To stop climate catastrophe, there are certain places on Earth that we simply cannot afford to destroy, according to new research by Conservation International scientists.
Compiling carbon data from forests, grasslands and wetlands, the scientists determined how much carbon is stored in ecosystems across the globe and measured how long it would take to get it back if it is lost — and what that loss would mean for humanity.
The result: A blueprint for where — and how — to focus efforts to protect Earth’s living carbon reserves.
‘A generation’s worth of carbon’
The scientists identified pockets of “irrecoverable carbon” — vast stores of carbon that are potentially vulnerable to release from human activity and, if lost, could not be restored by 2050. (Why 2050? It’s the year by which humans need to reach net-zero emissions to avoid a climate catastrophe.)
Irrecoverable carbon spans six of the seven continents, including vast stores in the Amazon, the Congo Basin, Indonesia, Northwestern North America, Southern Chile, Southeastern Australia and New Zealand. These ecosystems contain more than 260 billion tons of irrecoverable carbon, most of which is stored in mangroves, peatlands, old-growth forests and marshes. This amount of carbon is equivalent to 26 years of fossil fuel emissions at current rates.
“We are talking about a generation’s worth of carbon contained in these critical ecosystems,” explained Allie Goldstein, a climate scientist at Conservation International and the paper’s lead author. “The good news is that we now know where this irrecoverable carbon can be found — and it is largely within our control to protect it.”
Carbon is constantly flowing in and out of ecosystems, added Conservation International scientist Will Turner, also an author on the paper.
But as humans destroy city-size swaths of forests at an increasing rate, the scale is tipping heavily toward “out.”
“We already know that fossil fuels release massive amounts of emissions and that we need to keep them in the ground,” Turner said. “We now know that when particular ecosystems are destroyed or degraded, they release massive amounts of carbon that we simply can’t get back in time to avoid the most dangerous impacts of climate change. We have to make protecting these places a top priority of this decade.”
In the paper, scientists analyzed the carbon stocks stored across the world’s major ecosystems through three dimensions: whether humans can influence that stock of carbon, the amount of carbon likely to be released if the ecosystem was disturbed or converted, and how quickly the stock could be recovered if lost.
With these criteria, the researchers were able to pinpoint which ecosystems are most crucial to prioritize for climate action — and where humans can actually have an impact.
“There are some carbon stocks in ecosystems such as tundra, where permafrost will release carbon as it thaws due to global warming itself,” Turner said. “Unfortunately, at this point there is little we can do directly in those places to keep the carbon from releasing. But other carbon stocks that we studied are being released due to human activities such as clearing forests — which means that humans can also make a difference by protecting them.”
Driven by agriculture and logging, tropical deforestation rates have soared across the globe. In the Amazon, the world’s largest rainforest, forest destruction has surged a staggering 85 percent since 2018. Mangroves continue to be destroyed, with more than 100,000 hectares (247,000 acres) lost from 2000 to 2012. Peatlands are suffering a similar fate, drained and cleared, mostly to make room for oil palm plantations.
We’ve still got time
According to Goldstein, however, there is still time to protect these critical ecosystems.
“We are right in the sweet spot of where the carbon stocks in most of these ecosystems are still manageable,” Goldstein said. “Our land-use decisions still matter right now. If temperatures increase by more than 2 degrees Celsius, then there will be more ecosystems that are going to shift into that unmanageable category.”
Although not every ecosystem that stores irrecoverable carbon is under threat at the moment, past does not always equal future when it comes to risk, Turner says.
Take Borneo: A few decades ago, the island was filled with peatlands and forests teeming with wildlife, he explained. Now, Borneo has a staggeringly high rate of deforestation, with more than a quarter million hectares of old-growth forests and peat destroyed every year, much of it converted to oil palm plantations.
As agricultural production and development intensify across the globe, countries must act both reactively and proactively to protect these crucial ecosystems, Turner advised.
“Preventing deforestation only in places where it is happening right now is like having a health-care system made up only of emergency rooms. We need to be proactive about protecting these living carbon reserves while we still can.”
Protect nature, protect carbon
The bad news: If we lose a third of this irrecoverable carbon, that alone would put us over our carbon budget to stay within a 1.5-degree Celsius (2.7 degrees Fahrenheit) temperature rise —the limit that scientists say is necessary to prevent the worst impacts of climate change.
The good news: There are a number of activities that humans can do to protect it, says Bronson Griscom, who leads Conservation International’s work on natural climate solutions and was also a co-author of the new study.
To stop climate breakdown, he explained, we need to do two things: emit less carbon and remove excess carbon from the atmosphere.
“Irrecoverable carbon stocks are an essential piece of the natural climate solutions story,” Griscom said.“We need to start designing the next generation of protected area networks that span across a number of these critical ecosystems with high irrecoverable carbon stocks, and prioritize protection for the ones that are most at risk. These ecosystems are not only critical for our climate, they are also hotspots for other essential ecosystem services like flood control, water filtration and biodiversity.”
Next step: a ‘treasure map’
Now that these scientists know which ecosystems hold the most irrecoverable carbon, they are determining where exactly they can be found.
“By locating irrecoverable carbon stocks at a global scale, we can provide countries with a treasure map of the places we can least afford to lose and the places where we have to halt deforestation the fastest,” explained Goldstein.
“This will help us actually plan irrecoverable carbon protection and where to allocate funding at the local, national and global scale.”
What sets this map apart: It will show how much irrecoverable carbon is in existing protected areas and under indigenous management, and where — as well as the pockets that are currently unprotected.
Conservation International is also using this research to undertake an ambitious initiative to protect tens of millions of hectares of ecosystems high in irrecoverable carbon.
But to avoid the most severe impacts of climate change, protecting irrecoverable carbon must be a priority across industries and stakeholders — from the private sector to governments.
“We have growing evidence that the final battle ground whether we fail or succeed in delivering the Paris Climate Agreement of holding the 1.5 degrees Celsius global warming line, is not only whether we are able to get off fossil fuels, it is also whether we are able to safeguard the carbon sinks in nature,” said Johan Rockström, Conservation International’s chief scientist. “Here, we provide the first global assessment of the ecosystems that hold our future in their hands.”
Cover image: Mangroves in Guyana (© Pete Oxford/iCLP)