Warming threat from liquefied coal

Burning liquefied coal could play a greater role in climate change than oil and gas, reported Reuters, citing scientists at a meeting of the American Geophysical Union. Global-warming estimates are currently based on oil reserves, but scientists say the extent to which liquefied coal -- coal that has been processed into a synthetic fuel -- replaces oil and gas may be even more significant.


Coal is currently the most abundant fossil fuel, making liquefied coal an attractive alternative to oil. Industries in South Africa already use liquefaction technology, and countries such as the United States and China are looking into obtaining it. But liquefied coal produces 40 % more carbon dioxide (CO2) than oil when burned, said Ken Caldeira, a scientist at the Carnegie Institution.


"Whether there’s a little more oil or a little less oil will change the details, but if we want to change the overall shape of the warming curve, it matters what we do with coal," Caldeira said. Caldeira’s climate models show that if liquefied coal were to replace all the oil in the world, global temperatures would rise two degrees by 2042, three years sooner than if oil remained the staple fuel.


Current atmospheric CO2 levels are 385 parts per million (ppm) — and increasing at an annual rate of two ppm due to the burning of oil, coal and gas. The generally accepted atmospheric threshold is 450 ppm, but some scientists say that number should be 350 ppm.


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