That isn’t necessarily a bad thing. They represent a number of gases in the atmosphere surrounding the earth that have been protecting it for thousands of years by keeping the average temperature stable. The development of human society and the means it has used to achieve its goals have resulted in a dramatic increase in the amounts of these gases in the atmosphere, particularly carbon dioxide, methane and nitrogen oxides. These gases are emitted in the use of mineral fuels for heating, transport and energy production generally. For example, in 2010, greenhouse gas emissions are expected to be 39 percent higher than in 1990. The result is a gradual but steady rise in temperatures and a destabilized climate. Scientists believe that over the next 100 years, the average temperature on the planet will rise by 1.4 to 6 degrees Celsius, with dramatic effects on life on Earth.