• It was probably the constant decrease in carbon dioxide in the atmosphere - due to the development of life - that by stocking large quantities of organic matter in the form of limestone, coal or petroleum, regulated the climate (the 'Gala hypothesis' from the English ecologist, James Lovelock).

• Most of this energy comes from the burning of fossil fuels, such as oil, coal and gas, which release carbon dioxide, the main greenhouse gas, into the atmosphere.

• The remaining 80 % have been eliminated through controlling emissions, specific use reductions, or alternative technologies and fluids including ammonia, hydrocarbons, carbon dioxide and water, and not-in-kind technologies.