Consequences of the Enhanced Greenhouse Effect for the Great Barrier Reef include rising sea surface temperatures. This increase is expected to affect natural disturbance, such as the intensity of tropical cyclones; the frequency and extent of coral bleaching; and rainfall patterns that include longer droughts and more intense rainfall events.
Increased carbon dioxide in the atmosphere also has consequences for ocean chemistry. Absorption of excess atmospheric carbon dioxide into the ocean serves to lower the pH of the seawater and inhibit the growth of calcifying organisms, including crustaceans
and corals.
Whilst the cycle of natural disturbance and subsequent recovery on the Great Barrier Reef is a normal part of life, the capacity of the ecosystem to fully recover is likely to diminish over time as the frequency and intensity of disturbance increases.
It is expected that coral species that are least resistant to disturbance, including many branching forms that create structural complexity in the coral reef habitat, may gradually tend toward recovery failure. And that ocean acidification will reduce the structural integrity of the reef matrix, making it more susceptible to erosion and the physical assault of wild weather.
The consequences of loss of structural complexity in the habitat include loss of highly specialised and endemic species, many of which carry out critical ecosystem functions. This reduction in biodiversity reduces the flow of energy through the food chain that will ultimately result in a reduction of higher trophic level predator species.
Management
On the Great Barrier Reef and in adjacent coastal catchments, climate change has prompted a strong management emphasis on making natural systems as healthy as possible to retain biodiversity and to maximise the natural capacity of ecosystems to recover after disturbance.
Following rezoning of the Great Barrier Reef Marine Park in 2004 that substantially increased the area that excludes fishing, the Great Barrier Reef Marine Park Authority emphasises stewardship by all reef users, schools, councils and agricultural industries in the Great Barrier Reef catchment. The Reef Guardians program establishes a framework for stewardship recognition based on a set of voluntary standards determined by each sector of the community engaged in the program.
On the reef, the Authority awards differential permits to Ecotourism certified tourism operators. The Authority also provides support for adaptation planning through their Climate Change Adaptation Strategy and Action Plan.
In the catchment, the Australian Government offers financial assistance to farmers to modify land management practices to reduce sediment and nutrients flowing to the sea. Regional Natural Resource Management groups focus on-ground works on ‘system repair’ and planting riparian zones of waterways. They aim to encourage terrestrial and aquatic biodiversity, and to improve the connectivity between terrestrial, riverine, estuarine and marine systems.
The scale of port developments on the Queensland coast, and the concomitant increase in shipping traffic through the Great Barrier Reef, has prompted a review of the management programs from the Queensland and Australian Governments that will guide the future management of the Queensland coastal zone, including coastal development associated with population and industrial growth.
The changes to resource management priorities, the legislative amendments, the government investment in restoration of natural systems, strategic assessment of coastal zone management, and the stewardship programs are all linked to maximising the resilience of the Great Barrier Reef in a changing climate.
Pro-vision Reef Inc. recognises the need to act to contribute to climate change mitigation on the Great Barrier Reef. The organisation has identified integration with the existing cycle of fishery assessment, management and monitoring as an appropriate mechanism. Stewardship Action Plan 2013: Mitigating Ecological Risk in a Changing Climate gives carriage to actions that assist integration and formalises critical partnership arrangements by which integration might be achieved.
