Legal guardrails on states’ dependence on carbon dioxide removal to meet climate targets

This paper explores the international legal framework within which States’ reliance on carbon dioxide removal in climate targets and emission reduction pathways is set and identifies guardrails on the extent of such reliance. While carbon dioxide removal is a vital component of the response to climate change, significant risks arise when States rely upon promises of future removals as a substitute for near-term emissions reductions. This paper focuses on the obligation of ‘due diligence’ that attaches to States in relation to their actions that cause and address climate harms. It identifies a standard against which the diligence (or lack thereof) exercised by States can be objectively measured. This standard, discussed at length in the International Court of Justice’s Advisory Opinion on Climate Change, draws on several elements relevant to the governance of climate change, including precaution, scientific and technological information, and relevant rules and international standards, especially the normative pillars of the Paris Agreement. Although this standard applies to all actions and omissions by States in relation to climate harms, it assumes particular significance in relation to carbon dioxide removal, given the distinctive risks and uncertainties associated with it. We find that an application of this stringent standard of due diligence results first, in creating a pull towards a narrower range of global emission reduction pathways which minimize overshoot of the Paris Agreement’s 1.5°C temperature goal, and second, in the emergence of indicative substantive and procedural guardrails which channel and constrain States’ reliance on carbon dioxide removal to meet their climate targets. These findings underscore the need for States to pursue deep emissions reductions alongside transparent, feasible, and coherent strategies for carbon dioxide removal.