Carbon farming is becoming increasingly relevant as a way to remove carbon dioxide from the atmosphere through its sequestration in agricultural ecosystems, aiming to significantly contribute to climate mitigation and adaptation. However, carbon farming schemes often focus on their biogeochemical effects, such as greenhouse gas (GHG) emission reductions, neglecting the importance of the biogeophysical aspects.
The albedo, defined as the fraction of incident solar radiation that is reflected by a surface, is arguably the most important biogeophysical parameter related to climate impact. Surface albedo is greatly affected by changes in land management or use, such as those associated with the application of carbon farming practices, and in turn generates a climate impact that can either support the climate mitigation action or partly counteract it. This issue is thoroughly addressed within the MARVIC project and has led to a discussion paper authored by Flora Desmet, Petra Sieber, Eric Ceschia, and Jens Leifeld, recently published in the journal Science of the Total Environment.
In this article, the authors explore whether the albedo effect tends to act as aco-benefit or a trade-off to the positive climate impact of different carbon farming practices, including cover crops, zero tillage, crop residue management, conversion of land from arable to grassland, or peatland rewetting, among others. Moreover, the current barriers that prevent the assessment of this effect are analysed, as well as the next steps that could lead to both qualitative and quantitative albedo accounting in the short and medium term.
In addition to this discussion paper, which can be accessed here and freely downloaded until November 18th, Desmet and Leifeld are working on the estimation of the climate impact of carbon farming practices using radiative forcing. This method considers the mitigation effect over time, accounting for trade-offs between several GHG emissions and the non-permanence of soil carbon sequestration, thus complementing the widely used CO2-equivalent metric. Currently under embargo, this report will be made public next year.
