A method and an apparatus for reducing discharges of greenhouse gases, particularly carbon dioxide. Carbonaceous materials, wood, pieces of vegetation, products made therefrom, and especially vegetative and municipal wastes poorly suitable for energy production, are treated in such a way that the release of carbon dioxide back to the atmosphere is reduced and restrained substantially. This is accomplished such that an organic mass is carbonized by heating in a charring reactor (2) in an oxygen-free or limited-oxygen volume to charcoal (20), the amount of which is more than 50 % of the carbon content of the dry mass matter, and to a gas mixture (30), from which, after its burning and the recovery of primary energy, at least water vapour is condensed to water and the released heat is exploited on a counterflow principle in a countercurrent heater (1) in the heating and drying of materials to be fed into the process. The resulting charcoal (20) can be exploited in the purification of bodies of water and as soil conditioner.