Gorilla graueri © Conservation International/photo by John Martin

In current conditions, the world’s total carbon budget will be spent in roughly eight years, increasing emissions-related global warming, and making it impossible to meet targets agreed under the U.N. Paris Agreement on climate change, according to scientists with the Intergovernmental Panel on Climate Change.

In order to avoid catastrophic consequences of global warming, it is not only necessary to phase out fossil fuel use, but carbon in ecosystems must be protected and their storage capacity enhanced, a new study led by Conservation International demonstrates.

The study measures the scale of the challenge and its feasibility, highlighting the potential impact of “irrecoverable” carbon stocks and recommending an assessment framework based on three criteria: manageability at the local scale; magnitude of vulnerable carbon and recoverability of ecosystem carbon if it is lost.

In this context, scientists examined ecosystems based on 15 terrestrial biomes, which included major freshwater and coastal ecosystems, to aggregate such data as carbon density and rates of carbon loss and gain after land-use conversion.

In the following interview, scientist Allie Goldstein explains some implications of the research, which found that tropical grasslands and young tropical forests have the potential to recover the full magnitude of their vulnerable carbon within 30 years, while such ecosystems as peatlands and mangroves could take centuries to recover.

Q: What’s new and exceptional about this research?

A: “We’ve always known that certain ecosystems store a lot of carbon and that ecosystems differ in terms of the amount of carbon that they store. What’s new is the use of the three criteria we applied to try to understand the recoverability aspects of carbon storage in ecosystems and that we are using it as our way of prioritizing for proactive protection.

“Irrecoverable carbon is really the carbon in ecosystems that’s still within our purview to manage—so we can still do something about it—and that if lost, couldn’t be recovered by 2050 which is basically our deadline, as a planet, for reaching net zero emissions. It’s really this aspect of carbon that helps us to identify the living carbon reserves on Earth that we can least afford to lose from a climate perspective.”

Q: In other words, there has been a general belief that all carbon can be recovered, but what you are demonstrating is that this may be a false assumption?

A: “Yes, and also that there is perhaps a difference in urgency across different ecosystems. So, for example, in tropical peatlands on average it would take over 200 years to recover that carbon if lost, whereas in tropical grasslands we found the average was 19 years. I’m not saying that the shorter timeframe means tropical grasslands are unimportant – they have a lot of other biodiversity and ecosystems services – but I think when you look at the timeframe aspect it really brings home that the carbon in certain ecosystems is more irreplaceable than others.”

Q: How do you think governments will get on board with this? Do you think that they will sit up and take notice?

A: “I hope so. This paper looks at the global scale and ecosystem-wide averages, but our next steps are further identifying exactly where these carbon-rich ecosystems are located so policymakers could identify the most important irrecoverable carbon reserves in their country or in their state or the relevant level for decision making. Part of the argument that we’re making is that prioritization based on recent loss rates is still important. That’s obviously at the frontlines of what that risk is now, but we’re hoping that irrecoverable carbon will allow governments to take a more proactive view in conservation for climate and look at risks over a five- or 10-year time horizon. As we know from history, risks can shift – sometimes unpredictably and dramatically, which means that having a framework for the areas that are most important is really helpful for how to focus attention and funding.”

Q: What do you think the likelihood is that we can actually do this in a practical sense?

A: “We excluded a few biomes where carbon can’t be managed through local decision making. The biggest example is permafrost in the far North. More carbon is locked up in the frozen soils of permafrost than in the entire atmosphere, but there’s not much we can do on a hectare-by-hectare basis to actually manage that. Some proportion of it will either be released or not based on global warming and emissions overall, which means that if you were to prioritize where to invest dollars and direct conservation, it would not be in the tundra in Siberia. However, we found that for the majority of ecosystems, the carbon is still ‘manageable,’ meaning whether it stays put or goes into the atmosphere is primarily determined by our decisions on the ground—whether we destroy ecosystems or protect them. I think it is totally possible to stop the destruction of ecosystems this generation, and we can do it without compromising food production or development. What we don’t want is for more ecosystems to reach a climate tipping point beyond which our local land-use decisions are no longer effective in safeguarding these carbon reserves.”

Q: Are the Warsaw Framework for REDD+ (Reducing Emissions caused by Deforestation and forest Degradation) and the Paris Agreement on climate change adequate for what is needed?

A: “Yes and no. I think there is a difference between the Warsaw framework itself and implementation of it. REDD+, although effective, has not reached the scale necessary to stop deforestation on a global level, but that’s more to do with financing than it is with the framework itself.  Our study points out the need to use additional tools such as the incorporation of irrecoverable carbon in protective areas designation or working with Indigenous Peoples’ and improving land tenure. REDD+ tends to focus on the flows of carbon by looking at historical loss rates to inform where it is most important to reduce emissions. We argue for a complementary approach which uses irrecoverable carbon as a prioritization for proactive protection, demonstrating where the most important areas are to focus on in the next five to 30 years, is essential. It’s really these places that we need to bring with us into the mid-century.”