Global warming is often thought of as a slow, gradual process that plays out over decades, but a new study by climate scientists at the Carnegie Institution for Science says the impact from burning fossil fuels can be felt in a matter of months. Carnegie's Xiaochun Zhang and Ken Caldeira compared the heat generated by burning coal, oil and natural gas with the warming caused by the resulting release of carbon dioxide into the atmosphere. It took just 34 days for the CO2-caused warming to exceed the amount of heat released by the combustion of a lump of coal. The same threshold was reached in 45 days for a single incident of oil combustion, and in 59 days for a single instance of burning natural gas. "Ultimately, the warming induced by carbon dioxide over the many thousands of years it remains in the atmosphere would exceed the warming from combustion by a factor of 100,000 or more," Caldeira said in a Carnegie news release.
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The researchers also extrapolated heat measurements for continuously burning power plants. In the case of a coal plant, models showed that it took just three months for warming caused by atmospheric carbon dioxide to surpass the heat released into the atmosphere by combustion. "If a power plant is burning continuously, within three to five months, depending on the type of power plant, the CO2 from the power plant is doing more to heat the Earth than the fires in its boiler," Caldeira said.
The research, "Time scales and ratios of climate forcing due to thermal versus carbon dioxide emissions from fossil fuels," is published in Geophysical Research Letters, a journal of the American Geophysical Union. The work was funded by the Fund for Innovative Climate and Energy Research (FICER) and the Carnegie Institution for Science.