Governments hoping for a global agreement to halt biodiversity loss must put more effort into access to Covid-19 vaccines for developing countries, the UN’s biodiversity chief has warned.

Elizabeth Maruma Mrema, executive secretary of the UN Convention on Biological Diversity, said the Kunming Cop15 summit, at which governments will try to forge a “Paris agreement for nature”, was vital for halting the global crisis of species loss.

Arrangements are being made to enable all delegates to be vaccinated in good time for the in-person part of the conference in April next year. But by that stage there must also be a clear plan for making vaccines available to the populations of developing countries, said Mrema.

“If we are to continue with negotiations, ensuring that no one is left behind, it means parties can’t meet in person if the whole world is not vaccinated,” she told the Guardian. “In the developing world, vaccines are still not easily available to the rest of the population, and that’s a challenge and a worry. We need to vaccinate more broadly, not just for delegates. Otherwise the principle of leaving no one behind will be the opposite – we will have left many behind.”

The summit – the 15th conference of the parties to the 1992 UN Convention on Biological Diversity – was originally slated for October 2020 in the Chinese city of Kunming, but has been delayed three times because of the pandemic. It will now take place in two parts. The first two-week meeting will start on 11 October, hosted from Kunming but with most delegates attending virtually, and the second in-person part of the meeting will follow in April next year.

Mrema said the partition was necessary to allow for progress to be made on the discussions this year, but face-to-face negotiations were needed to seal the deal. “We need to see everyone face-to-face to negotiate,” she said. “It is difficult to negotiate virtually.”

At the meeting, countries are expected to set out a new global plan for halting the rapid decline in the world’s plant and animal species, including protecting 30% of the Earth’s land and sea, eliminating plastic pollution, and reducing pesticide use by two-thirds. Mrema said she was hopeful that a new 10-year plan would be signed with 21 targets on issues from stemming the loss of species to restoring degraded habitats that would “change our activities from nature negative to nature positive”.

“We are the culprits on biodiversity loss, we are responsible and we have to change our actions to make a difference,” she said.

She said the delay to the conference had not meant a pause in the work to tackle biodiversity loss. “Recent pledges and commitments, including by the G7, demonstrate that countries are not waiting for next year,” she said. “Actions are already taking place, we are not waiting for the framework to be adopted.”

Mrema is also hoping to get more businesses involved in reducing their impact on nature, which she regards as a crucial plank of any agreement. She pointed to the Taskforce on Nature-Related Financial Disclosures, which is now supported by more than 100 companies.

Taking as its model the separate Taskforce on Climate-Related Financial Disclosures, which has produced guidelines on how businesses can track their exposure to climate-related risks, the taskforce is working to establish a reporting framework by which businesses will be assessed on the impact they have on the natural world, and the risks they face from the destruction of nature, with the aim of reducing their negative impact.

The framework should be published in 2023. “In the beginning, it will be voluntary [for businesses to take part], but I hope it will be mandatory in future,” said Mrema. “We need businesses to become nature-positive, instead of negative in their impact on nature.”

With at least half of the world’s prosperity dependent directly on nature and the planet’s life-support systems, the economic opportunities arising from protecting nature were also huge, she argued. Stopping the destruction of – and restoring – natural ecosystems could create 350m jobs by 2030 and generate a $10tn (GBP7.5tn) increase in wealth, she said.

She called on governments to take a “whole society and a whole government approach” to biodiversity. Only by recognising the links between health, the environment, natural resources, nature, agriculture and industrial production, consumption and waste could countries break out of a cycle of degradation of land, water and nature that was driving down our capacity for prosperity and wellbeing in the future, she said.

A key part of this would be to end the harmful subsidies for agriculture, fishing and other industries that were driving species loss in many regions, she added.

Mrema, who spoke to the Guardian in quarantine in a hotel in China ahead of the opening of the virtual summit, said she would not attend the Cop26 climate summit in Glasgow this November, but that the issues of climate and biodiversity were closely linked. “It’s very important that the biodiversity community and the climate community speak to each other,” she noted. “We can’t solve the climate crisis without solving the loss of biodiversity, and we can’t solve biodiversity loss without dealing with the climate crisis.”

The UK hosts of Cop26 had hoped that the original choreography of the summits, with China hosting on biodiversity first and the climate summit to follow weeks later, would encourage an atmosphere of mutual support between the hosts and result in stronger agreements on both issues.

However, the delays owing to Covid and a series of diplomatic setbacks seem to have upset such hopes. Beijing has yet to come up with plans for Chinese emissions cuts this decade, and it is not yet known whether president Xi Jinping will attend the Cop26 summit.