The seventh version of the European Space Agency’s global Above-Ground Biomass (AGB) dataset is now available, providing a more consistent and reliable record of the amount of carbon stored in the worlds forests over two decades. Developed by ESA’s Climate Change Initiative (CCI) Biomass project team, this latest iteration release reduces uncertainties, tto benefit the growing needs climate science and policy.
Primarily developed to benchmark and assess climate and carbon cycle model performance, which are key to improving predictions of future environmental change, the dataset increases support to national and international climate policies, namely the United Nations REDD+ framework and the Paris Agreement.
The 18 annual maps of woody AGB (tonne per hectare) cover two epochs, 2005-2012 and 2015-2024, and are available at 100 m to 1 km, 10 km, 25 km and 50 km spatial resolution.
The new version has a greater temporal coverage, provides more up-to-date observations and is of higher accuracy compared to previous version. This is a result of the research team combining the most extensive record of C-band Synthetic Aperture Radar (SAR) data from the Envisat and the Copernicus Sentinel-1 mission with longer-wavelength L-band SAR observations from the Japan Aerospace Exploration Agency's (JAXA) ALOS-1 and ALOS-2 satellite. The ability of the longer wavelength L-band to penetrate forest canopies provides more woody biomass information and facilitated more robust retrievals.
“The release provides the first near-seamless record, that consistently quantifies forest carbon covering two decades,” explains Maurizio Santoro of Gamma Remote Sensing. “The combination of temporally consistent observations by ESA and JAXA satellite radar missions has been essential to construct this time series. Trends of carbon stored by terrestrial vegetation can now be associated to environmental factors or land-use changes”.
Dr. Takeo Tadono, the Earth Observation Research Centre of JAXA, adds “we are very pleased that the CCI Biomass Product Version 7 has been developed, making use of continuous L-band SAR observation from JAXA's ALOS PALSAR and ALOS-2 PALSAR-2, provided through the partnership between JAXA and ESA and covering a period of approximately 20 years. We hope that this dataset will contribute to the scientific understanding climate change.”
Forests are constantly exchanging carbon between land and atmosphere, making them an important component, and regulator, of the climate system. Satellites provide a unique approach to quantifying and tracking changes in national to global carbon stocks over time - demonstrated in this latest dataset.
The CCI's biomass team's dataset is increasingly important in a policy context, supporting national greenhouse gas reporting, by countries seeking to demonstrate climate mitigation progress under the Paris Agreement.
“Countries are increasingly looking to consistent datasets such as ESA CCI Biomass data when estimating the carbon balance of their forests,” explains Professor Martin Herold of the German Georesearch center (GFZ) in Potsdam. “Using satellite observations provides national agencies with an important data record, helping to meet ‘transparency, accuracy, completeness, consistency and comparability’ requirements.”
The project team is advancing case studies in tropical to temperate regions through country level engagement to demonstrate utility of the data. ESA is working with several country agencies in the adoption of the CCI Biomass data for national estimation and reporting. In Brazil, work is underway to assess carbon emissions and removals by secondary forests, while the biomass maps are being integrated with National Forest Inventories to enhance estimations for Peru and Mozambique. The Global Forest Observation Initiative (GFOI) has also recently published arelated methodological guidance module for countries.
To quantify biomass change between years or at a decadal (2010-2020) timescale, a free python based tool is made available to help researchers or national agencies compute and assess AGB change.
ESA scientist, Clement Albergel adds that, “this new dataset adds to the evidence base to help deliver on the recommendations and priority action of the CEOS AFOLU roadmap as well as support national and international obligations under the UNFCCC Paris Agreement.”
Next steps will focus on extending the dataset further to improve its research value. Dr Albergel adds that, ‘the team is already investigating how to exploit JERS-1 SAR mission data from the 1990s and consider how to utilise new and continuity sensors, including the ESA BIOMASS mission and the NASA / ISRO NISAR time-series.”