May 26, 2020
Holly Gibbs
Nelson Institute Center for Sustainability and the Global Environment (SAGE) associate professor of Geography, Holly Gibbs and Department of Geography graduate research fellow and ecologist, Seth Spawn have published three papers in conjunction with a set of new maps showing carbon stocks of all of the world’s living above and below ground biomass for the year 2010.
Spawn explains that plants and soils store large amounts of carbon, which help to regulate the global climate. However, some of this carbon is threatened by human activity across the globe. Therefore, knowing the behavior and location of these carbon stocks is crucial in determining how they will respond in the future as well as what can be done to mitigate climate change.
More than a decade ago, Gibbs pioneered some of the first global carbon maps that have been widely used by nations working to include land use in their climate policies.
“But until now, we’ve had a pretty coarse picture of global carbon. These maps give us a far better sense of the carbon hidden beyond just the trees – carbon stored in grasses, shrubs, crops, and even belowground in the roots of these plants. This enriched view is already improving our ability to assess the climate impacts of land use changes and scenarios,” Gibbs said.
Seth Spawn
The new maps are described in, Harmonized global maps of above and belowground biomass carbon density in the year 2010, published in Nature Scientific Data. The paper, led by Spawn, details how the maps were made. They are the first of their kind to globally combine data from biomass above and below ground, while including a comprehensive range of vegetation types.
The other two papers highlight ways these maps can contribute to biodiversity and conservation efforts globally.
Spawn was also a leading author of “Protecting irrecoverable carbon in Earth’s ecosystems” published in Nature Climate Change.
This paper explains that carbon stocks can be lost due to land use changes like deforestation and grassland conversion and that they may not recover in time to converge with current and future climate change goals. According to the paper, these carbon stocks should be considered ‘irreplaceable’ in terms of conservation and should be included in policies similar to those applied to fossil fuel reserves.
“Rates of carbon loss and recovery can help us identify ecosystems that we can’t afford to lose if we want to limit global warming. We simply can’t afford to lose large carbon stocks like peatlands, tropical forests, and even many grasslands that recover slowly,” Spawn said.
Mapping co-benefits for carbon storage and biodiversity to inform conservation policy and action published by The Royal Society further explains the importance of locating carbon stock ‘hotspots’ around the world that align with areas of high biodiversity - areas like the western Amazon Basin, Central Africa, and Southeast Asia. Gibbs and Spawn suggest that identifying these areas of overlap can help achieve climate and biodiversity goals at the same time.
“Conservation that considers carbon and biodiversity together can be a win-win,” said Spawn.
These maps are available for public use through the Oak Ridge National Laboratory's Distributed Active Archive Center for Biogeochemical Dynamics (ORNL DAAC) at: https://doi.org/10.3334/ORNLDAAC/1763