BONN: Using up all known fossil fuel reserves would render Earth even more unliveable than scientists had previously projected, researchers said on Monday.
Average temperatures would climb by up to 9.5 degrees Celsius — five times the cap on global warming set at climate talks in Paris in December, they reported.
In the Arctic region -- already heating at more than double the global average -- the thermometer would rise an unimaginable 15 C to 20 C.
Burning all known reserves of oil, gas and coal would inject about five trillion tonnes of heat-trapping carbon into the atmosphere, mainly in the form of carbon dioxide, a team wrote in the journal Nature Climate Change.
This number — about ten times the 540 billion tonnes of carbon emitted since the start of industrialisation -- would be reached near the end of the 22nd century if fossil fuel trends go unchanged, it added.
Most of the UN climate science panel’s projections for greenhouse gas emissions do not forecast beyond two trillion tonnes of carbon, more than enough to unleash a crippling maelstrom of rising seas, drought, heat waves and floods.
Indeed, to have a better-than-even chance of holding global warming at 2 C, the total carbon budget, including what has already been released, is about one trillion tonnes, the UN has said.
But extreme modelling scenarios cannot and should not be ignored, said the lead author of the study.
“It is relevant to know what would happen if we do not take actions to mitigate climate change,” Kasia Tokarska, a doctoral student at the University of Victoria in British Columbia, Canada, said.