Nature itself has already saved humanity from a climate cataclysm, new research finds.
Published today, the study found that without Earth’s complex web of terrestrial and marine ecosystems — known as the biosphere — we would already be seeing far more severe climate impacts than we are now.
Using a state-of-the-art computer model of Earth, the study’s authors — including Conservation International scientists Dave Hole, Johan Rockström, Bronson Griscom and Michael Mascia — simulated how ecosystems, such as mangroves and old-growth forests, absorb and store climate-warming carbon. They then demonstrated how global temperatures would have risen if humanity had gone through the Industrial Age with a biosphere that did not actively absorb carbon pollution. The results were stark.
“Without nature’s helping hand, the world would be on track to hit 3 degrees Celsius (5.4 degrees Fahrenheit) of warming by the end of the century — even if we drastically cut all other carbon emissions across our economies,” Hole said. “This study offers a much clearer understanding of how big a role nature plays in stashing away carbon and stabilizing the climate.”
And humanity needs all the help it can get, according to a recent UN report. Global warming will almost certainly surpass 1.5 degrees Celsius (2.7 degrees Fahrenheit) within the next 20 years unless countries act more quickly to reduce greenhouse gas emissions and protect nature on a much larger scale, the report found.
“Troublingly, the biosphere’s natural balance is slowly succumbing to human pressures and climate change impacts,” said Rockström, chief scientist at Conservation International and director of the Potsdam Institute for Climate Impact Research.
“Humanity needs to act now — as stewards of nature — to restore and protect the vast ecosystems that halve our carbon emissions each year. Otherwise, we will not meet the critical benchmarks for the coming decade, as outlined in the Paris Agreement.”
What to do? Protect, manage, restore
World leaders are set to convene early next year at a series of environmental negotiations, where they will submit new climate goals under the Paris Agreement. But just as important as the goals are the ways in which countries will achieve them, Hole says.
“We already have the tools we need to prevent a climate crisis — and nature provides many of them,” he said. “But governments, businesses and individuals need to act globally to protect and expand these ecosystems, which are absolutely critical to maintaining life as we know it.”
The new study found that the large-scale protection, restoration and sustainable management of Earth’s ecosystems could reduce warming by 0.3 degrees Celsius (0.54 degrees Fahrenheit) by the end of the century. When it comes to limiting the negative impacts of climate change, even a fraction of a degree matters.
So what is it going to take to avoid catastrophic climate change — and for humans to become active stewards of Earth’s biosphere? According to the researchers, there are three key steps: halving emissions each decade to achieve carbon neutrality by 2050, transforming agriculture and forestry so these industries absorb more greenhouse gases than they emit, and restoring and expanding carbon-rich ecosystems such as old-growth forests.
Conservation International experts are currently working to create a roadmap to help determine “who” — from farmers to foresters to consumers — must be empowered to do “what” and “where” to ensure nature can continue to limit global warming. One key aspect of the roadmap is protecting the world’s “irrecoverable carbon” — that is, vast stores of carbon that, if lost, could not be restored by 2050. Mostly locked away in mangroves, peatlands, forests and marshes, this carbon is equivalent to 15 times the global fossil fuel emissions released in 2020.
“We can’t afford to lose the carbon stored in these ecosystems,” Hole said. “To conserve nature effectively, we need all hands on deck — the public and private sectors and the people whose lives are intertwined with nature. We have just a small window of time remaining to take decisive action to protect the biosphere, which has protected us for so long.”
