The indefatigable and ever optimistic James Hansen of NASA’s Goddard Institute for Space Studies has written a letter to Japanese Prime Minister Yasuo Fukuda, who is under pressure at home to set limits on greenhouse gas emissions, stressing the urgent need to cut CO2 emissions and eventually roll them back to 350 ppm or less. The key element in Hansen’s analysis is that to do this we must phase out coal emissions.
Below are excepts from Hansen’s letter. However, I recommend that the reader read the full text (PDF), which contains many excellent charts and graphs.
Global climate is approaching critical tipping points that could lead to loss of all summer sea ice in the Arctic with detrimental effects on indigenous people and wildlife, initiation of ice sheet disintegration in West Antarctica and Greenland with progressive, unstoppable global sea level rise, shifting of climatic zones with extermination of many animal and plant species, melting of most mountain glaciers with loss of freshwater supplies for hundreds of millions of people, and a more intense hydrologic cycle with stronger droughts and forest fires, but also heavier rains and floods, and stronger storms driven by latent heat, including thunderstorms, tornados and tropical storms.
Coal is central to solution of the climate problem. Coal is not only the main cause of excess CO2 in the air today; it has the greatest potential for future emissions (Fig. 2a). Due to coal’s dominance, solution to global warming must include phase-out of coal use except where CO2 is captured and sequestered. If coal is phased out uniformly between 2010 and 2030, except where CO2 is captured, atmospheric CO2 will peak at 400-425 ppm and then begin to decline (Fig. 2b). Maximum CO2 depends upon whether EIA (Energy Information Administration) or IPCC (Intergovernmental Panel on Climate Change) oil and gas reserve estimates are more realistic.
Coal and oil differ fundamentally. Oil is used mainly in vehicles, where CO2 cannot be captured. Extractable oil is nearly half gone. Most remaining oil, much of it in the Middle East, surely will be used with the CO2 injected into the air. Limitations on drilling in the Arctic, off-shore areas, and public lands can help keep exploited reserves closer to the IPCC estimate than the larger EIA estimate, but most readily available oil will end up as CO2 in the air. In contrast, scenarios that keep coal in the ground, or used only where the CO2 is captured, are feasible.
The upshot is that large climate change, with consequences discussed above, can be avoided only if coal emissions (but not necessarily coal use) are identified for prompt phase-out. A corollary is that a strategy based on 20%, 50%, or 80% CO2 emission reduction is doomed to failure, because it would allow substantial coal emissions to continue indefinitely. Once CO2 emissions are in the air, they cannot be retrieved. The only practical solution is to avoid coal emissions.
Prime Minister Fukuda, I hope that you will look at the fossil fuel facts that I have presented above and consider the possibility for leadership in this topic, which will be so important for our children and all the inhabitants of our planet.
Finally, Prime Minister Fukuda, I would like to thank you for helping make clear to the other leaders of the eight nations the great urgency of the actions needed to address climate change. Might I make one suggestion for an approach you could use in drawing their attention? If the leaders find that the concept of phasing out all emissions from coal, and taking measures to ensure that unconventional fossil fuels are left in the ground or used only with zero-carbon emissions, is too inconvenient, then, in that case, they could instead spend a small amount of time composing a letter to be left for future generations.
This letter should explain that the leaders realized their failure to take these actions would cause our descendants to inherit a planet with a warming ocean, disintegrating ice sheets, rising sea level, increasing climate extremes, and vanishing species, but it would have been too much trouble to make changes to our energy systems and to oppose the business interests who insisted on burning every last bit of fossil fuels. By composing this letter the leaders will at least achieve an accurate view of their place in history.