Climate change: Strict fossil fuel extraction limits needed to meet 1.5°C warming limit

Nearly 60% of current oil and fossil methane gas, and 90% of coal reserves must stay in the ground by 2050 if we are to have at least a 50% chance of limiting global warming to 1.5 °C, according to a modelling study published in Nature this week. Many operational and planned fossil fuel extraction projects are not conducive to meeting internationally agreed climate targets; it is estimated that oil and gas production, for example, must decline by 3% annually until 2050 to meet these goals. Policies to restrict production and reduce demand will be needed to encourage producers to reassess production.

Fossil fuels account for 81% of the global energy consumption, but their production and use will need to decline substantially to meet internationally agreed climate goals, set out by the Paris Agreement in 2015, to limit global warming to 1.5 °C relative to pre-industrial times. In 2015, a Nature paper estimated that a third of oil reserves, half of gas reserves and over 80% of coal reserves should remain unused by 2050 to have a good chance of capping global warming at 2 °C.

Building on this previous work, Dan Welsby and colleagues assess the proportion of fossil fuels that need to be left in the ground to be in with a chance of limiting global warming to 1.5 °C. They estimate that a large increase in unextractable fossil fuel reserves is required, particularly for oil for which an additional 25% of reserves have to stay in the ground compared with the 2015 estimates. The authors also find that the decline in oil and gas production required globally by 2050 implies that many regions face peak production now or during the next decade. Moreover, the authors suggest that these results may be an underestimate as their model does not take into account future Earth system feedbacks and given uncertainties around the rate of deployment and scale of technologies needed to counteract emissions.