Friday, December 19, 2008

Implications of “peak oil” for atmospheric CO2 and climate

Some people think the problems of 'peak oil' and 'climate change' are in conflict with one another. If we run out of oil then that means, whew, we'll dodge the climate change problem, right? Uh... What about the coal?

Implications of “peak oil” for atmospheric CO2 and climate: by Pushker A. Kharecha and James E. Hansen, both of NASA Goddard. Unconstrained CO2 emission from fossil fuel burning has been the dominant cause of observed anthropogenic global warming. The amounts of “proven” and potential fossil fuel reserves are uncertain and debated. Regardless of the true values, society has flexibility in the degree to which it chooses to exploit these reserves, especially unconventional fossil fuels and those located in extreme or pristine environments. If conventional oil production peaks within the next few decades, it may have a large effect on future atmospheric CO2 and climate change, depending upon subsequent energy choices. Assuming that proven oil and gas reserves do not greatly exceed estimates of the Energy Information Administration, and recent trends are toward lower estimates, we show that it is feasible to keep atmospheric CO2 from exceeding about 450 ppm by 2100, provided that emissions from coal, unconventional fossil fuels, and land use are constrained. Coal-fired power plants without sequestration must be phased out before midcentury to achieve this CO2 limit. It is also important to “stretch” conventional oil reserves via energy conservation and efficiency, thus averting strong pressures to extract liquid fuels from coal or unconventional fossil fuels while clean technologies are being developed for the era “beyond fossil fuels”. We argue that a rising price on carbon emissions is needed to discourage conversion of the vast fossil resources into usable reserves, and to keep CO2 beneath the 450 ppm ceiling.

Peak oil to worsen climate change Replacing oil with coal-derived liquid fuels is one of the scenarios for dealing with peak oil. It's a folly of a scenario because of the poor energy return-on-investment but that doesn't stop the drill-here-drill-now crowd from saying it's what we must do. The problem causing climate change is the addition of carbon and other chemicals into the atmosphere, much of which is coming from ever increasing use of fossil fuels.

While "Most future climate change will be a result of burning coal," replacing oil with other resources such as wind power or even nuclear power would push back the climate change for many more years.

Coal, the dirtiest fossil fuel, is far more plentiful than oil is or ever will be. Turning to coal as a replacement transportation fuel would lead to an even greater amount of greenhouse-gas emissions, and thus a greater threat of global climate change.

The burning of fossil fuels accounts for about 80 percent of the rise of atmospheric CO2 since the pre-industrial era, to its current level of 385 parts per million. CO2, which accounts for about half of the human-caused greenhouse gases in the atmosphere, concerns scientists because it can remain for centuries. Hansen’s previous research suggests that a dangerous level of global warming may occur if CO2 exceeds a concentration of about 450 parts per million.

In the rush to solve for peak oil we must not lose site of the other challenges facing us.

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