Our use of energy has an impact on our environment. Since a huge amount of energy is consumed in the world, the impact on environment can be large. This impact can be on a local or a global scale. Nitrogen oxide emitted by the exhaust pipe of a car pollute the environment at local scale while the CO2 emitted has an effect at the global scale.
It is estimated that the cumulative global population since the appearance of Homo sapiens has been about 80 billion people. Starting about a century ago the rate of increase of the population became very steep. Each day there is a net increase of about 3,00,000 people more on the planet (difference between babies who are born and people who die).
These new inhabitants need energy to live and this leads naturally to a continuous increase of primary energy consumption. The 1 billion wealthiest people in the world consume 66% of the food and 12 times more oil per capita than people of underdeveloped countries.
The increase in the world population and the increase of the standard of living in developing countries lead to an increase of global energy consumption which averages about 2% per year. Sustained at this level, this would lead to a multiplication of our energy consumption needs by 7 times between 2000 and 2100. This is clearly unsustainable as far as fossil resources are concerned.
Progress in the energy domain has always been necessary to meet expanding demand. The main problems associated with keeping pace with the demand are that global population increases and energy consumption per capita also increases. The load of the increasing energy demand is shifted on to the fossil fuels which have limited reserves under the earth’s crust. Also the use of these fossil fuels have polluted the environment to such a level that considerable changes in climate have been observed.
Environmental concerns are now being taken more seriously by society, and practices which were common a few decades ago are no longer as accepted today.