Focus on your World: Photographs from the United Nations Environment Programme

effects of global warming. This mainly occurs as the result of the build-up in the atmosphere of carbon dioxide and other "greenhouse" gases. Scientists have identified global warming as a major threat to the future of life on earth. Planting trees to compensate for the carbon dioxide we produce is directly beneficial to the environment, contributes to new forests and sends a powerful signal to individuals, industries and governments to make the concept of sustainable development central to their thinking.