Your millennium issue discusses 10 of the biggest unsolved problems in physics (December 1999 pp21-24 and pp53-58). I believe that one of the most vital set of problems facing physicists and mankind itself is what to do about pollution, the dwindling reserves of fossil fuel, and a rapidly changing global climate. The environment is one issue that gives enormous scope for new ideas, for widening the physics-based energy-technology possibilities, and for influencing governments to take wise decisions in energy policy that will lead to greater climate stability. It is physicists who know about these issues and it is physicists who should be at the forefront of debate on energy use and climate change.
Continuing concern for the climate was expressed at the Kyoto summit in 1997, which led to agreements to reduce emissions of greenhouse gases, including carbon dioxide. Physicists should certainly support government initiatives to develop renewable-energy technologies such as wind power, wave power, solar energy and hydroelectricity, but it should be clearly pointed out that government targets for reducing carbon dioxide can only be met through a growing programme of nuclear power. Renewable energy on its own will not meet these targets. The environmental case for the role of nuclear plants in reducing emissions of carbon dioxide should be strongly presented, in spite of the unfavourable press for nuclear energy. France is the perfect example of a country that has invested heavily in nuclear plants and as a result has seen its pollution levels fall dramatically.
Research into nuclear fusion also needs the support of the entire physics community. The recent withdrawal of the US from the International Thermonuclear Experimental Reactor (ITER) is regrettable. Emitting little or no radioactivity and requiring no fossil fuels, this essential energy technology of the future should really be classified as a renewable-energy source, because fusion reactors will be fuelled by deuterium obtained from sea water. Physicists should lead a stronger lobbying effort for both of these nuclear technologies.
There are also many other types of renewable energy that could reduce our dependence on fossil fuels. These include photovoltaics, fuel cells, and the use of hydrogen as an energy-storage medium - whether in compressed or liquid form, or in solid carbon or metal structures. If renewable energy is to play a major role, then energy-storage technology will play a vital part in this development. Batteries, flywheels and superconducting magnets are among the other energy-storage methods that need to be supported.
Energy policy cannot be divorced from energy technology, and alternatively fuelled vehicles with consequent cleaner air for cities is one example. Others include more efficient electricity generation with embedded generation and more efficient combined-cycle gas turbines, and a climate-change levy on fuel bills replaced by a carbon levy. I believe that electricity from CO2-free nuclear plants and from renewable non-polluting sources should not have any levy.
The huge potential for physics and physicists to get more involved in energy technology and in lobbying for a sensible energy policy that can deliver results is a future opportunity that should be grasped. It is up to physicists to give the lead where others feel unsure of the way ahead.
Arnold Jackson
Bangor, Northern Ireland