Is nature ‘failing’ to curb climate change? Not quite
Nature has been mopping up our carbon pollution for years — is it starting to give out? Not quite, two Conservation International scientists say.
The headline was ominous:
Trees and land absorbed almost no CO2 last year. Is nature’s carbon sink failing?
The article, published last week by the British newspaper The Guardian, described the kind of scenario that might keep climate scientists awake at night: Nature, which for so long has absorbed a great deal of humanity’s carbon pollution, is showing signs that it is losing its ability to continue doing so.
Pointing to preliminary research and other findings over the past year, Guardian reporter Patrick Greenfield wrote that natural ecosystems around the world — beset by drought, fires and pests, among other things — are no longer pulling in the same amounts of carbon from the atmosphere that they used to. The story further posited that a “sudden collapse” of this ability could “rapidly accelerate” global warming — that nature, in essence, is shifting from climate friend to climate foe.
The story concluded by quoting a scientist who leads Global Carbon Budget calculations, stating that, “We shouldn’t rely on natural forests to do the job.”
If true, what does this mean? Are humanity’s climate goals doomed? Is nature really no longer an important solution to climate change?
Hang on, two Conservation International experts say: While the article, they contend, is well-intentioned and raised critical and accurate warnings about the historic importance of ecosystems for mopping up human-caused carbon pollution, it seems to confuse monitoring of ecosystem carbon flows with natural climate solutions.
We sat down with scientists Will Turner and Bronson Griscom from Conservation International’s Center for Natural Climate Solutions to discuss.
Question: People are reading this article and freaking out. What’s your take-away from it?
Bronson Griscom: I think the story covers a lot of important points. But the article seems a bit confused — it conflates impacts of our actions on nature with the huge opportunities to turn this story around if we improve our relationship with nature. Past is not prologue — indeed, changing this trajectory of impacts on ecosystems is absolutely essential to stabilizing our climate, considering that ecosystems store four times more carbon than our atmosphere.
The story is about the global accounting of carbon flows, but it only tells one side of that story. Reported increases in forest fires and droughts in parts of Amazonia and other places around the world are real and profoundly concerning. Unreported are ongoing increases in forest growth rates in many other places where nature has been allowed to regrow, as well as around the world due to carbon dioxide fertilization, extended growing seasons and higher rainfall. Ours is a vast and complex planet, and these two contrasting outcomes are true at once.
Likewise, this article is both accurate in raising concerns, and inaccurate in implying there are not vast geographies where protection and restoration of ecosystems are working well. Indeed, the latest report from the Intergovernmental Panel on Climate Change finds that natural climate solutions are the largest climate mitigation sector, larger even than the energy sector.
Q: So you’re saying, it’s inapt to say, ‘Nature is not absorbing carbon anymore,’ when in fact it still can and it is, in many places.
BG: Exactly. The article conflates very different concepts of “gross” vs “net” carbon absorption. By that I mean, there are still massive removals from nature each year, so it’s inaccurate to say that nature is no longer “absorbing” carbon — but it’s true that the scale of that absorption, at least this year, is reaching parity with the scale of emissions. It is worth remembering that today about 95 percent of gross carbon flows into, and out of, the atmosphere, are controlled by nature.
In past decades these flows have been slightly imbalanced in our favor, such that on net, ecosystems absorb about half of human-caused carbon emissions, despite our impacts on ecosystems. It is concerning that this “subsidy from nature” seems to be slowing, but this certainly doesn’t mean the role of nature is any less important. On the contrary, it is a reminder how important ecosystems are to stabilizing our climate, and how important it is that we improve ecosystem stewardship.
Will Turner: It’s the same aggregation fallacy that I’d be making if I said, “The energy sector contributes to climate change, so we shouldn’t have solar panels.”
Look, there’s a lot this story got right. But the headline starts with this net-versus-gross problem. If your bank balance is treading water month to month, it doesn’t mean your paycheck is less important. And then the question at the end of the headline paints this misleading conclusion that nature is going to suddenly universally be against us.
BG: Right. You can invest in the resilience and the restoration of ecosystems and, that can be a great set of solutions, which is to say why statements in the article indicating that we can't assume forests will remove CO2 (carbon dioxide), I would argue, are deeply problematic.
We have the ability to destroy ecosystems, and we have the ability to restore and protect ecosystems; we have the ability to target ecosystems that are resilient to, or even benefiting from, climate change — and prioritize these places for protection and restoration from direct human impacts. In doing so, we will improve the resilience of other ecosystems, through positive feedback loops in both the water and carbon cycles.
Q: So what can we conclude from the article?
WT: The article does a good job of articulating how ending fossil fuels is essential, while correctly pointing out that “reaching net zero is impossible without nature.” What’s important is that both of those things are true. We absolutely need to decarbonize energy and industry, and at a breakneck pace. But we could eliminate fossil fuel emissions today and still blow past 2 degrees Celsius (3.7 Fahrenheit) and more of warming as long as trees keep falling in the Amazon, or we fail to restore ecosystems we’ve destroyed.
Look, anyone who says because we plant trees, we can skip transforming our energy system is sorely mistaken. But the alternative is not another single solution. It’s decarbonizing energy and industry, protecting and restoring ecosystems, and probably developing carbon removal tech, all together, right now.
We also need to recognize that the problem isn't the ecosystems turning against us — 100 percent of the problem here is what people are doing to ecosystems.
BG: Absolutely — the reason that carbon emissions from nature are increasing is of course not “natural,” but rather due to a variety of human impacts.
WT: So it's about stopping that. If anything, this article can magnify the importance of these solutions, rather than kind of giving up on them. There's actually a lot in here that's speaking to how important ecosystems are. The thousands of gigatons of carbon in ecosystems — and the thousands of gigatons of carbon underground in coal, oil and natural gas — must stay there. And the best way to limit their loss due to climate change in the future is to aggressively protect and restore them now. The fact is that there’s no point where it will be an effective climate strategy to abandon nature as a solution.
Q: What should people keep in mind about the future of nature’s role in regulating climate?
BG: The fact is, as we mentioned, that four times the amount of carbon that is in the atmosphere is held in ecosystems. We cannot lose that and have any viable path to a stable climate. We can think of this as a double-or-nothing bet: There is no option of ignoring nature in our quest to stabilize our shared climate. We must stop fossil fuel emissions, the largest source of carbon pollution today. We also must unlock natural climate solutions — the largest opportunity for carbon removal and storage today.
Ecosystems, by storing much more carbon than the atmosphere holds, and by having the greatest potential to remove more carbon from the atmosphere, present both a huge risk and a huge opportunity. Reading this Guardian article while understanding both sides of this story leads us to one conclusion: We must reboot our relationship with nature, both to reduce the climate risks, and to unlock climate solutions.
