Assessing the diverse environmental effects of biochar systems: An evaluation framework

Area of Science:

• Environmental Science
• Life Cycle Assessment
• Carbon Sequestration Technologies

Background:

• Biochar is recognized as a carbon dioxide removal (CDR) technology with diverse co-benefits across various sectors.
• The multifaceted effects of biochar complicate systematic environmental assessments, lacking a standardized evaluation framework.
• Existing life cycle studies often focus narrowly on carbon footprints, neglecting a comprehensive analysis of biochar's broader impacts.

Purpose of the Study:

• To bridge the methodological gap in evaluating biochar systems from a life-cycle perspective.
• To propose a general description of biochar systems and an overview of their effects.
• To develop and apply an evaluation framework for biochar's diverse environmental impacts.

Main Methods:

• Utilized life cycle theory, real-world biochar projects, and literature reviews to develop the framework.
• Classified biochar effects by life cycle stage and type, explicitly defining end-of-life and reference scenarios.
• Applied the framework to the Stockholm Biochar Project case study, modeling agroecosystem effects using empirical models.

Main Results:

• Proposed a general description of biochar systems and a comprehensive overview of their effects.
• Developed an evaluation framework classifying biochar effects into biosphere exchanges, technosphere inputs, and outputs.
• Demonstrated the framework's applicability through a case study, highlighting its potential for assessing complex agroecosystem impacts.

Conclusions:

• The developed life-cycle evaluation framework addresses the need for systematic assessment of biochar projects.
• The methodology facilitates the inclusion of diverse biochar effects, moving beyond limited carbon footprint calculations.
• This work benefits the biochar and CDR research communities and informs decision-making in biochar policy and practice.