The earth's climate has seen many changes in its 4.55 billion years.

The Problem: People!

people_flickr_ThisParticularGreg10,000 years ago there were no cars, planes, buses, trains or motorbikes. There was no electricity – no TVs, electric lights, fridges, microwaves, washing machines, computers, mobile phones (imagine that – no computers or mobile phones!), central heating, factories, power stations and so on. Things stayed like this for thousands of years. Humans used horses and oxen for farming and transport.

1700s: Then humans invented more complicated machines, which needed some sort of energy to power them. Coal, oil and natural gas (fossil fuels) were discovered underground.

1800s to present day: Then came electricity and the combustion engine. These both involved burning fossil fuels, which created energy for electricity and the machines, such as cars. Since their invention, industry and technology have improved rapidly, increasing the amount of power used in transport, manufacturing (making things in factories) and electricity. The population (number of people) of the world has also increased dramatically, which means even more people use transport, manufactured goods and electricity.

For more information on over-population see the factsheet Our Crowded Planet in the resources section below.

Read More: Greenhouse Gases and the Greenhouse Effect

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