Some environmental solutions are win-win, which help limit global warming and also protect biodiversity. But others speak of one crisis at the expense of the other. Growing trees on grasslands, for example, can destroy the plant and animal life of a rich ecosystem, even if the new trees eventually absorb carbon.
What to do?
Unless the world stops dealing with climate change and the collapse of biodiversity as separate issues, none of the problems can be addressed effectively. a report released on Thursday by researchers from two leading international scientific panels.
“These two topics are more closely intertwined than originally thought,” said Hans-Otto Pörtner, co-chair of the scientific management committee that drafted the report. They are also inextricably linked to human well-being. But global policies usually focus on one or the other, leading to unintended consequences.
“If you look at just one angle, you miss a lot of things,” said Yunne-Jai Shin, a marine biologist at the French National Research Institute for Sustainable Development and co-author of the report. ‘Every action counts. ”
How we got here
For years, one set of scientists and policymakers studied the climate crisis and tried to tackle it, warning the world about the dangers of greenhouse gases that have been building up in the atmosphere since the Industrial Revolution. The main culprit: burning of fossil fuels.
Another group studied the biodiversity crisis and tried to tackle it, sounding the alarm about extinctions and the collapse of the ecosystem. The main culprits: loss of habitat due to agriculture, and at sea, overfishing.
The two groups work largely in their own silos. But their subjects are bound by something elemental, literally: carbon itself.
The same element that makes up soot and carbon dioxide and methane heat-capture is also a fundamental building block of the natural world. It helps to form the tissues of plants and animals on earth. It is stored in forests, wetlands, grasslands and on the seabed. In fact, land and water ecosystems already emit half of human-generated emissions.
Another link between climate and biodiversity: humans have created emergencies on both fronts by using the planet’s resources in unsustainable ways.
Over the past few decades, the climate crisis has largely overshadowed the biodiversity crisis, perhaps because its threat seemed more dire. But the balance can change. Scientists warn that declining biodiversity could lead to the collapse of the ecosystem, threatening the food and water supply of mankind.
“Climate change of four or five degrees is just such an existential threat to humans, it’s hard to imagine,” said Paul Leadley, one of the authors and an ecologist at Paris-Saclay University.
And, he continued, “if we lose a great deal of the species on earth, it’s an existential threat.”
What does not work
Businesses and countries have increasingly looked to nature as a way to compensate for their emissions, for example by planting trees to absorb carbon. But science is clear: nature cannot store enough carbon to emit our greenhouse gases at our current rate.
‘A clear first priority is to reduce emissions, reduce emissions and reduce emissions, ” Dr. Pörtner said.
Just last month, the world’s leading energy agency declared that if the world wants to avoid the worst effects of global warming, nations must immediately stop approving new coal, oil and gas projects.
To make matters worse, biodiversity can destroy the measure used or proposed to address climate change.
“Some people are selling the message that if we cover the entire planet with trees, it will solve the climate problem,” said Dr. Leadley said. ‘This is a wrong message on many levels.”
In Brazil, parts of the Cerrado, a biodiverse savannah that stores large amounts of carbon, have been planted with eucalyptus and pine monocultures in an effort to achieve a global reforestation goal. The result, researchers wrote separately, is a “impending ecological disaster“because they destroy the native ecosystem and the livelihoods of local communities, including indigenous peoples.
Europe once hoped to lead the world in biofuels until it realized it was leading to deforestation and rising food prices. Another type of bioenergy, wood pellets, is currently flourishing in the southeastern United States, despite concerns about pollution and loss of biodiversity.
Climate interventions tend to harm biodiversity more than vice versa, and some compromises need to be made, the authors wrote. Solar farms, for example, eat up the habitat of wildlife, which is particularly concerned about places with endangered species. But, critically, they generate clean energy.
The report highlights ways to mitigate the damage to biodiversity, for example by grazing livestock around them, improving carbon soil supplies and avoiding intact habitat. Pollinating gardens on solar farms can help insects and birds. While wind farms can harm migratory birds, the authors note that modern turbines do much less damage.
By protecting and restoring nature, the report says, we can protect biodiversity, help reduce global warming, improve human well-being and even find protection against the effects of climate change, such as intensified floods and storms.
In the Casamance region of Senegal, for example, local communities repaired mangroves and have taken sustainable fishing measures to improve their catches, bring back dolphins and 20 fish species, store carbon and protect their shoreline, said Pamela McElwee, an environmental anthropologist at Rutgers University, one of the authors.
“Mangroves are a very special kind of ecosystem,” she said, “because they do it all for humans.”
While mangroves themselves are vulnerable to climate change, dr. McElwee said it seems less threatened than once thought, because recovery efforts work.
In the Hindu Kush Mountains of South Asia, a project has preserved an area the size of Belgium, restored forests and fields at great heights and protected endangered snow leopards and mouse deer, the report said while keeping carbon out of the atmosphere word. The 1.3 million people living there, which covers Nepal, India and the autonomous region of Tibet in China, have seen household income through tourism and sustainable farming.
Urban areas can also play their part in native trees, green spaces and coastal ecosystems, the researchers said.
The report was the first collaboration between the Intergovernmental Panel on Climate Change and the Intergovernmental Policy Policy Platform on Biodiversity and Ecosystem Services.
John P. Holdren, an environmental scientist at Harvard University and a former White House scientific adviser who was not involved in the report, calls it “a must-read for our time.”
Brad Plumer contribution made.