Existing fossil fuel extraction would warm the world beyond 1.5°C

The paper undertakes a bottom-up assessment of committed CO2 emissions from fossil-fuel producing infrastructure, specifically ‘developed reserves’(actively-producing and under-construction oil and gas fields and coal mines locked-in by past development decisions). This is therefore a subset of the total reserve estimates used in the Welsby and McGlade papers. The paper models the world’s 25,000 oil and gas fields, estimating developed reserves at the start of 2018. The oil and gas estimates reflect “the probabilistic mean (expectation) of future extraction” from projects (i.e. the amount most likely to be extracted over the life of the project, aggregated across all projects), using Rystad Energy’s UCube model. As the paper says, coal reserves are not usually considered probabilistically, so the paper estimates coal reserves under definitions of the Combined Reserves International Reporting Standards Committee definitions (2019) and uses a new dataset, drawing on different sources for information on large coal-producing countries (e.g. company financial reporting, government data, publications etc.). 

The paper finds that committed emissions from fossil fuel extraction facilities are 60% larger than the remaining 1.5°C carbon budget (580 GtCO2, from 2018, 50% probability) and exhaust 95% of the 2°C budget (980 GtCO2, from 2018, 83% probability). Of the committed emissions, 47% are from coal, 35% from oil and 18% from gas. Based on the model’s median estimate, almost 40% of developed reserves cannot be burned if we are to stay within the 1.5°C carbon budget. Without carbon dioxide removal (CDR), a significant number of existing fields and mines must be decommissioned before their reserves are extracted. The key conclusion, that developed reserves substantially exceed the 1.5°C carbon budget, is robust to uncertainties around reserves data, carbon budget and oil prices. 

The paper suggests that all undeveloped reserves should be considered unextractable. It proposes measures to keep production of coal, oil and gas reserves that are already developed within 1.5°C carbon budget. Specifically, it suggests governments should stop issuing new licenses or permits for exploration or extraction. Some existing licenses will also need to be revoked.  

The paper provides a strong technical basis to support the conclusion that no new fossil fuel exploration and extraction projects should be permitted. It can also be used to reject a proposal to further develop and invest in an existing project, or to support opposition to approved fossil fuel activities on the basis that existing activities will need to be decommissioned before the end of their expected economic operating period. Similarly, it can be used to trigger reviews of the time and extraction limits on existing licenses for approved projects on the basis that those existing fields and mines will need to be decommissioned before reserves are extracted and therefore before licenses are due to expire.