Imagine a world where average temperatures are almost 10 degrees Celsius higher than today, an Arctic with temperatures almost 20 degrees warmer and some regions deluged with four times more rain.
That is the dramatic scenario predicted by a team of climate scientists led by the University of Victoria’s Katarzyna Tokarska, who looked at what would happen if the Earth’s remaining untapped fossil fuel reserves are burned.
Tokarska, a PhD student at UVic’s School of Earth and Ocean Sciences, used simulations from climate models looking at the relationship between carbon emissions and warming — including the Intergovernmental Panel on Climate Change report — and concluded that known fossil fuel reserves would emit the equivalent of five trillion tonnes of carbon emissions if burned.
That would result in average global temperature increases between 6.4 degrees and 9.5 degrees Celsius, with Arctic temperatures warming between 14.7 degrees and 19.5 degrees, says the paper published Monday in the scientific journal Nature Climate Change.
“These results indicate that the unregulated exploitation of the fossil fuel resource could ultimately result in considerably more profound climate changes than previously suggested,” says the study.
“Such climate changes, if realized, would have extremely profound impacts on ecosystems, human health, agriculture, economies and other sectors.”
Simulated changes in precipitation are “extremely large,” according to the paper.
It predicts increases of more than a factor of four in areas such as the tropical Pacific and hefty decreases in precipitation over areas such as parts of Australia, the Mediterranean, southern Africa, the Amazon, Central America and North Africa.
Researchers used the lower boundary of estimates of known fossil fuels, Tokarska said in an interview with DeSmog Canada.
“The (amount of untapped fossil fuels) could be much higher as we didn’t consider unconventional sources, and then the warming would be much higher,” Tokarska said.
The highest temperatures would be reached by the year 2200, but, in the meantime, temperatures will steadily increase unless mitigation measures are taken, the study finds.
“Some people say that that’s so far off, but this is profound climate change if we follow the usual scenario,” Tokarska said.
“What we are doing is showing it’s relevant to know what will happen if we don’t take any action to mitigate climate change — if we don’t ever implement the Paris agreement or other such agreements. It’s a worst-case scenario if we don’t do anything now,” she said.
The Paris agreement, adopted in December last year, sets a target of limiting global warming to below two degrees Celsius above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5 degrees — a goal supported by Canada.
Based on previous research, the Earth is already halfway towards the two -degree increase in temperature and researchers are now looking at whether it is possible to reach that tougher 1.5 degree target, but Tokarska said they do not yet have those answers.
Worldwide there are growing calls for governments to enforce regulations to keep remaining fossil fuels in the ground and to speed up a move to green economies.
“On a personal level I can say this is kind of a warning message of the likely outcome so we can hopefully do some changes now,” Tokarska said.
Other authors of the paper include Nathan Gillett and Vivek Arora from the Canadian Centre of Climate Modelling and Analysis and Michael Eby and Andrew Weaver from UVic’s School of Earth and Ocean Sciences.
Weaver is also leader of the B.C. Green Party.
Photo: Wendy North via Flickr.