First, the bad news. Global warming is already underway, and because its effects tend to lag by decades behind the steady increase in greenhouse gases that drive the process, we are already in worse danger than most people realize. According to climate scientists, the level of greenhouse gases has already passed the danger level of 350 parts per million. Unless fossil fuel emissions are drastically reduced, humanity faces a growing risk of dangerous global warming, as human sources are amplified by natural feedback loops.
Now the good news. There is a straightforward way to address the problem: phase out coal, which contains far more global warming potential than oil and gas combined. In fact, James Hansen, director of NASA's Goddard Space Institute, has said that ending emissions from coal "is 80% of the solution to the global warming crisis."
Hansen's explanation, summarized in various communiques such as his 4/14/08 letter to Nevada Governor James Gibbons, is as follows:
1. The amount of carbon contained in coal is vastly more than in oil and gas.
The basis of Hansen's argument for the paramount importance of coal is
that the amount of remaining coal is much larger than the amount of
remaining oil and gas and is "sufficient to take global warming close to, if not into, the realm of dangerous climate effects." The figure below shows the estimated fossil fuel reserves of the International Panel on Climate Change (IPCC) and the World Energy Council (WEC).
According to Hansen, the amount of carbon in coal, especially when combined with other fossil fuels such as tar shale, is enough "to produce a vastly different planet, a more dangerous and desolate planet, from the one on which civilization developed, a planet without Arctic sea ice, with crumbling ice sheets that ensure sea level catastrophes for our children and grandchildren, with shifting climate zones that cause great hardship for the world’s poor and drive countless species to extinction, and with intensified hydrologic extremes that cause increased drought and wildfires but also stronger rain, floods, and storms."
2. Coal use is more concentrated and therefore more controllable than oil and gas
Hansen's second argument is that coal can more easily be controlled and contained than oil and gas. Coal use is concentrated in 600 existing power plants, but oil and gas use is spread out among millions of sources. Hansen writes: "Oil is burned primarily in small sources, in vehicles where it is impractical to capture the CO2 emissions. Available oil reserves will be exploited eventually, regardless of efficiency standards on vehicles, and the CO2 will be emitted to the atmosphere. The climate effect of oil is nearly independent of how fast we burn the oil, because much of the CO2 remains in the air for centuries. (It is nevertheless important to improve efficiency of oil use, because that buys us time to develop technologies and fuels for the post-oil era, and high efficiency surely will be needed in the post-oil era.) However, the point is this: oil will not determine future climate change. Coal will."
Is phasing out coal a realistic goal? Absolutely. One source alone--concentrating solar power (CSP)--is being built around the world and can be designed with on-site thermal storage to provide baseload power. A 95-mile by 95-mile area devoted to CSP plants could supply all U.S. power needs.