1. Population growth
It doubled between 1950 and 1987. More people mean more mouths to feed, so we need more agriculture land. It leads to deforestation and soil erosion. Britain like other rich countries tries support developing countries, f.e. tackling basic health problems ( it organizes aid programs like family planning and others).

2. Global warming
It is caused almost by the greenhouse effect – the Earth receives energy from the sun (it’s visible light). Some of this absorbed by the Earth and some is radiated back in space. But gases in the atmosphere absorb some of this energy. Much of these gases creates heat blanket around Earth.
The likely effects: The warming 0,3 ˚C a decade. Then sea level could rise by 6 cm over next century and water could submerge some low-lying coasts (Netherlands and others). At cause of this people would migrate and that would endanger peace and international security.
The greenhouse gases: carbon dioxide, methane, nitrous oxide, chlorofluorocarbons.

3. Tropical forests
They are covering 7% land surface of the world and they are called “liver of the Earth”, because of producing oxygen, which is very important and without it we can’t live on the Earth. Amazonian forests are full of many animal and plant species that we don’t know and which can be very useful and important. Burning of forests causes emissions of carbon dioxide. Governments are supporting to encourage good forest management.

4. Biological diversity
We eliminate it by burning forests, draining forests, polluting watercourses and over fishing; so many species are driving to extinction. We are losing potentially valuable sources of food, medicine and industrial materials and depriving ourselves of future genetic resources.
The way to save the diversity on the Earth is protecting species of plants and animal life and making projects to conserve endangered species of wildlife (black rhino, African elephant).

5. Polar regions
They play a key role in setting world climate patterns and sea levels and they are homes to many unique wildlife species. Very important is funding for polar science and research.

6. The ozone layer
It protects the earth from excessive levels of UV radiation from the sun, which can cause skin cancer and eye disorders and damage crops. It’s destroyed by chlorofluorocarbons (CFCs), chemicals, used in aerosols, fridges, air conditioning, because foam and solvents are thinning the layer.
EU tries phasing out CFCs and contributes up money to help developing countries met their commitments to use alternatives to CFCs.

Maturita.cz - referát (verze pro snadný tisk)
http://www.maturita.cz/referaty/referat.asp?id=426