On biodiversity day at the Cop27 climate conference in Egypt, Christiana Figueres, Laurence Tubiana, Laurent Fabius and Manuel Pulgar-Vidal, who helped design the Paris agreement, said Cop15 would be an “unprecedented” opportunity to reverse the tide in the loss of nature. It follows scientific warnings that humans are driving the sixth mass extinction of life on Earth, with 1 million species at risk of extinction. The biodiversity summit is being held in Montreal, Canada, just two weeks after Cop27 in Egypt, where governments will negotiate this decade’s goals to prevent biodiversity loss. Despite ominous scientific warnings about the health of the planet and the consequences for human civilization, no world leaders are scheduled to attend the meeting, which conflicts with the soccer World Cup in Qatar. In a separate statement, a group of nearly 350 scientists, indigenous peoples, businesses and NGOs urged presidents and prime ministers to prioritize the nature summit. “Leaders must secure a global agreement on biodiversity that is as ambitious, science-based and comprehensive as the Paris Agreement on climate change. Like the Paris Agreement, it must encourage countries to commit and also step up their action according to the scale of the challenge,” said the joint statement by the planners of the Paris climate agreement. “There is no way to limit global warming to 1.5C without action to protect and restore nature. Only if we take urgent action to halt and reverse the loss of nature this decade, while continuing to step up efforts to rapidly decarbonize our economies, can we hope to achieve the promise of the Paris Agreement.” refers. “It must be inclusive, rights-based and work for everyone. And it must deliver, through the whole of society, immediate action on the ground – our future depends on it,” he continues. Figueres, Tubiana, Fabius and Pulgar-Vidal said humanity’s “accelerating destruction of nature is undermining its capacity to provide critical services, including climate change mitigation and adaptation. As with climate change, it is the most vulnerable communities that bear the greatest impacts of biodiversity loss, from loss of food security and livelihoods to reduced climate resilience. The climate and nature agendas are intertwined.” On Tuesday, ministers from about 30 countries met in Sharm el-Sheikh at a side event co-hosted by Canada and China to discuss the draft nature deal, officially known as the post-2020 biodiversity framework. The governments discussed points persistence in the negotiations, including financial support for the agreement. At Cop15, China oversees a major UN deal for the first time and holds the presidency, although its leaders have played a modest role so far, prompting fears that the biodiversity summit could be the ‘Copenhagen moment’ of nature, a reference to the conference where climate talks collapsed in 2009. Cop15 was moved from China to Canada after several pandemic-related delays and world leaders from Beijing were not invited, amid fears they were trying to downplay the event so as not to embarrass Xi Jinping, who is not expected to attend. Helena Gualinga, an indigenous Kichwa youth climate leader from Sarayaku, Ecuador, said Cop15 was a “once-in-a-decade opportunity to agree a global deal on nature” and leaders should attend and make an ambitious final agreement. “The nature and future of the climate is at stake and we will not be safe until leaders are held accountable. For generations, my community has coexisted with nature while mining and deforestation of our lands destroys wildlife, nature and people. Our existence is our resistance, when we defend the rights of our indigenous people we protect key ecosystems for the planet. We only have this decade to turn things around, yet governments are failing in their responsibilities. Cop15 in Montreal is a once-in-a-decade opportunity to agree on a global deal on nature and we need leaders to show up and deliver,” he said. Johan Rockström, director of the Potsdam Institute for Climate Impact Research, one of those in civil society urging world leaders to take Cop15 seriously, said nature is vital to keeping global warming within 1.5 C from pre-industrial levels. “To have a 50% chance of achieving 1.5 degrees Celsius and thus limit the risks of a marginal price, global greenhouse gas emissions must be halved by 2030 and reach net zero by 2050,” he said. “Critically, these pathways rely on nature’s continued ability to act as a carbon sink and buffer against the worst effects of climate change – 1.5C is not a target, it is a biophysical limit. Nature is one of the best climate solutions to stay within this limit. An ambitious global biodiversity framework at Cop15 that addresses the root causes of the decline of global commons is urgent and necessary.” Find more coverage of Age of Extinction here and follow Guardian biodiversity reporters Phoebe Weston and Patrick Greenfield on Twitter for all the latest news and features