If the world wants to avoid a full-blown climate catastrophe, the overwhelming majority of the planet’s fossil fuel reserves must remain in the ground, according to a new study published in the journal Nature this week. 

Scientists at University College London used modeling to reveal that 60 percent of current oil reserves, 60 percent of fossil methane gas, and 90 percent of coal reserves must stay in the ground by 2050 if Earth is going to have at least a 50 percent chance of limiting global warming to 1.5 °C (2.7°F) above pre-industrial levels.

"The bleak picture painted by our scenarios for the global fossil fuel industry is very probably an underestimate of what is required and, as a result, production would need to be curtailed even faster," the study concludes.

An instant divorce from fossil fuels is not feasible — many parts of the world still heavily rely on them for their energy needs and financial revenue. So, the research broke down the analysis by region, identifying how much of each region’s fossil fuel reserves needs to remain unextracted to meet this 1.5 °C (2.7 °F) limit, while still meeting energy demands.

To pull off the dramatic reduction in fossil fuels, much of the world needs to start cutting down on fossil fuel production now. Some regions may have until 2025 to start reducing production, but it's clear that global production must peak soon. Moving forward, global oil and gas production must decline by 3 percent annually until 2050 if we are to stand a chance of not exceeding 1.5 °C (2.7 °F) of global warming. 

The findings show that the US must keep 31 percent of its oil reserves unextracted, as well as 52 percent of its gas and 97 percent of its coal. Europe must leave 72 percent of its oil reserves, 43 percent of gas reserves, and 90 percent of its coal reserves. As for China and India, it's 47 percent of their oil reserves, 35 percent of gas reserves, and 76 percent of coal reserves. Crucially, all undeveloped Arctic reserves need to remain in the ground.

If these reductions are not met immediately (or, for some regions, by 2025), then we are more than likely going to exceed global warming to 1.5 °C (2.7 °F). As highlighted by the latest report from the Intergovernmental Panel on Climate Change (IPCC), a world that’s 1.5 °C (2.7 °F) warmer will bring worrying changes to our planet, namely increasing heat waves, longer warm seasons, shorter cold seasons, and an uptick of extreme weather events. 

The IPCC report also suggests it’s possible we could reach this grim milestone before 2050. Nevertheless, the researchers of this study argue that we must still strive to keep the majority of fossil fuel reserves unextracted as any reduction in carbon emission will help to soften the impact of the climate crisis.

"The IPCC suggested that, by 2040 we may have already reached 1.5 °C [2.7 °F], but getting as close to 1.5 °C [2.7°F] as possible will off-set impacts of our changing climate,” Dan Welsby, study author and researchers at UCL’s Institute for Sustainable Resources, said at a press conference.

The researchers insist that the reductions are perfectly possible on a practical level, although it remains to be seen whether policy makers and industry will act promptly enough.

"Are they [the reductions] possible? Technically, yes, certainly," Welsby said cautiously. "By no means are we suggesting these are easy reductions, no matter the region in question, but certainly they are technically possible.”