To have half a chance of meeting the Paris Agreement targets, 90% of the world’s coal and 60% of its oil and gas must remain in the ground, according to new research. The modelling also suggests that Australia (along with the rest of the Pacific) must leave at least 95% of its coal, 40% of its oil and 35% of its gas unextracted.
The researchers, who are based at University College London in the UK, used a global energy systems model to estimate the amount of currently unextracted fossil fuels that would need to remain in the ground, so that the world has a 50% chance of 1.5°C of warming.
Their results are published in Nature.
“Using a carbon budget consistent with an even chance of limiting global heating to 1.5 degrees, we found that nearly 60% of global oil and fossil methane gas reserves and 90% of coal reserves need to remain in the ground,” says Dan Welsby, lead author on the paper.
The proportion of “unextractable” fossil fuels differs from region to region, with some countries able to extract a higher percentage of their reserves and still meet carbon targets.
“The regional differences are based on the economics and the cost of production within the individual regions,” explains Welsby.
This means that Australia and other OECD Pacific countries need to leave a higher proportion of coal in the ground than the global average, but can extract slightly more gas and oil.
Oil and gas production will need to decline globally by 3% each year until 2050, and most regions must reach peak production now or within the next decade.
Dr James Price, co-author on the paper, stresses that their estimates are conservative.
“Whilst they are very strong numbers that we are reporting, they are probably a lower estimate of the unextractable amount of fossil fuels,” says Price.
Professor Frank Jotzo, director of the Centre for Climate Economics & Policy at ANU, who was not involved in the research, says that this study is a reminder of the world’s shrinking carbon budgets.
“What this study shows is the comparison between the known reserves of fossil fuels and the amounts that could still be burned,” he says.
“The picture is stark in particular for the major coal producers including Australia, where most coal deposits will need to remain untouched.”
He points out that the global economic shift towards clean energy will also make the fossil fuel industry unprofitable: “Fossil fuel-producing countries need to prepare for the inevitable decline of these industries.”
Dr Steve Pye, co-author on the paper, says that the transition away from fossil fuels needs to acknowledge places that are dependent on fossil fuel production economically.
“It’s going to be critical that support is provided to those most dependent on fossil fuel production, so that there is a buy-in to diversify economies away from oil and gas,” says Pye.
“This needs to be seen very much as a just transition that aids those most dependent and least able to shift away.”
Dr Rebecca Colvin, senior lecturer in environment, resources & development at ANU, who was not involved with the study, says this is relevant to Australian regional communities dependent on the fossil fuel sector.
“Transition planning is most successful when it is proactive rather than reactive, and led locally in line with local values and priorities rather than imposed from outside,” says Colvin.
“The new study by Welsby et al highlights the need for an open and honest discussion in Australia about equipping our regional production communities to thrive in a future that is changed as a result of global energy transition.”
Ellen Phiddian is a science journalist at Cosmos. She has a BSc (Honours) in chemistry and science communication, and an MSc in science communication, both from the Australian National University.
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