Burning all known reserves of fossil fuels, from Alberta's tar sands to China's vast stores of coal, would have much graver long-term consequences than previously thought, according to climate scientists who have peered far into the future. "Not only are we going to mess up our kids' and grandkids' lives, we are going to be interfering with the way the planet works for thousands of years," says climate scientist Alvaro Montenegro, noting that much of the carbon emissions would persist in the atmosphere more than 5,000 years and drive up global temperatures for millennia.
Using sophisticated computer models, Montenegro and colleagues at the University of Victoria and the University of Chicago assessed the impact of consuming all known reserves of fossil fuels until they run out in 2300. Their simulations assume that the carbon dioxide producing by burning the fuel would waft into the atmosphere as it does today.
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The scenario developed by Montenegro's group followed the UN panel's "business as usual" emissions path. According to that projection, oil, gas and coal consumption would continue on its current trajectory until 2100, then taper off over 200 years as supplies dwindle. Some 5,134 billion tonnes of carbon, locked underground for millions of years, would wind up in the global atmosphere.
Supercomputers ran the models for almost three months to calculate how the climate would respond in the 4,500 years after the emissions finally stop. The scientists concluded that average temperatures around the globe would soar 6-8 C and would remain at least five degrees higher than pre-industrial levels for more than 5,000 years. About 75 per cent of CO2 emissions released by burning all fossil fuels would persist in the atmosphere for an average of 1,800 years before being soaked up by forests, crops or the oceans, the Victoria study reports. The rest could take much longer than 5,000 years to be absorbed.
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