Coral reefs are home to over 25 per cent of all marine life, but are threatened by many things - some natural (like storms) and some man made. Water pollution, overfishing, careless recreation (by divers for example), collection of coral and human run-off are just a few of the man made threats - and global warming is also thought to be a major concern. If the present rate of destruction continues a good proportion of the world's coral reefs could be killed within our lifetime.

Coral reefs are fragile ecosystems - they are thought to be the most sensitive ecosystem to long-term climate change as they can only tolerate a narrow temperature range. Global mean sea-surface temperatures are expected to increase by about 1-2C by the year 2100. An increase in sea temperature could lead to the death of coral by bleaching - when ocean temperatures get too high, corals turn white, or 'bleach,' and eventually die.

There are other effects which are expected to arise from global warming which could lead to the death of coral reefs:

• Global Warming is expected to cause an increase in the amount of tropical storms. These storms break up the coral due to the increased height of the waves.

• We could see an increase in the frequency of El Nino years. El Nino is characterised by changes in sea temperature - the clearest sign that an El Niño event is underway is the appearance of unusually warm water, by up to 5C, between the date line and the coasts of Ecuador and Peru.

• An increase in heavy rain events could lead to an increase in flooding events - this can have the consequence of causing more runoff from rivers - this bringing down sediment which is deposited in the seas - this sediment can damage coral.

• An increase in carbon dioxide in the atmosphere can reduce the ability of corals to form their limestone skeletons. This slows their growth and makes them fragile - it also makes it harder for them to re-grow after a tropical storm or bleaching episode.

One way or another, the future for coral reefs does not look too rosy if we carry on regardless. We can only try to reduce greenhouse gas emissions, and respect the reefs in other ways - by making sure that we collect nothing, we avoid hitting the reef with our fins when diving, we try to reduce the amount of pollution we put into our oceans etc. If we do something now, we may be able to help ensure that there are coral reefs left for our children and grandchildren to dive on.

Global Warming will have an impact on a variety of plants and species. Animals and plant species are in danger on the World's coral reefs as higher temperatures damage them.