Carbon storage in the world’s forests is only at 88% of its full potential, finds a new study that aims to inform global climate strategies by pinpointing opportunities for more sequestration.
“Improved management of existing forests, such as conserving native tree species and prohibiting logging, could help realize nearly three-quarters of this unmet potential, the majority of which (71%) lies in the tropics,” writes SciDev.Net, in a summary of the study’s main conclusions.
“The size of the untapped reservoir—the space on land that is available for additional carbon storage—is considerable: about 287 petagrams (PgC) after we set aside land that is critical to food production and human habitation,” said study co-author Wayne Walker. A petagram is equivalent to one billion tonnes.
The findings can help advance the role of nature-based solutions in the international effort to hold global temperatures well below a 2.0°C increase from pre-industrial levels, which requires global emissions to stay below 250 PgC.
“We provide globally consistent maps for directing additional carbon storage under current and future climate, as well as a framework for determining how that storage could be gained through restoration, improved management, or maintenance of woody biomass and soil organic matter,” the authors write. “Our estimates provide an upper bound on how improved land stewardship can mitigate the climate crisis.”
But they stress that carbon storage cannot wholly take the place of reducing emissions.
“Any attempt to compensate an emission with an equivalent elimination will lead to an atmospheric concentration higher than if the emission had been avoided from the beginning,” the study warns.
The researchers say their approach to quantifying global carbon stocks has benefits over alternative methods because its “emphasis on continuous, spatially explicit estimates of carbon density” is more certain than relying on carbon storage calculated from tree cover or forest area. Furthermore, “the framework is intended to be flexible and non-prescriptive,” which leaves room for policies promoting terrestrial carbon storage to align with “local realities.” The data also takes into account how maximum carbon storage could shift in response to changing environmental conditions.