Greenhouse gases play a part in climate change, as they retain part of the heat radiated by the sun to the earth’s surface. Increased concentration of greenhouse gases in the atmosphere retains solar heat and the temperature of the surface of the earth is rising. This is called the (enhanced) greenhouse effect. The three greenhouse gases are carbon dioxide (CO2), methane (CH4) and laughing gas (N2O).
The contribution to the greenhouse effect is expressed in greenhouse gas equivalents (CO2 equivalents). One greenhouse gas equivalent is defined as the effect of emission of 1 kilogram of carbon dioxide (CO2). Emission of 1 kg of methane equals 21 CO2 equivalents and emission of 1 kg of laughing gas equals 310 CO2 equivalents.