MORE than 70 Australian marine scientists have called for immediate action to reduce greenhouse gas emissions after the release of the first report card on the impact of climate change on the marine environment.
Oceans around the continent have warmed and become more acidic and the East Australian Current has strengthened, bringing hotter, saltier water 350 kilometres further south than 60 years ago.
This has caused coral bleaching and is the likely cause of a 10 per cent reduction in growth rates of corals on the Great Barrier Reef, according to the report, Marine Climate Change in Australia, 2009 Report Card.
Other effects include a spread of destructive sea urchins in Tasmania, the death of sea turtles in Queensland and the spread of mangroves into freshwater wetlands in northern Australia.
The report, by scientists from universities, state and territory environmental agencies, the Australian Institute of Marine Science, the Bureau of Meteorology and CSIRO, warns that two degrees of further warming is already unavoidable. ''A delay in reducing human-related emissions will result in even greater levels of climate change and subsequent impacts on marine species and habitats,'' it concludes.
Elvira Poloczanska, of the CSIRO Climate Change Adaptation Flagship, said ocean warming also meant some subtropical plants and animals were moving south into temperate waters. This had already severely affected giant kelp forests in Tasmania.
The report card, which is to be updated every two years, identifies where impacts have occurred, the predicted effects of climate change by 2030 and 2100, and scientific confidence levels in those predictions. It also outlines strategies for adapting to climate change, such as removing sea walls, increased surveillance for harmful algal blooms and managing the breeding habitats for sea birds better. A University of Wollongong researcher, Helen McGregor, said it was a ''call to arms'' for scientists, policymakers and the public to do everything possible to reduce greenhouse gas emissions.