How much can — or should — humanity rely on nature to help solve the climate crisis?
That's the question at the center of a new study, and the study’s conclusions have some scientists scratching their heads.
As the United Nations climate talks recently concluded (with disappointing results), the study calls for a focus on "geological" climate solutions, essentially removing carbon pollution permanently by using nascent technologies — such as injecting it deep into rock formations underground. But the study dismisses the large role that forests, oceans and other natural ecosystems can play in sequestering massive amounts of climate-warming carbon.
Can nature still be part of the climate solution? And what counts as legitimate carbon removals by nature that countries can claim as climate action? Conservation News talked to Conservation International scientists Bronson Griscom and Will Turner to make sense of it all.
Question: The British newspaper The Guardian reported on this new study. Can you walk us through it?
Bronson Griscom: The paper discusses issues related to carbon accounting — specifically what governments should count toward their emissions targets. The argument is that countries are incorrectly claiming climate benefits that nature delivers whether we humans intervene or not.
An example of that is the increases in carbon removal that nature is doing because atmospheric carbon concentrations are higher. We agree with this concern, and there's every reason to think carefully about what is counted, and how. But this study is throwing the baby out with the bathwater by also dismissing the massive opportunity to enhance nature's critical role in fighting the climate crisis. Yes, we need to ensure that “passive” carbon absorption is not included in countries' climate mitigation claims. But as we do this, it is critical we do not dismiss “active” carbon sequestration — such as accelerating forest restoration — as a major climate solution around the world.
Q: Tell me more about “passive” versus “active” carbon absorption; that distinction feels important.
Will Turner: It is. There’s something like 500 gigatons CO2 equivalent of greenhouse gases going into and out of oceans and land-based ecosystems each year — it’s built into global carbon cycles. This is passive; it happens without any human intervention and therefore can’t be counted as climate action. There are also increases in CO2 removals, with plants generally removing CO2 at higher rates simply because there are higher levels of CO2 in the atmosphere. Many would call that passive as well; it doesn’t change with direct human actions.
But other things we do can directly change how much ecosystems absorb (or emit) carbon dioxide and other greenhouse gases. Actively regrowing forests, restoring degraded land, ending the destruction of forests all directly enable them to absorb and sequester more carbon. These meaningful, measurable changes — which we call “natural climate solutions” — can be counted as climate action.
Q: The study also questions whether nature can permanently remove carbon. After all, trees die and fires consume vast forests, releasing carbon back into the atmosphere. It sounds like "geological" technologies, which store carbon underground, are being held up as the only permanent climate solution.
BG: One problem is that geological technologies don’t yet exist anywhere close to the scale needed. While we will need all of the credible solutions we can get and should invest in developing these technologies, right now we urgently need cost-effective solutions to pull carbon out of the atmosphere in large amounts. Geological solutions are still decades away from being affordable or scalable. At this point, focusing solely on them risks delaying action.
It’s a bit like fixating on the quality of the water buckets you’re using when your house is on fire. Moreover, it distracts investors from cost-effective and scalable opportunities to restore ecosystems, which can deliver durable climate solutions now.
WT: For thousands of years, Earth’s ecosystems have held thousands of gigatons of carbon in a quite durable way. A world without all that carbon locked up in nature is not only an unlivable hellscape, it’s a world that no amount of technological carbon dioxide removal or other climate action could ever overcome.
What we’re saying is don't characterize all of nature as being “passive” or “impermanent.” Dismissing nature’s role in the climate fight is like leaving your best players on the bench. Forests, wetlands and other ecosystems have locked away vast amounts of carbon for thousands of years. The most important task isn’t to debate how durable that is on its own — the most important task is to ensure that it remains so.
What we need is to look at the range of solutions for both reducing emissions and removing carbon from the atmosphere, to deploy the greatest amount of both in the shortest time possible, and to ensure that they last over time.
Q: So what of this debate about technological versus natural climate solutions?
BG: The debate shouldn’t pit natural solutions against technology. There is no “either-or” — it’s “both-and,” or our goose is cooked.
We must deliver rapid reductions in fossil fuel emissions and rapid reductions in deforestation emissions and rapid increases in carbon removals.
In a few decades, I’m optimistic that carbon capture technologies will be affordable at scale — and it’s good to see significant investments in that long-term goal. But right now, ecosystem restoration is our biggest opportunity for rapid carbon removals. That’s not sitting back and hoping ecosystems save the day. We must invest more in nature. We are only just beginning to see the additional protection and restoration of ecosystems at the scale needed — I’m excited about the greener, climate-stable world our great grandkids could be living in.
Vanessa Bauza contributed to this story. Bruno Vander Velde is the managing director of content at Conservation International. Want to read more stories like this? Sign up for email updates. Also, please consider supporting our critical work.