Due to industrialisation, our planet's climate has changed and we now need to focus on forms of renewable energy to maintain the future of the planet. Global warming is the increase in the average temperature of the planet which has occurred since the middle of the 20th Century.
The release of greenhouse gases is the main reason that this has occurred. These allow solar energy to pass through them, but trap the energy back in after it has been used at the surface of the Earth. Without greenhouse gases, the Earth would merely be a freezing lump, but the distribution of these has increased dramatically and frighteningly in recent times. However, it is not the science behind global warming which is vitally important, it is knowing the effects of it and how to reduce it.
In increasing order of importance, the greenhouse gases are ozone, nitrous oxide, methane, carbon dioxide and water vapour. Water vapour isn't intrinsically increased by human activity, but because warm air can hold more of it, this means that with the increase in the other greenhouse gases the levels of water vapour go up.
Carbon dioxide is where the term 'carbon footprint' comes from. This is emitted through the burning of fossil fuels such as coal, natural gas and oil, and the usage of these must be decreased as quickly as possible. On a worldwide scale, the Kyoto Protocol of 1997 aimed to do something about these, although this has not worked to as good effect as possible due to conflicting interests of different countries. In the UK, the government have been slow to acknowledge the effects of CO2 emissions, but events on the world scene such as Hurricane Katrina and the work of Al Gore have made them take note.
In scientific circles, and acknowledge in the highly regarded New Scientist and Scientific America publications, there is little doubt that global warming is in effect. Now, the aim is to use more sustainable energy sources to consolidate the future of the planet and use less of the planet's quickly decreasing amount of fossil fuels.