Changes in global terrestrial live biomass over the 21st century

Abstract

Live woody vegetation is the largest reservoir of biomass carbon, with its restoration considered one of the most effective natural climate solutions. However, terrestrial carbon fluxes remain the largest uncertainty in the global carbon cycle. Here, we develop spatially explicit estimates of carbon stock changes of live woody biomass from 2000 to 2019 using measurements from ground, air, and space. We show that live biomass has removed 4.9 to 5.5 PgC year−1 from the atmosphere, offsetting 4.6 ± 0.1 PgC year−1 of gross emissions from disturbances and adding substantially (0.23 to 0.88 PgC year−1) to the global carbon stocks. Gross emissions and removals in the tropics were four times larger than temperate and boreal ecosystems combined. Although live biomass is responsible for more than 80% of gross terrestrial fluxes, soil, dead organic matter, and lateral transport may play important roles in terrestrial carbon sink.

Land Use Effects on Climate: Current State, Recent Progress, and Emerging Topics

“…Furthermore, the model output can be refined to provide the same type of information as the satellite-based estimates (e.g., committed emissions or aboveground biomass only), enabling comparison even of sub-component fluxes of LULCC on an apple-to-apple basis. Still, mapping of satellite-derived fluxes to model-driven estimates has to be done with care [76].…”

Detecting vulnerability of humid tropical forests to multiple stressors

“…For AGB carbon, we used the recent global live biomass carbon products available for download from (https://doi.org/10. 5281/zenodo.4161694) and described in detail in Xu et al 22 Annual AGB values at 0:1 3 0:1 grid cells from 2000 to 2018 were estimated globally using a large dataset of ground forest inventory plots of multiple censuses (>200,000 plots), systematic airborne lidar scanning data across global tropical forests (>1 Mha) and satellite lidar from Geoscience Laser Altimeter System lidar sampling measurements of vegetation height structure (>8 million samples). To map AGB, we used time series of global wall-to-wall satellite imagery from microwave and optical sensors at 0.1 spatial resolution to improve the sensitivity and uncertainty of AGB estimation globally and across tropics where cloud cover and sensitivity of satellite data at the native satellite resolution makes it difficult to estimate live biomass carbon.…”

“…For climate stress, the predictors include trends in temperature (T), vapor pressure deficit (VPD), and water balance (WB) and for human-induced stress, we used forest tree cover (TC) changes from deforestation, degradation, and fire. For ecosystem responses, we focused on the carbon cycle and included the above-ground live biomass (AGB) (2000-2018), 22 gross primary production (GPP) , ET (1982, and the vegetation skin temperature (land surface temperature [LST]) (2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015)(2016)(2017)(2018) as variables linking the water and energy balance processes with the forest carbon cycling. 23 Second, we used AR1 autoregressive models to quantify the temporal autocorrelation and the sensitivity of the ecosystem carbon cycle responses to multiple stressors.…”

The Effects of Combining the Variables in Allometric Biomass Models on Biomass Estimates over Large Forest Areas: A European Beech Case Study

“…The policies on forest-based mitigation of climate change cannot be successfully implemented without a rigorous quantification of the forest carbon stock and/or stock change [1][2][3][4][5]. Usually, forest carbon is not estimated directly; the forest biomass is first quantified and then a species-specific biomass-to-carbon ratio is used to transform biomass to carbon [3].…”