Biological diversity — or — is the variety of life on Earth, in all its forms, from genes and bacteria to entire ecosystems such as forests or coral reefs. The biodiversity we see today is the result of 4.5 billion years of evolution, increasingly influenced by humans.
Biodiversity forms the web of life that we depend on for so many things – food, water, medicine, a stable climate, economic growth, among others. Over is dependent on nature. More than 1 billion people rely on forests for their livelihoods. And land and the ocean absorb more than half of all carbon emissions.
But nature is in crisis. Up to are threatened with extinction, many within decades. Irreplaceable ecosystems like parts of the are turning from carbon sinks into carbon sources due to deforestation. And 85 per cent of , such as salt marshes and mangrove swamps which absorb large amounts of carbon, have disappeared.
How is climate change affecting biodiversity?
The main driver of biodiversity loss remains humans’ – primarily for . Human activity has already altered over 70 per cent of all ice-free land. When land is converted for agriculture, some animal and plant species may lose their habitat and face extinction.
But climate change is playing an increasingly important role in the decline of biodiversity. Climate change has altered marine, terrestrial, and freshwater ecosystems around the world. It has caused the loss of local species, increased diseases, and driven mass mortality of plants and animals, resulting in the first climate-driven extinctions.
On land, higher temperatures have forced animals and plants to move to higher elevations or higher latitudes, many moving towards the Earth’s poles, with far-reaching consequences for ecosystems. The increases with every degree of warming.
In the ocean, rising temperatures increase the . For instance, from the world’s coral reefs was lost between 2009 and 2018, mostly due to climate change, and further warming threatens to destroy almost all remaining reefs.
Overall, climate change affects the , influencing shifts in the distribution of plants, viruses, animals, and even human settlements. This can create increased opportunities for animals to and for viruses to spill over to humans. Human health can also be affected by reduced ecosystem services, such as the loss of food, medicine and livelihoods provided by nature.
Why is biodiversity essential for limiting climate change?
When human activities produce greenhouse gases, around half of the emissions remain in the atmosphere, while the other half is . These ecosystems – and the biodiversity they contain – are natural carbon sinks, providing so-called nature-based solutions to climate change.
Protecting, managing, and restoring , for example, offers roughly two-thirds of the total mitigation potential of all nature-based solutions. Despite massive and ongoing losses, forests still cover more than 30 per cent of the planet’s land.
– wetlands such as marshes and swamps – cover only 3 per cent of the world’s land, but they store twice as much carbon as all the forests. Preserving and restoring peatlands means keeping them wet so the carbon doesn’t oxidize and float off into the atmosphere.
Ocean habitats such as can also at rates up to four times higher than terrestrial forests can. Their ability to capture and store carbon make mangroves highly valuable in the fight against climate change.
, both on land and in the water, is essential for limiting carbon emissions and adapting to an already changing climate. About in the next decade could be achieved by improving nature’s ability to absorb emissions.
Is the UN tackling climate and biodiversity together?
Climate change and biodiversity loss (as well as pollution) are part of an interlinked the world is facing today. They if we are to advance the Sustainable Development Goals and secure a viable future on this planet.
Governments deal with climate change and biodiversity through two different international agreements – the (UNFCCC) and the (CBD), both established at the 1992 Rio Earth Summit.
Similar to the historic Paris Agreement made in 2015 under the UNFCCC, parties to the Biodiversity Convention in December 2022 adopted an agreement for nature, known as the , which succeeds the adopted in 2010.
The framework includes wide-ranging steps to tackle the causes of biodiversity loss worldwide, including climate change and pollution, and should .
“Delivering on the framework will contribute to the climate agenda, while full delivery of the Paris Agreement is needed to allow the framework to succeed,” said , the head of the UN Environment Programme. “We can’t work in isolation if we are to end the triple planetary crises.”
At COP15 in December 2022, , and agreed on the new framework to address biodiversity loss, restore ecosystems and protect the rights of Indigenous Peoples, who from biodiversity loss.
“Indigenous Peoples, people of African descent, and local communities are guardians of our nature,” said the UN Secretary-General. “Their traditional knowledge is a living library of biodiversity conservation. They must be protected. And they must be part of every biodiversity conversation.”
At the meeting, the parties also adopted the Multilateral Mechanism on the fair and equitable sharing of benefits arising from the use of on genetic resources.
In November 2024, at COP16 in Cali, Colombia, countries reached a historic consensus, including on the functioning of a fund, known as the Cali Fund, aimed at mobilizing new streams of funding for biodiversity action worldwide and boosting the implementation of the framework.
The Cali Fund was launched in Rome, Italy, in February 2025 on the margins of the resumed session of COP16. It is set to receive contributions from private sector entities making commercial use of data from genetic resources, with the aim to raise an additional $200 billion each year by 2030 to close the global biodiversity finance gap.
“Those profiting from nature cannot treat it like a free, infinite resource. They must step up and contribute to its protection and restoration,” the UN Secretary-General said.
Learn more
Read the UN Secretary-General’s speech at the High-Level Segment of COP16 in November 2024, and his remarks ahead of the resumed opening session of COP16 in February 2025.
Watch our interview with Elizabeth Mrema, former Executive Secretary of the United Nations Convention on Biological Diversity.
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