Nature For Justice Indigenous Advisor Steve Nitah and I have been talking a lot about how to protect the Boreal forests of Canada given the enormous challenge posed by climate change.
When tackling such vast problems, knowing where to start is half the battle. Thanks to Allie Goldstein and others for their work published in the journal Nature Climate Change titled “Protecting irrecoverable carbon in Earth’s ecosystems”. It provides an extremely useful framework for thinking about how we might prioritize our efforts to combat climate change.
The authors systematically review available data and literature on land use patterns, carbon sequestration rates, current stores of carbon, ecosystem ranges, and other metrics in this detailed analysis, and ultimately offer some very sound advice about how we should approach nature-based solutions in order to have a chance of staying within IPCC recommended warming limits.
The analysis centers on three core dimensions of ecosystem carbon stocks:
Such a framing helps us focus in on areas where interventions are the most possible and have the greatest effect. Some ecosystems are unlikely to be easily managed at a local scale, for example, tundra and kelp forests. The GHGs stored in these environments are at risk of release as well, but this is more a function of globally rising temperatures (e.g. permafrost thawing) rather than direct human actions.
The quantities of vulnerable carbon also vary significantly from ecosystem to ecosystem, and are partially a function of the portion of carbon that is above / below ground biomass vs. soil organic carbon (SOC). Nearly all of the biomass carbon is lost quickly upon the most common types of land use conversion (grasslands converted for agriculture, temperate forests converted for forestry, etc.), but SOC is typically released over longer timescales. Exceptions exist; for example, when mangroves are converted to shrimp farming, around 80% of SOC is quickly lost.
Finally, the extent to which the lost carbon can be recovered is an important consideration. To analyze this, sequestration rates in biomass and soils were compared across ecosystems. The range of results is striking: tropical grasslands and young tropical forests can recover vulnerable carbon in an average of less than 30 years, whereas tropical peatlands could take millennia to do the same.
When viewed in conjunction, these three elements help us identify stores of “irrecoverable carbon,” and where interventions are most necessary / likely to have meaningful impact. This perspective leads the author to the conclusion that peatland and mangroves should be near the top of the conservation agenda. They also flag the vast expanses of temperate forests in N. America and Europe that face substantial risks from hotter droughts, insect outbreaks, forest fires, and conversion to cropland in some areas.
The authors note that very few ecosystems “can be considered truly secure without proactive planning and concerted interventions,” and that ultimately, these vast stores of carbon lie “directly within human ability to safeguard or destroy.” These statements capture the impetus for all of N4J’s efforts relating to climate change. If we want to have any chance of reigning in emissions, we would all do well to apply the framing espoused in this report, work with Steven and other First Nations in Canada and concentrate our efforts where they matter most.