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Why nuclear fusion research is necessary

Evolution of the carbon dioxide concentration in the air expressed in ppm (parts per million). Click on the image to enlarge.

Recent studies show that we only have fossil fuel reserves to cover the continually growing energy needs of our society for a few hundred years at the very best. This most optimistic estimate is relevant for coal. The situation for the other fossil fuels is actually less bright: a major fraction of the reserves of oil and gas have already been depleted (e.g. the USA having consumed as much as 3/4 of its petrol) and leaves only a few tens of years of reserves at the present consumption rate. During these few remaining decades a technology has to be identified that is capable of taking over the present energy production role of fossil fuels.

Long before these reserves will be depleted, we will however have to face the consequences of the fact that burning these fuels sets free large amounts of harmful gases in the atmosphere. These gases change the characteristics of the thin protective layer of air that allows life the way we know it. Oxides of sulfur and nitrogen are at the basis of acid rain. Even in the best case (burning anthracite i.e. pure carbon), the chemical reaction underlying the production of heat gives rise to the formation of a so-called "greenhouse" gas, carbon dioxide or CO2. This molecule absorbs a fraction of the infrared radiation emitted by the earth (the latter being heated itself mainly by solar energy) and thus partly blocks the efficient evacuation of excess heat. The higher the concentration of carbon dioxide in our atmosphere, the warmer the planet gets. As the atmosphere is heated up by external heating just like the air in a greenhouse, this phenomenon is known as the greenhouse effect. The physics behind it is somewhat similar to what happens when vegetables are cooked in a microwave oven, the earth playing the role of the launcher of (electromagnetic) waves, the atmosphere being the oven cavity and the water molecules (H2O) in your food being substituted for carbon dioxide molecules in the air.

Evolution of the average temperature on earth. Click on the image to enlarge.

How long can we continue injecting massive amounts of carbon dioxide in the atmosphere and what are the consequences of it on the earth's climate? Whereas some more cautious researchers claim that this greenhouse gas might - either slowly or more violently - change the climate in the future, others do not hesitate to already link the present enhanced power of the periodic "El Niño", typically accompanied by storms and floods, with the amounts of carbon dioxide man sets free in the atmosphere. Researchers may disagree on the exact magnitude of the effect, they do all share the opinion that larger amounts of greenhouse gases on average give rise to more energetic particles in the atmosphere, which unavoidably yields more violent weather (higher wind speeds, more evaporation and thus more precipitation). Whereas the precise impact on the climate may be hard to predict quantitatively (meteorologists already have a hard time making trustworthy predictions on a time scale of more than a few days; hoping to get a fully bullet-proof prediction on a time-scale of decades is akin to dreaming awake), it seems evident that we should not await the result of our global climate experiment and should explore alternative possibilities for producing energy. As carbon is "worth its weight in gold" in industrial and pharmaceutical applications, merely burning this precious and difficult to replace raw material hardly seems a worthy application in the high-tech era we live in.