Oceans absorb a substantial proportion of the CO2 emitted into the atmosphere by human activities, with potentially negative effects on shell-forming organisms

In the long-term, ocean acidification is likely to be the most significant impact of a changing climate on the Great Barrier Reef ecosystem.

Concentrations of carbon dioxide (CO2) are rising rapidly in the atmosphere, due to the burning of fossil fuels and deforestation. About 25% of the extra CO2 added to the atmosphere through human activities is being absorbed by the oceans.