Worldwide consumption of energy has increased by nearly 70 % in the last 30 years. There are four times as many people now than there were at the beginning of the 20th century, but our energy consumption is now four times what it was then. Reserves of fossil fuels, which took millions of years to be created, will not be sufficient for much longer. For example, it is estimated that reserves of oil could be exhausted in 60 years.
Saving energy is a major problem requiring worldwide but also individual solutions.