Analyzing the Spatiotemporal Patterns of Forests Carbon Sink and Sources Between 2000 and 2019

Abstract

Here we present a global time‐series of global forest above ground biomass from 2000 to 2019, analyzing spatiotemporal patterns of carbon balance, accounting for losses and gains. We generated a global Above‐Ground Biomass (AGB) map for the year 2000 and assessed its correlation with different satellite products. We generated a multi‐year analysis of AGB changes at the pixel level was generated, estimating carbon (C) loss and gain. Finally, we estimated the C losses due to forest clearing and wildfires analyzing their trends across biomes and countries. Our results show that the global mean annual loss was 2.88 ± 0.33 PgC yr−1, while global mean C gain was 2.95 ± 0.43 PgC yr−1, resulting in a neutral to sink behavior of −0.06 ± 0.58 PgC yr−1. The mean annual C loss by forest clearing was 1.04 ± 0.03 PgC yr−1, with an increasing trend of +0.03 ± 0.01 PgC yr−1. Eight biomes and 54 countries showed a significant increasing trend of C loss by forest clearing. Wildfires C losses reached 0.351 ± 0.02 Pg C yr−1, representing the 33.71% of forest clearing C losses. Boreal forest presented the highest C losses from wildfires, while significant increasing trends were evidenced in five biomes. We also find increasing trends of wildfire C loss in 20 countries while decreasing trends were identified in 10 countries. Our findings highlight the importance of designing strong policies to halt deforestation as agreed in the recent COP26 and provide information to identify priority areas to start implementing these policies in the short term.

Leveraging Uncertainty in Terrestrial Ecosystem Carbon Stocks and Fluxes

“…Regions with high uncertainty in C stocks and fluxes, including many semi‐arid regions globally (Ahlström et al., 2015) (see Figure S4 of Alaniz et al. (2022)), are likely to be useful as test systems for developing new techniques for quantifying ecosystem C, both for the aboveground component of the ecosystem and the subsurface (Konings et al., 2021). Subsurface C remains a major uncertainty in terrestrial C budgets and requires increased recognition and further research (Georgiou et al., 2021; Sulman et al., 2018).…”

“…Alaniz et al. (2022) find important spatial patterns in forest permanence risks. For example, the western United States stands out as a region experiencing a strong increase in forest loss due to wildfire over recent decades.…”

“…(2022) from Table 2 of Alaniz et al. (2022). Values reported for all studies with a minimum of a nine‐year record post 2000 for cross‐comparability.…”

“…Using their synthesized biomass product of seven combined maps from the year 2000, Alaniz et al. (2022) extend the record to 2019 using MODIS vegetation continuous fields, and attribute C losses to fire and forest clearing using MODIS burned area and forest loss maps (Hansen et al., 2013), respectively. Alaniz et al.…”

“…Alaniz et al. (2022) document biomes and countries where there are accelerations in C loss due to wildfire and human harvesting, as well as regions where there are large uncertainties in estimates of forest C stocks and fluxes.…”