What can be done?
We should be aware that climate is changing, possibly quite independently of anything we are doing, and that these changes are, in all probability, irreversible.
Already excessive human populations make some parts of the planet highly vulnerable to such changes. Some communities already face the spectre of outrunning their available food and energy resources with every minor climate change. As population increases this will be a frightening catastrophe on two levels, the progressive destruction of land and its fertility and the inevitable death and terrible suffering of unprecedented numbers of personally innocent people.
In many areas it may already be too late to save the suffering and early death by starvation or disease of many just born or about to be born. It is desirable that the World stops and preferably reverses population growth in the areas most at risk.
Population growth is an issue of more immediate concern than climate change, which (if the greenhouse hypothesis is correct) may be but one of its symptoms. We must be careful that treating one symptom does not aggravate the disease.
The most acceptable, and so far the only successful way of controlling population growth is to provide economic and social alternatives to having many children. This requires more, not less, energy.
New extraction technologies and better energy efficiency could make existing power technology cleaner, first world economies could make greater use of nuclear power and work to make other non-polluting energy sources economical.
First world countries do need to work to reduce energy consumed per capita. Some of the options are well known, better urban planning to reduce travel, energy efficient buildings, reduced materials consumption, increased recycling, improved industrial design and so on. They can also replace part of their existing fossil energy with nuclear energy.
As technology advances so energy efficiency often improves. In the future, this may significantly impact on the energy intensity of a given standard of living. Microcomputers tele-commuting and bio-engineered materials may replace or improve the efficiency of some energy intensive technologies such as transport and materials production.
But the very commercialisation of these products and processes depends on demand for them. This increased demand may well result in more rather than less overall demand for energy. Whatever new sources of energy are chosen they will need to provide a high ratio of energy to each tonne of carbon dioxide producing materials used in energy production/collection. This may rule out wind in most locations and some types of solar power. Perhaps geothermal power or biomass offers a way forward.
Developing economies need energy at the lowest available cost. Coal and oil will remain a low cost fuels, available to meet the planet's energy needs for many decades into the future. In the absence of a cheap clean source of energy, it seems certain that burning coal and other fossil fuels will continue to supply most of the energy needs of the planet's expanding population. These fuels will remain essential for the production of food, textiles and building materials for that population and for their transport and distribution into the foreseeable future.
Thus production of greenhouse gasses will continue to rise. In the face of this reality we must develop a range of strategies to cope with the outcomes.
Large point source generators such as power stations, metallurgical and cement plants offer the potential to concentrate and dispose of carbon dioxide.
Many disposal ideas have been suggested, including pumping it into the deep oceans and into underground mineral seams. Sequestration is problematic in all but a few locations (eg over empty oil wells). It could be very costly and require significant additional energy. The environmental impact is presently unknown; for example large scale use may result in the release of already absorbed CO2 or trapped methane.
Increased biological conversion, employing sunlight to reduce the gasses back to carbon seems to be the only process that could be employed on a large enough scale to make a difference. Faster growing and harvesting of C4 plants for materials that will not be burnt (eg for paper or timber for construction) could fix more atmospheric carbon. Planting more trees has been accepted internationally as a means of earning greenhouse carbon credits but this only works if the area under forest increases and when harvested the timber is not subsequently burnt. Some food crops might be genetically modified to behave like high CO2 absorbing C4 plants. Recent work with GM rice could offer the potential of considerable gains in yield using CO2 enrichment.
Recycling can extend the useful life of plant fibres. Carbon rich materials like paper, garden waste, agricultural materials and even sewage sludge might be preferentially buried in large landfills or open cut mines (from which methane may be obtained as fuel) rather than employing incineration. This would complete the cycle back to underground carbon deposits or to create new soil for agriculture. Assisted higher absorption of carbon dioxide by crops could minimise the greenhouse effect.
But preliminary ideas on how carbon dioxide might be economically cleaned and distributed for agricultural purposes, and what crops would give the maximum economic benefit to such a project, still need to be proven.
Some of these methods may give us time, time to find better solutions to world energy needs. We need to trial a number of these ideas now.
