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ForestGEO carbon data supports global-scale analyses regarding forest-based climate change mitigation

Dr. Kristina J. Anderson-Teixeira leads ForestGEO's Ecosystems and Climate Program out of her lab at the Smithsonian Conservation Biology Institute. In 2016, she published the first version of ForC, an open access database integrating published, ground-based measurements of carbon stocks and annual fluxes in forest ecosystems. The database presently holds more than 29,000 records from over 3,000 sites (visit ForC’s interactive map here). Fifty sites from the ForestGEO network, spanning temperate, tropical, subtropical, and boreal biomes, have published carbon data currently included in ForC. The repository increasingly facilitates global-scale analyses that shape forest-based climate change mitigation strategies, thereby serving as a bridge from ForestGEO’s on-the-ground data collection to informed climate action.

A map detailing the scope and depth of ForC’s data. Credit: https://forc-db.github.io/

For example, in 2018 Lutz, et al. published “Global importance of large-diameter trees,” a paper that would become a top-cited article in Global Ecology and Biogeography between 2018 and 2019. Within this study researchers used carbon data from 48 ForestGEO sites and demonstrated that, consistently across a global scale, large-diameter trees play an outsized role in storing carbon, thus meriting targeted conservation strategies. Kristina’s team later recorded the biomass estimates in ForC, making them readily available for analyses seeking to quantify the value of forest conservation for climate change mitigation.

One such effort came from the Intergovernmental Panel on Climate Change (IPCC), which is the UN’s body to aggregate and disseminate climate science to inform government climate change responses. The IPCC provides guidance on accounting for forest land in national greenhouse gas inventories, including default estimates for biomass and biomass change across the world’s forests. These values are used to estimate the degree to which tropical and subtropical forests sequester and store CO2 that would otherwise contribute to warming – a vital piece of information for climate negotiations and policies. Guidelines published in 2006, however, were based on sparse data. These values were updated last year in the 2019 Refinement to IPCC Guidelines for National Greenhouse Gas Inventories (chapter on Forest Land), to which Kristina contributed. The updates for sub(tropical) forest biomass and biomass change drew upon ForestGEO data included in ForC, as well as data from other ForestGEO publications, e.g., Chave, et al. 2008.

The updates to biomass change estimates were published in Global Change Biology by Requena Suarez, et al.: “Estimating aboveground net biomass change for tropical and subtropical forests: Refinement of IPCC default rates using forest plot data.” In their analysis the researchers were able to increase the accuracy of the default rates –for example, by distinguishing between old-growth and >20-year old secondary forests (categories that were previously lumped). Having plot-based carbon data accessible strengthened the accuracy of IPCC’s science, which is the foundation for solid climate change policy.

Most recently Goldstein, et al. authored “Protecting irrecoverable carbon in Earth’s ecosystems” in Nature Climate Change (March 31, 2020). This paper was a collaboration between 8 institutional partners, including the Smithsonian Conservation Biology Institute. To avoid reaching a climate tipping point in 2050, fossil fuel use must be sharply curtailed. Additionally, however, extant carbon sinks must stay intact. Some will not; permafrost, for example, will thaw as temperatures rise. Others, though, remain within human purview and ability to protect. Which ones, though, are the most critical, and of those, feasible? Using data from ForC (including plot data from 50 ForestGEO sites) to guide their analysis, the authors assessed conservation priorities of carbon stores in different biomes with three criteria: 1) manageability at the local scale, 2) magnitude of vulnerable carbon, and 3) recoverability of ecosystem carbon, if lost. Their analysis identified old-growth forests, mangroves, peatlands, and marshes as irrecoverable sources of carbon – that is, carbon stores that must remain as such in order to avoid surpassing a 1.5°C increase in global average temperature by 2050.

Figure 3 from “Protecting irrecoverable carbon in Earth’s ecosystems.”

Goldstein, et al. close their paper with a number of approaches to protecting these irrecoverable carbon stores, including: international trade agreements, increased rights and resources to indigenous peoples (who steward 293 Gt C in tropical forests), and new protected area designations.

Central to ForestGEO is a long-standing commitment to quality data and to collaboration. Kristina’s work on ForC is a leading example of the critical insights and analysis that can be garnered through partnerships, a model of science that provides heightened accuracy, which is all the more necessary as global change accelerates.