In 2030, a war was fought in Europe, using tactical nuclear weapons in a limited area. The war resulted in the destruction of dozens of cities and the spread of nuclear contamination by winds into the territories of the warring parties and neutral countries, causing a large number of civilian casualties. As the consequences became known throughout the world, calls for a total ban on nuclear weapons arose everywhere. This led to the fall of governments, especially in nuclear wars, and within a few years to the deactivation of nuclear weapons everywhere.
By 2040, nuclear power will have been harnessed for civilian use only - mainly to generate energy and heat. The focus will be on local small power plants, with patent rights freely available to all countries. The use of fossil fuels has declined significantly: even in very sparsely populated areas, they remain the overall cheapest option. Even the smog that plagued China's major cities has virtually disappeared. At the same time, green building in urban areas has taken over almost everywhere in the world. The roofs of apartment blocks are like gardens.
The use of geothermal heating has become more common, while fields and forest openings covered with solar panels have been restored to their natural state. Wind farms are being built either at sea or further away from population centres, although the higher installation and energy transmission costs are the subject of critical debate.