By Liz Kalaugher
While you might assume that a peak and subsequent decline in oil production would be good news for the climate, there’s so much coal left that the effect is likely to be limited. “The amount of oil is not very important in determining future carbon dioxide emissions,”
said Ken Caldeira of the Carnegie Institute. “Coal is the big bear on the block.”
That said, the way that we replace oil is still significant. “Will the end of oil usher in a century of coal or a century of low carbon technologies?,” pondered Caldeira. “The need
for liquid fuels could drive coal liquefaction.”
Coal liquefaction could have a double whammy effect – coal produces more greenhouse gases per unit of energy and the liquefaction process itself also costs energy. Alternatively, if we replace oil with renewable energies such as wind, solar and nuclear, climate could benefit. And the transportation issue could be solved, at least on the automobile front,
by technologies such as plug-in hybrid electric vehicles charged by electricity from renewable sources.
“There is more than enough coal to keep emissions above 350 ppm well into the next century,” agreed Pushker Kharecha of NASA GISS and Columbia University Earth Institute. Together with NASA’s Jim Hansen, Kharecha is recommending that emissions are brought back down to 350 ppm from today’s levels of 385 ppm in order to maintain a planet similar to that on which civilization developed. “That’s still feasible but it will take Herculean efforts,” said Kharecha. The move will require a phase-out of emissions from coal by 2030, as well as reforestation, a stop to deforestation, and improved agricultural practices.
Kharecha believes that in the near-term off-the-shelf technologies such as renewable energies and energy efficiency and conservation are the answer, with nuclear power using a closed fuel cycle and carbon capture and sequestration kicking in as mid- to long-term options. “It’s do-able now, what’s missing is the will,” he said.
A small glimmer of hope came from David Rutledge of California Institute of Technology, who has been re-assessing fossil fuel supplies. Having examined historic government estimates of coal reserves in the UK and oil resources in the US, where production of each fuel has peaked, he believes that governments tend to overestimate their fossil fuel reserves. According to Rutledge, fitting curves to cumulative production can give stable estimates of world resources.
“If there’s much less coal than we thought that’s good news for climate,” said Caldeira. “But we can’t just wait for coal to diminish on its own, we must take policy measures.”