Much of world’s fossil fuel must remain in ground to keep global warming below 1.5°C, says study

A new study projects massive declines in fossil fuel production to limit climate change

An oil rig in the North Sea. Philippa McKinlay, Flickr
16 September 2021
16 September 2021

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To have a 50 percent chance of keeping global warming below 1.5 degrees Celsius above pre-industrial levels, almost 60 percent of the world’s oil and gas reserves and 90 percent of coal deposits must remain in the ground, according to a recent study published in Nature. To reach this goal, oil and gas production must decline by 3 percent every year until 2050. 

According to the model, some regions of the world would have to leave a larger amount of fossil fuel resources untouched than would others. For example, 60 percent of oil and gas reserves in the Middle East would have to remain unextracted, as would 80 percent of such reserves in Canada. Central and South America would also need to keep 73 percent of oil and 67 percent of gas reserves below ground. The study works on the premise of a 2018 to 2100 carbon budget of 580 gigatonnes of carbon dioxide.

Unconventional sources – such as oil from oil sands or gas from shale rock formations – would undergo even less extraction, and Arctic oil and gas resources would remain undeveloped.

This study is an extension of 2015 research that modeled the limits of fossil fuel extraction in order to limit global warming below 2 degrees Celsius and serves as a urgent warning that concrete action is needed now more than ever. In the six years since the 2015 paper, the Paris Agreement on climate change and international bodies have lowered the warming target to below 1.5 degrees.

The Sixth Assessment Report (AR6) issued by the Intergovernmental Panel on Climate Change (IPCC) last month makes clear that the 1.5-degrees threshold will likely be reached before 2040, and with it will come more extreme weather events, sea level rises, fires, heatwaves, droughts and other extreme phenomena. 

The good news is that the rate of fossil fuel extraction is beginning to plateau, such as with the decline of coal production in the U.S. and Europe over the past few years and oil production predicted to peak within the decade.

The coal mine and power station near Bełchatów, Poland. Roman Ranniew, Flickr
The coal mine and power station near Bełchatów, Poland. Roman Ranniew, Flickr

The bad news is that this is probably not enough. Even the scenario within the AR6 report that sees greenhouse gas emissions drastically curbed and net-zero carbon emissions achieved by 2050 still estimates global heating to surpass 1.5 degrees by 2040. And even with renewable energy on the rise, 81 percent of the world’s energy still derives from fossil fuels

The study makes projections how for certain countries in particular would need to sharply cut their development of fossil fuels in order for the world to meet its climate targets. The Middle East and the U.S. would need to roughly halve their oil production. The U.S. and former Soviet Union countries would also need to steeply reduce their gas production. 

Meanwhile, countries in Africa and Asia are expected to produce more gas, due to economic development and the transition from coal, before renewables become more available later on.

The authors highlight several measures that governments can take to reduce their dependence on fossil fuels and meet the 1.5-degrees goal. Aside from policies that address fossil fuel demand, such as the carbon taxing initiatives that are already taking place in a number of countries, policymakers can also target the supply side of the market. These include removing government subsidies for fossil fuel companies, taxing fossil fuel production and banning the exploration for new reserves. Action could also be taken at the global level, such as by enacting a proposed fossil fuel non-proliferation treaty.

Renewable energy capacity is growing worldwide as it becomes cheaper, and the International Energy Agency reported a 3 percent increase in renewable energy in 2020 while demand for all other fuel types declined.

However, the study stresses that its projections likely underestimate the reductions in fossil fuel production needed to limit global heating below 1.5 degrees, as this model only shows a 50 percent chance of reaching this goal, includes the use of some carbon dioxide removal and does not consider other climate uncertainties.


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