Water and energy 50 years from now.
D000388:Air; D003031:Coal; D004560:Electricity; D005579:Fossil Fuels; D005740:Gases; D006112:Gravitation; D006358:Hot Temperature; D006801:Humans; D006838:Hydrocarbons; D009678:Nuclear Energy; D010578:Petroleum; D012623:Seawater; D012939:Social Planning; D013472:Sunlight; D014881:Water Supply; D014887:Weather
D003031:Coal; D005579:Fossil Fuels; D005740:Gases; D006838:Hydrocarbons; D010578:Petroleum