molecule of methane is converted to one molecule of CO2, thus reducing the global warming effect by 96%. An example of a project using an anaerobic digester can be found in Chile where, in December 2000, the largest pork production company in Chile initiated a voluntary process to implement advanced waste management systems (anaerobic and aerobic digestion of hog manure), in order to reduce greenhouse gas (GHG) emissions. Energy efficiency While carbon offsets that fund renewable energy projects help lower the carbon intensity of energy supply, energy conservation projects seek to reduce the overall demand for energy. Carbon offsets in this category fund projects of several types: Cogeneration plants generate both electricity and heat from the same power source, thus improving upon the energy efficiency of most power plants, which waste the energy generated as heat. Fuel efficiency projects replace a combustion device with one using less fuel per unit of energy provided. Assuming energy demand does not change, this reduces the carbon dioxide emitted. This can take the form of both optimized industrial processes (reducing per unit energy costs) and individual action (bicycling to work as opposed to driving). Energy-efficient buildings reduce the amount of energy wasted in buildings through efficient heating, cooling or lighting systems. In particular, the replacement of incandescent light bulbs with LED lamps can have a drastic effect on energy consumption. New buildings can also be constructed using less carbon-intensive input materials. Destruction of industrial pollutants Industrial pollutants such as hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs) have a GWP many thousands of times greater than carbon dioxide by volume. Because these pollutants are easily captured and destroyed at their source, they present a large and low-cost source of carbon offsets. As a category, HFCs, PFCs, and N2O reductions represent 71 per cent of offsets issued under the CDM. Agriculture Soil is one of the important aspects of agriculture and can affect the amount of yield in the crops. During the years of agriculture, there has been a decrease in the amount of carbon that the soil is able to hold. The soil in agriculture is now holding 50% to 66% less carbon and this is due to the many practices that farmers or scientists use. Agriculture affects the environmental quality with the losses of nitrogen and phosphorus to the fields. Soil is a key component to Green Infrastructure (GI), but most urban soils are physically, chemically,