This document details a conceptual Framework for the Certification of Carbon Sequestration (FCCS). It is based on a system designed to support negative emissions. It provides the minimum requirements for the development of carbon sequestration standards and certificates of carbon sequestration. It allows the certification of standards so that they in turn produce certification of removed carbon that authenticates durability and verifiability. The framework (i) identifies an organizational structure for the certification system, (ii) clarifies the responsibility of participating entities, (iii) provides certificate designs and usages, (iv) details the requirements to develop measurement protocols, (v) provides mechanisms to support a long-term industry, and (vi) outlines a vision towards durable storage.

We analyze current approaches to carbon accounting for removed carbon sold on carbon markets, focusing on carbon crediting under the framing of a remaining carbon budget, the issue of durability, and approaches to accounting methodologies. We explore the topic of mixing carbon with other problems in developing carbon accounting methodologies and highlight the open policy questions. We conclude with a suggested framework for accounting for carbon removal accounting that simplifies climate action and enables a world with negative carbon emissions.

Carbon dioxide removal is necessary to mitigate climate change, but not all methods will be fit-for-purpose. Some can be unethical, unsafe, counterproductive, and ecologically damaging. But, because fitness is a value judgment, it is critical to have a clear definition of its meaning. We propose to define fit-for-purpose as an attribute of a carbon removal method that indicates that its detrimental side effects are sufficiently small to be acceptable. A method is not fit for purpose if it risks unsustainable environmental or societal damages. We then identify six criteria that can be used to judge a method’s fitness-for-purpose based on those chosen by other organizations, including carbon negativity, measurability, additionality, safety, and low environmental risks. We compare our perspectives on these criteria to those presented by six entities including Microsoft, Carbon Direct, Frontier, California’s Air Resources Board, the United Nations Development Program, and the Accountability Framework. This work reflects our thinking in 2023 with some updates in 2024 and intends to be a starting point for a more thorough development process that ought to be adopted by the international carbon removal community in an inclusive process.