In his briefing to leaders of the press corps, entitled "Global Warming: Connecting the Dots from Causes to Solutions", Hansen said that evidence in the international scientific community shows global warming is occurring at a much faster pace than earlier forecasts predicted and that the burning of coal is a leading cause of elevated levels of carbon dioxide in the atmosphere, which traps heat via the so-called greenhouse effect.
"There should be a moratorium on building any more coal-fired power plants until the technology to capture and sequester the (carbon dioxide emissions) is available. [...] This is a hard proposition that no politician is willing to stand up and say it's necessary. [...] all coal-burning power plants that don't capture the CO2 will have to be bulldozed." - James Hansen, director of NASA's Goddard Institute for Space Studies.Hansen criticized climate denialists by saying that "the assumption that it takes thousands years for ice sheets to change is very wrong. [...] Because of the melting of the ice sheet, the sea level is now rising at the rate of about 35cm per century. [...] But the concern is that it is a very non-linear process that can accelerate," he said. Such a non-linear process might result in what is known as 'Abrupt Climate Change' (ACC), in which case drastic 'geo-engineering' measures on a planetary scale will have to be implemented (earlier post).
According to the U.S. Department of Energy, coal-fueled power plants produce about half of the electricity consumed in America. Plans currently call for the construction of some 160 new coal-based facilities to meet future energy needs over the next decade.
Hansen said the U.S. Congress should pass legislation to scale back the construction of these plants, but if it does not, "citizens must accomplish this." The leading scientist, who has been an outspoken critic of the Bush administration's energy policy in the past, said that the offset in electric power could be compensated by increased efforts in producing energy more efficiently.
Carbon capture and storage
Mr Hansen said the technology to capture carbon dioxide "is probably five or 10 years away":
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Carbon capture and storage (CCS) is a technique to sequester carbon emissions underground. Different options exist, such as storing the carbon in depleted natural gas and oil fields, in saline aquifers (earlier post) or in the form of a liquid (earlier post). Carbon leakage risks remain and are being studied further before the technology can be applied on a large scale (earlier post). However, several CCS pilot projects are currently already underway (earlier post).
Biomass to the rescue
CCS technologies can be applied to gas and coal power plants, but they can also be used on power plants that burn renewable and carbon-neutral biomass or biogas. Solid biofuels are currently the cheapest of all fuels (compared to coal, gas, nuclear, wind and solar) (earlier post), and they could be grown efficiently, sustainably and on a very large scale in the tropics and the sub-tropics (earlier post).
When CCS technologies are used in combination with the burning of carbon neutral biomass, this results in a system commonly known as 'Bio-Energy with Carbon Storage' (BECS). The concept is a radical carbon-negative energy system: as the biomass fuel grows in plantations, it takes CO2 out of the atmosphere and stores it in the plants; when burned as a fuel in the power plant, the released carbon is stored underground. The net effect is a reduction in atmospheric carbon. No other energy concept can achieve this (earlier post). Solar, wind, tidal, wave or nuclear power can be carbon-neutral at best.
Scientists came up with the idea of BECS in the context of 'Abrupt Climate Change', which Hansen is hinting at. They consider the concept to be the most feasible and cost-effective geo-engineering option. Other strategies, such as seeding the atmosphere with sulfur, or the oceans with fertiliser, are risky; using 'synthetic trees' or launching a gigantic mirror into space to reflect the Sun, are very costly (on these strategies, see our previous post).
In case ACC were to occur, scientists think BECS could take us back to pre-industrial CO2 levels within a matter of a few decades, and thus avert the worst catastrophes.
Coal mining sector reacts
Luke Popovich, a spokesperson for the National Mining Association, which represents the interests of U.S. coal producers, reacted to Hansen's lecture. He told the Associated Press that Hansen's comments "ought to be vetted by those who have an understanding of the energy demands placed on the U.S. economy." Popovich added that "When seen in light of those demands, then statements like that will appear unreasonable, to put it charitably."
Hansen's remarks in Washington coincide, unintentionally, with a transaction in the business world in which private financiers today announced that they will acquire one of the largest energy suppliers in the U.S. and cancel plans to develop several new coal-fueled power plants. A group led by equity specialists Kohlberg Kravis Roberts & Co. said it has offered US$32 billion to assume ownership of TXU Corp., the largest supplier of electricity in Texas, and that the board of the energy giant has accepted the offer.