Humanity faces a biodiversity crisis just as profound as the climate crisis, and time is just as short for the urgent transformations of society that are the only way to escape the worst risks, an authoritative global scientific panel has concluded.
"Biodiversity," the panel declared, "is declining faster than at any time in human history." A million species are on the brink.
Climate change is one of the key drivers, the report emphasized, along with land-use change, exploding consumption, pollution and the spread of invasive species. Climate's role in exacerbating the losses is accelerating.
Like an earlier comprehensive consensus report on global warming issued by the United Nations in October, this new report warns of potentially irreversible economic, social and environmental calamities if the whole world doesn't change tracks by mid-century.
The impacts would fall especially hard on the poor and in several frail regions, but no part of the planet would escape them.
Saving natural systems, the biodiversity report said, "requires urgent and concerted efforts fostering transformative change."
Because climate plays such a significant role, avoiding the collapse of ecosystems entails rapidly cutting net emissions of carbon dioxide to zero in the next few decades. And because food and agriculture contribute to emissions, provide carbon-trapping solutions, and are imperiled by inaction, the report deals extensively with the changes needed there.
This goes even beyond the complete and rapid shift from uncontrolled use of fossil fuels to clean energy that scientists say is needed to avoid unacceptable climate risks.
What's needed, this report said, is "a change to the definition of what a good quality of life entails—decoupling the idea of a good and meaningful life from ever-increasing material consumption."
The remarkable document was issued after years of work by scores of international experts who examined some 15,000 pieces of research. The conclusions were nailed down in negotiations that dragged into the weekend's wee hours and were published on Monday. The panel will publish a full 1,500-page report later this year.
Half-Degree Key to Survival for Many Ecosystems
The rising seas and increased extreme weather events of climate change—fires, floods, pestilence and drought—have already caused widespread harm to biodiversity. Since pre-industrial times, humans have caused an estimated 1 degree Celsius of warming. The impact of this temperature rise has spilled over into changes to species distribution, population dynamics and the function of ecosystems.
In remote ecosystems like the tundra or taiga and places like Greenland, previously buffered from human damages, climate change is now unavoidable. The report cites large-scale reductions in local species populations or extinctions in some cases.
Even at 1.5°C to 2°C of warming—the goals of the Paris climate agreement—the report warns that the ranges of most of the world's species on land will shrink significantly. At 2°C of warming, the report warns that 5 percent of species will be at risk of extinction. At 4.3°C—our current track of warming—that rises to 16 percent of species.
"While climate change has not been the dominant driver of biodiversity loss to date in most parts of the world, it is projected to become as or more important than the other drivers of change," said Sir Robert Watson, chair of the biodiversity panel and former chair of the UN's Intergovernmental Panel on Climate Change.
"Therefore it is essential that we address the issues of biodiversity loss and climate change together. This means we must transform the ways we produce and use energy."
The half-degree between 1.5°C and 2°C of global warming could be the key to survival for many ecosystems, including coral reefs, which are projected to shrink to 10-30 percent of historical levels at 1.5°C of warming, or just 1 percent at 2°C.
"Anything more than 1.5°C and this becomes a planet that's very hard to manage biologically because ecosystems literally will be coming apart," said Thomas Lovejoy, a senior fellow at the United Nations Foundation, who has studied biodiversity for 30 years.
To make the changes required to save biodiversity and the climate, the report doesn't just call for stronger policies and international cooperation. It urges a global revolution—a shift in the way humans consume material goods, how we value the natural world, and how we account for nature in the way we develop our businesses and economies.
"This is actually an 'aha moment' of realization that the planet works as a linked biological and physical system," Lovejoy said. "It takes it yet one step further from climate change no longer being, 'this problem is so huge what could I possibly do,' to something individuals can contribute to by planting trees and helping restore wetlands and the like."
Unsustainable Food System Driving Biodiversity Loss
The transformation of the global landscape—along with how we manage oceans and coastlines—has been the single largest driver of biodiversity loss. And this incursion into natural landscapes, especially forests, has largely been driven by the need to produce more food for a global population that has doubled in the last 50 years.
"Conversions of native habitat, especially forest and grasslands, into agricultural systems have been needed to feed the world," Watson said. "The challenge now is, how we transform our agricultural practices, which are mainly unsustainable today, to ones that produce the food we need while protecting and conserving biodiversity."
Watson said agricultural producers have to stop expanding into natural habitat, use fewer chemicals and embrace agroecology—a system of agriculture that uses a range of crops and practices, rather than the monocultural systems that have proliferated in the last 50 years.
Echoing recent studies, Watson also stressed that dietary choices have a huge impact. The food system produces roughly 25 percent of greenhouse gas emissions, mostly linked to the raising of livestock for meat and dairy products.
"As individuals, we need to reduce food waste, excessive use of energy and water, especially in high-income countries," he said. "But we also need to consider our choices of diet, which have a profound implication on our health and the environment."
Roughly one-third of the world's land surface and three-quarters of its fresh water are now devoted to crop or livestock production, the report notes. At the same time, land degradation, in large part from food production, has meant that nearly a quarter of the world's land is less productive than it once was.
As agricultural production has boomed in the last 50 years, agricultural systems have become oversimplified toward the production of fewer crops and species. "This loss of diversity, including genetic diversity, poses a serious risk to global food security by undermining the resilience of many agricultural systems to threats such as pests, pathogens and climate change," the report said.
At the same time, agricultural producers have the ability to farm in ways that are not only more sustainable, but can stash carbon in the soil.
"Synergies also exist, such as sustainable agricultural practices that enhance soil quality, thereby improving productivity and other ecosystem functions and services such as carbon sequestration and water quality regulation," the report said.
The report notes that economic policies and subsidies have propelled unsustainable practices across fisheries and agriculture, including the expansion of cropland for biofuels.
"We need to address the root causes, with profound changes in aligning our governance systems, incorporating responsibility in our economic systems in a way that accounts for the whole chain, from production to consumption," said Eduardo Brondizio, one of the panel's co-chairs. "We need positive incentives to move away from the harmful subsidies that many times are paying for the destruction we're observing."
"We need to change our narratives," he said.