"The Overflowing Bucket..." Fossil fuel emissions and environmental impact assessment law

“The Overflowing Bucket: the significance of fossil fuel emissions under environmental impact assessment law”
Working Paper, version 1.3 as at 7 July 2025
By Fergus Green
Email: fergus.green@ucl.ac.uk

Download the working paper (pdf)

Abstract: Despite the unfolding climate crisis, fossil fuel production is increasing, and new projects continue to be approved. When fossil fuel producers seek government approval to extract fossil fuels, they are typically required to undertake an environmental impact assessment (‘EIA’) of the proposed project, to inform the public and administrative decision-makers. These assessments, and the associated administrative decisions, often minimise the climate impacts of such projects and are thus often challenged in court by environmental groups. Such litigation faces many hurdles. A key one is the argument, often made by proponents and decision-makers, that any single project’s emissions could not have a ‘significant’ climate impact; they are just a ‘drop in the bucket’ of the climate problem. This article critically scrutinises the assumptions implicit in this argument and others an original, constructive proposal for assessing the significance of fossil fuel extraction projects’ climate impacts in a legally-appropriate manner. The proposed ‘Committed Remaining Global Carbon Budget Approach’ compares: (i) the sum of a project’s scope 1, 2 and 3 emissions and other ‘committed emissions’ from fossil fuel project-based sources of carbon dioxide emissions globally with (ii) a Paris Agreement-aligned remaining global carbon budget. I argue that this is the most appropriate approach to assessing the significance of climate impacts given the nature and objectives of EIA-informed administrative decision-making. Since committed emissions from fossil fuel projects dwarf plausible estimates of Parisaligned carbon budgets, the approach yields the conclusion that all new fossil fuel extraction projects have highly significant climate impacts; new projects add water to an already overflowing bucket. I defend this implication of the approach, as it accurately and transparently conveys to the public and decision-makers the dangers posed by new fossil fuel extraction projects.