Threats, water quality, run-off and climate change
The Great Barrier Reef is a vast interlinking web of life. All the plants and animals on the Reef play a part in keeping this web healthy and strong, and the relationships between different organisms on the Reef have been built and maintained over many thousands of years. Humans are relative newcomers to the Reef, and we've brought some big changes. Many things that we humans do on the Reef and on land have the ability to threaten the Reef's fragile ecosystem.On the Great Barrier Reef, careful management has made sure that most of our activities do not threaten the long-term health of the Reef's ecosystem.
Ironically, the biggest threats to the Reef mainly come from human activities on land.
Sediments and nutrients, fertilisers, pesticides, toxic chemicals, sewage, rubbish, detergents, heavy metals and oil run through rivers and out to the Great Barrier Reef lagoon, where they are able to threaten plants and animals on the Reef. Land users and governments are now working together to try and improve the quality of water flowing onto the Great Barrier Reef as part of the Reef Water Quality Protection Plan.
The Earth is getting warmer, and is now higher than it has been for 2000 years. A large body of research suggests that this is due to the greenhouse gases being released into the atmosphere by activities done by humans such as burning fossil fuels and deforestation. Even small changes in temperature can have a drastic effect on the natural environment. Even the rising of the Sea's temperature by just 1 or 2 degrees centigrade can cause coral bleaching as well as death, on a worldwide scale.