Addressing The Greenhouse Problem (ETI Feb 1989)
Technologies are already available which can reduce future greenhouse effect. The reasons these technologies are not being implemented, says John Coulter, are mainly institutional, not technical.
Although Arrhenius described the greenhouse phenomenon last century and occasional scientists have sounded warnings ever since, it is only in the last few years that governments and the community at large have shown any concern. Such is the nature of exponential processes that perception and response are often overtaken by events. Remember the pond with the water lily which doubles its area every minute and covers the whole pond in 60 minutes. The pond is only half covered at 59 minutes.
A number of gases blocking the long wave length radiation from the Earth are increasing in the atmosphere exponentially. This has the effect of trapping this radiation leading to an increase in surface temperature. Ice-core samples of gas obtained from Greenland and the Antarctic have revealed that the carbon dioxide concentration of the atmosphere has fluctuated between about 190 ppm and 270 ppm over the last 200,000 years, being low during periods of glaciation and high during interglacials. The level is now about 350 ppm and rising at approximately 0.5% per year.
The ice-core analysis also shows that a number of other gases are well above their pre-industrial levels and concentrations are increasing even faster than carbon dioxide. Nitrous oxide from fossil fuel burning, introgenous fertiliser use and cutting of tropical rain forest is increasing at 0.6% per annum. Methane, from natural gas, (but principally from marsh gas in rice paddies and ruminant animals) at 1.1% per annum, and chlorofluorocarbons 11 and 12 at 5 and 7% respectively. These other gases will contribute together as much greenhouse warming as CO2 over the next 40-50 years by which time the effective concentration of greenhouse gases will have doubled compared with pre-industrial times. Unless concerted action is taken before then, the rate of increase will be then much steeper and the next doubling time much shorter; such is the nature of exponential change. It has often been remarked that we are conducting a massive experiment on a global scale with no clear idea of what the result may be.
How might the problem be addressed? Two factors characterising industrial civilisation must be kept clearly in mind.
- The economic model adopted is judged by how well it can maintain exponential growth. GDP is a measure of resource flow through the economy. Pursuing economic growth means attempting to increase the dollar value (in constant dollars) of resources used up year on the year, including those resources contributing to greenhouse warming and those used in combating it. It follows that the signals indicate a growing, and by implication, a healthy economy may also be indicating further deterioration in the environment, including greenhouse warming.
- For most of this century, but particularly since the 1950s, there has been a tendency to see all problems as technical with technical solutions. Many problems are essentially social, political or institutional. Attempting to interpret these problems as technical and to find technical solutions often compounds the problem and makes its solution more intractable.
Many of the difficulties besetting an attack on greenhouse are of a complex nature requiring both institutional and technical changes. Many helpful technologies are already available; institutional barriers slow or block their adoption. In South Australia 40% of electricity is used in the home and some 40% of this is used to heat water. Solar water heaters are already well developed. The reason they are not used is that, while the capital cost of generating equipment made necessary by the purchase of an electric hot water facility is borne by the Electricity Trust (that is, other consumers), the whole capital cost is borne by the purchaser of a solar facility. This could and should be addressed by instituting a two part tariff, one part based on maximum demand (Kw) in any one rating period, the other the amount used (Kwh). Metering would involve a relatively cheap piece of electronics.
Similar efficiency gains and greenhouse emission reductions could be achieved in cooking. Over 50% of domestic stoves in South Australia are electric rather than gas. Most readers will understand the relative thermodynamic efficiency of the two ways of cooking taking into account that most electricity in South Australia is generated from gas.
Similar efficiency improvements could be made in other electricity applications and in all states in Australia. The reason the changes are not made are institutional and not technical. State Electricity authorities have an installed overcapacity; they seek to increase electricity consumption (but with no decline in end use service). Note also that increasing consumption of electricity is counted as an addition to GDP.
A wide range of energy efficiency improvments using known and established technology and equipment could be made leading to very significant reductions in most greenhouse emissions. We could probably reduce effective greenhouse emissions by 50-60% with no impairment of end use service. In all cases the reasons for non adoption are institutional, supported by easily challenged economics.
The first, technically the easiest and certainly the most cost effective, attack on greenhouse must be efficiency improvements. Beyond that a number of exciting technologies are emerging. While nuclear is slipping economically further behind (the latest USA nuclear station cost $8.6/watt to build) direct solar-electric conversion is becoming cheaper. The latest thin film solar cells developed through joint efforts of the Solar Energy Research Institute of the US Department of Energy and Arco Solar Incorporated using a copper-indium-diselenide/cadmium sulphide bilayer have achieved 11.2% efficiency at a cost of only $100 per square metre. This corresponds to approximately $3 per watt on a 24 hour basis.
The technology of transport chages beyond readily achievable efficiency improvements are more difficult to envisage. We have an enormous investment in an urban environment built around the private car. That will take some time to modify.