Tracking greenhouse gas removals:
Baseline and monitoring methodologies, additionality, testing, and accounting
Authors: Matthias Poralla, Matthias Honegger, Carlos Gameros, Yuan Wang, Anne-Kathrin Sacherer, Hanna-Mari Ahonen, Lorena Morena, Axel Michaelowa
This report offers an overview of existing and planned carbon dioxide removal tracking methodologies, specific proposals for refining and revising existing ones, overcoming gaps and problems in an efficient and yet environmentally robust manner.
Limiting global warming to well below 2°C requires the full suite of mitigation activities. These efforts include drastically reducing greenhouse gas emissions as well as removing carbon dioxide already in the atmosphere. The latter is known as carbon dioxide removal (CDR). It is expected to contribute by lowering net-emissions in the near-term, achieving net-zero emissions in the medium term, and achieving overall net-negative emissions in the long term. The latest IPCC Assessment Report (AR6) highlights the need for research, development, piloting and upscaling of CDR activities through robust policy measures and markets.
Public policy instruments and private sector commitments can incentivize and support carbon removals. Alongside those efforts, we need to develop dedicated baseline as well as monitoring, reporting and verification (MRV) methodologies to track mitigation results credibly and reliably. This is true both in the context of carbon markets as well as results-based finance.
Such methodologies need to address the entire CDR ecosystem in a coherent manner. There is thus a need for a modular ensemble of methodologies for all the possible elements in and different forms of carbon capture and storage value chains (including combinations of biomass-energy with CCS, bio-waste with CCS, and Direct Air Carbon Capture and Storage) as well as various forms of carbon-use.
Furthermore, carbon-tracking methodologies are also needed for CDR methods that do not result in underground storage, but rather in the biosphere (including ecosystem preservation or restoration, soil carbon enhancement, biochar application, and forest management), in the built environment (carbon-storing cement, wood in construction), or in surface-level rock (enhanced weathering).
While there is widespread agreement on the importance of baseline- and MRV-methodologies for robust tracking of CDR results, actual methodology development has for most only started in recent years.
In this report, the authors give an overview of existing and planned CDR methodologies, offer specific proposals for refining and revising existing ones, overcoming gaps and problems in an efficient and yet environmentally robust manner.
The guiding objective of our work is to advance efforts for mitigating climate change in a consistent, transparent and environmentally sound manner. It is our belief that robust tracking is a prerequisite for the long-term credibility of carbon markets, as well as results-based financing, and policy instruments as a tool for efficient and effective climate action.