The Earth absorbs radiation from the sun to provide heat and energy for life.  Some of the radiation is reflected back into space but clouds and a natural layer of atmospheric gases prevent part of the radiation from escaping.

This natural greenhouse effect warms the Earth by as much as 30 °C.  Without this effect our planet would be uninhabitable.  Greenhouse gases, both natural and manmade, include carbon dioxide, nitrous oxide, methane and water vapour.

Global warming means rising temperatures and changing environmental conditions in every country; but these temperature rises will not be spread evenly across the year or the world. We must expect uncharacteristic summer heat waves that will overwhelm old and frail people.  Although milder winters will reduce the loss of life from cold, the lack of frosts may result in more diseases for humans, animals and plants.  We will have to adjust to new illnesses from warmer climates.

Deforestation is the second biggest cause of atmospheric carbon dioxide emissions after power generation.

Forests undergo ‘slash and burn’ deforestation that releases the stored carbon in the trees back into the atmosphere.  So not only is the natural ability of forests to remove carbon dioxide from the atmosphere through photosynthesis being removed; but de-forestation is a major cause of global warming.  And the rate of destruction is increasing. 

Global warming will increase temperatures and reduce rainfall in many countries.  Increased evaporation will worsen the effects of the droughts.

Conversely, although increased water vapour will add to the greenhouse effect there will be higher rainfall in other areas.  The rainfall is likely to be more intense, eroding the land and causing flooding.

 Perhaps the most visible effects of global warming are the sights of melting ice caps and retreating glaciers.

These events contribute to global warming through the loss of the albedo effect, with land absorbing heat rather than the snow and ice reflecting the radiation.  These melts are causing sea levels to rise with loss of habitats resulting in the extinction of both plant and animal species.

Our climate system varies through natural cycles of carbon emission and absorption.  However, our excessive burning of fossil fuels has disturbed this balance.
The planet has a natural regulation system that can cope with most natural fluctuations that result in changes in temperature or changes in atmospheric gases.  Plants and the oceans, for instance, naturally absorb the carbon released from human and animal respiration and digestion, decaying vegetation, solar activity, volcanoes and fires.  However the Earth is struggling to cope with the increase in greenhouse gases in the atmosphere.