Keywords: energy resources, energy substitution, triangle of constraints, environmental impacts, health hazards, energy costs, sustainable development
Energy and the world: a physicist's view
The evolution of human societies depends upon the availability of energy resources. Since the word energy does not have the same meaning for physicists and the general public, this point is clarified first. Then, a selection of energy and societal problems are reviewed. Although energy per se does not drive society, it has played a major role in the successive industrial revolutions which have occurred since the end of the 18th century. Political power belongs to those who possess or control energy resources. As time elapses, a slow process of energy substitution takes place, wood being replaced by coal, then coal being replaced by oil and natural gas. Whether there will be a new shift towards nuclear energy is not yet clear. Recent concerns such as environmental impacts and health hazards are of growing importance and could influence future evolutions. Scenarios ranging from catastrophic collapse to sustainable development are elaborated; their content and implications are discussed.