime minister, has also set out his intention for the UK to lead in these areas, citing the climate in his speech to the UN general assembly last month.

“We are returning the UK to responsible global leadership,” he told fellow heads of government. “Because it is right, but also because it is plainly in our self-interest.”

Davis said: “The government has recognised that the nature crisis is of equal gravity to the climate crisis, and that we cannot tackle one without addressing the other. Ecosystems and the species they support are essential to maintain food security, reduce health risks and manage the impacts of rising global temperatures.”

Her appointment follows that of Rachel Kyte, formerly the top climate official at the World Bank, to the role of climate envoy, a post that was scrapped under the Conservative government. That appointment was criticised as Kyte also holds a position on an advisory board to a charitable foundation funded by a financial investment firm that made a £4m donation to Labour before the election.

Kyte was not involved in that decision, and many prominent environmental experts leaped to her defence. Nicholas Stern, the economist, told the Guardian: “Rachel was on the board of the philanthropic foundation and not the company, and she was very well equipped to advise that foundation. No conflict of interest.”

The Guardian understands that Davis will not hold any other external roles.

Davis beat a strong field of candidates for the new role of nature envoy. Names spoken of in relation to the post included Tanya Steele, the chief executive of WWF UK; Matthew Gould, the chief executive of the Zoological Society of London; and Tony Juniper, the chair of Natural England.

Leading voices in green campaigning hailed Davis’s appointment. Edward Davey, the head of the UK office of the World Resources Institute thinktank, said: “Ruth Davis is the environmentalist’s environmentalist, and the best of us: profoundly knowledgeable, deeply committed, a person of fearless integrity, and entirely selfless. She will be a nature envoy and is a brilliant appointment.”

Zac Goldsmith, the Conservative former minister, said: “I worked with Ruth as a minister and was always impressed by her knowledge and commitment. She will be a real asset to the new government.”

Oscar Soria, the director of the Common Initiative, a thinktank specialising in global environmental policy, said: “Ruth’s name means: a compassionate friend. The UK is now appointing a big heart and a clear mind, and that’s good news for the world.

“Her deep understanding of global contexts, paired with a diplomatic touch that bridges cultures and countries, sets her apart. In a world needing both global insight and local action, Ruth thrives in complexity. Her intelligence is matched by an often overlooked quality: compassion. At a time when the world needs thoughtful, caring leadership, Ruth is the person to guide the UK with empathy and respect, ensuring no path is left unexplored in the fight for biodiversity.”

The UN biodiversity conference Cop16 in Cali begins on Monday. At the summit, governments will examine progress towards meeting this decade’s UN targets to halt biodiversity loss, which include protecting 30% of land and sea for nature and repurposing $500bn (£380bn) of environmentally harmful subsidies.