Journal Article

Satellite passive microwaves reveal recent climate-induced carbon losses in African drylands

Kerr, Yann, Tucker, Compton, Rasmussen, Laura Vang, Brandt, Martin, Tagesson, Torbern, Rasmussen, Kjeld, Rodriguez-Fernandez, Nemesio, Fensholt, Rasmus, Mbow, Cheikh, Tian, Feng, Chave, Jerome, Verger, Aleixandre, Mialon, Arnaud, Schurgers, Guy, Wigneron, Jean-Pierre, Ciais, Philippe, Chang, Jinfeng, Fan, Lei, Al-Yaari, Amen, Zhang, Wenmin, Penuelas, Josep

2018

Overview

The African continent is facing one of the driest periods in the past three decades as well as continued deforestation. These disturbances threaten vegetation carbon (C) stocks and highlight the need for improved capabilities of monitoring large-scale aboveground carbon stock dynamics. Here we use a satellite dataset based on vegetation optical depth derived from low-frequency passive microwaves (L-VOD) to quantify annual aboveground biomass-carbon changes in sub-Saharan Africa between 2010 and 2016. L-VOD is shown not to saturate over densely vegetated areas. The overall net change in drylands (53% of the land area) was −0.05 petagrams of C per year (Pg C yr −1 ) associated with drying trends, and a net change of −0.02 Pg C yr −1 was observed in humid areas. These trends reflect a high inter-annual variability with a very dry year in 2015 (net change, −0.69 Pg C) with about half of the gross losses occurring in drylands. This study demonstrates, first, the applicability of L-VOD to monitor the dynamics of carbon loss and gain due to weather variations, and second, the importance of the highly dynamic and vulnerable carbon pool of dryland savannahs for the global carbon balance, despite the relatively low carbon stock per unit area. Low-frequency passive microwave data (L-VOD) allow quantification of biomass change in sub-Saharan Africa between 2010 and 2016, revealing climate-induced carbon losses, particularly in drylands.

• Publisher: Nature Publishing Group UK,Nature Publishing Group
• Subject: 704/106/694/2739 / 704/158/2454 / 704/172 / Annual variations / Arid zones / Biological and Physical Anthropology / Biomass / Biomedical and Life Sciences / Carbon / Deforestation / Drying / Earth and Related Environmental Sciences / Ecology / Evolutionary Biology / Geovetenskap och relaterad miljövetenskap / Humid areas / Life Sciences / Microwaves / Natural Sciences / Naturgeografi / Naturvetenskap / Optical analysis / Optical thickness / Paleontology / Physical Geography / Savannahs / Trends / Vegetation / Weather / Zoology