After the COP27 climate conference, representatives from around the world gathered in Montreal this week for the COP15 meeting dedicated to biodiversity. Scientists say leaders face a crucial challenge: agreeing on a common way forward to safeguard biodiversity by 2030 in order to preserve plant and animal life and help combat climate imbalance.
Wildlife populations have fallen by 69 percent globally in the past 50 years, the World Wildlife Fund (WWF) said in an October 2022 report. At the same time, land degradation – including deforestation, soil erosion and loss of natural areas – now affects up to 40 percent of the Earth’s land and half of humanity, according to the UN. These alarming figures are the backdrop for the COP15 conference on biodiversity that began on December 7 in Montreal with an ambitious objective: to agree a new global framework for safeguarding the natural world.
“The stakes are crucially high: we are currently living through a biodiversity crisis,” says Philippe Grandcolas, entomologist and research director at France’s National Centre for Scientific Research (CNRS). “Biodiversity is essential to human survival. It ensures that we can feed ourselves, have access to drinking water, and it plays a major role in our health. But, above all, biodiversity plays an indispensable role in the stability of the planet.”
At present, 70 percent of ecosystems around the world are in a state of degradation, largely due to human activity – a rate of decline described as “unprecedented and dangerous” by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES).
In addition, more than 1 million species are threatened with extinction. Vertebrates, which include mammals, fish, birds, reptiles and amphibians and make up five percent of all animal species, are especially under threat. “Our previous report found that there had been a 68 percent fall among the total [vertebrate] population [over 50 years],” says Pierre Cannet, director of advocacy and campaigns at WWF France. In 2022 that figure has risen to 69 percent. “Losing one percent in two years is massive. For species that already have small populations, it could mean extinction.”
Climate imbalance: A growing threat
According to the IPBES, the most significant driving factor of the ”biodiversity crisis” is change in how land is used and fragmentation of natural space, most often due to agriculture. This is followed by overfishing, hunting and poaching. There is a tie for third place between climate imbalance, pollution and invasive species.
“In the majority of cases there are multiple factors at play,” says Grandcolas. “But climate imbalance is becoming the most significant threat. The more it escalates, the more it disturbs ecosystems and has an impact on flora and fauna.”
There are plenty of examples of this impact. In the past 30 years elephant populations in African forests have fallen by 86 percent. The main causes are poaching and black market trade, causing the death of 20,000 to 30,000 elephants per year, according to the WWF. But repeated cycles of drought and flood are also having an impact on access to fresh water – a vital resource for the species as each animal consumes around 150 to 200 litres per day. Without it their survival is at risk.
Similarly, leatherback sea turtles in Suriname have seen their populations fall by 95 percent in 20 years. This is due in part to destruction of their habitat caused by human intervention and illegal fishing. But climate instability is also disrupting their reproduction rates as sea level rise has destroyed and disrupted turtle nesting beaches.
“Currently there are a few species that are classed having climate change as the reason for their extinction,” says Camille Parmesan, research director at CNRS and author of the first report of its kind on the links between climate change and biodiversity, produced by IPBES and the UN’s Intergovernmental Panel on Climate Change (IPCC) in 2021. Yet this is the reason for the demise of the Bramble Cay melomys: “a species of little rodent that lived on the small islands between Australia and Papua New Guinea. Scientists proved that their disappearance was due to their habitat being submerged [by the sea],” Parmesan says.
“We have also noted the disappearance of 92 amphibian species, killed by the growth of a type of fungus. We have proof that it developed due to climate instability which modified ecosystems and created the right conditions for it to thrive.”
The number of species that are officially classed as having died out due to climate instability may be low, but increasing extreme weather events are causing mass deaths among mammals, birds, fish and trees. “In Australia, we counted 45,000 flying fox deaths [a type of bat] in a single day during a heatwave”, Parmesan says. In France, record summer heat in 2022 caused temperatures in the Mediterranean Sea to rise to levels that killed thousands of fish and shellfish.
Yet, disappearing species is not the only consequence of climate change. “We can also add behaviour changes, notably migrations induced by climate modifications,” Parmesan adds. “Certain species try to move to [new] habitats that are more favourable but this can cause even more disruption in ecosystems.”
Biodiverse carbon storage
Shrinking biodiversity also has multiple consequences on human life. In some parts of the world it can disrupt economies reliant on fishing or hunting and negatively impact the tourism industry.
“It’s a vicious circle. Biodiversity is a victim of global warming, but it is also one of the major tools to fight against it”, says Sébastien Barot, researcher at French public research institution Institut de recherche pour le développement (IRD).
From plant life to animal species, individual elements of the natural world all contribute to regulating and supporting the environment as a whole. Bardot says, “water and earth play a role in filtering pollution, and bumblebees are essential for plant reproduction”.
But when one element is compromised the rest can suffer too. “The survival of the planet depends on a fine balance,” says Grandcolas. “Imagine a group of frogs suddenly die in a habitat. As insignificant as that may seem, it will have an impact: by disappearing they modify the conditions of the environment. This could allow other species to develop, damage plant life and lead to progressive destruction of the ecosystem, which will then no longer be able to play its role as a climate regulator.”
Nowhere is this more evident that with carbon storage. Scientists estimate that the earth and sea currently absorb almost 50 percent of C02 created by human activity. “Forests, wetlands, mangrove swamps and even deep water are real C02 sinks. When they disappear, emissions are released into the atmosphere,” Barot says.
Consequently, “when we see a forest burn, we are watching a carbon sink disappear”, says Grandcolas. In this way, “[the presence of] plant life has an obvious impact on the climate.”
Two crises, one solution?
Experts agree on the need to tackle both the climate crisis and the biodiversity crisis at the same time. “We tend to treat them as separate entities, but they go hand in hand,” says Grandcolas. “They should be seen as a joint struggle with equal importance. For this to happen, we need to give nature the space it deserves.”
Scientists and the WWF have called for more nature-based solutions for both issues. One of the most prominent is increasing protected habitats, which currently make up 17 percent of land and eight percent of ocean globally. “We need to increase that to 30-50 percent of the planet,” says Grandcolas. A significant step towards this goal, he adds, would be better global policies for fighting deforestation as preserving forests has the potential to both protect biodiversity and reduce greenhouse gas emissions.
“There are also many things to consider in terms of agriculture,” says Barot. “We need agriculture systems that are more durable such as developing agroecology and agroforestry. We can improve how cultivated land is managed and limit use of fertilizer … which would help both biodiversity and the climate.”
“Protection alone is no longer enough; 70 percent of land is now in a degraded state,” Parmesan adds. “It is essential to put stronger policies in place for restoring ecosystems. That would enable us to recreate habitats for animals and plants, and the climate benefits would follow.” For this to be successful a holistic approach is needed. “There’s no point planting trees purely to compensate for carbon emissions,” Parmesan says. “It needs to be done with respect for balance in the ecosystem. Big plantations filled with monocultures are not good for biodiversity or for the climate because they are more vulnerable to climate risks.”
The three scientists estimate that nature-based solutions could provide around a third of necessary climate mitigation measures even if other steps, such as reducing greenhouse gas emissions, must come from changes in human behaviour.
Many such solutions are up for discussion at the COP15 biodiversity conference. Even so, other issues – namely money – may dominate. Supported by 22 other countries, Brazil has requested that rich nations provide “at least $100 billion per year until 2030” to developing countries in order to finance nature protection initiatives. The request is yet to receive a response.
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