Climate change is being felt in all corners of the globe, and some parts of the natural world may already be undergoing irreversible changes, an assessment by the UN Intergovernmental Panel on Climate Change has found.
The report on the impact of climate change - released on Monday and the first of its kind in seven years - says the likelihood of severe and irreversible damage to the planet will grow if high greenhouse gas emissions continue and the planet warms significantly.
Amid the changes already observed in Australia are warming of surface air and ocean temperatures, and changes to precipitation. Ocean climate zones are shifting - there has been a 350-kilometre southward movement of the East Australian Current over the past 60 years.
Prime Minister Tony Abbott said the CSIRO had cautioned against attributing any particular weather event to climate change: ''Australia's is a land of droughts and flooding rains. Always has been, always will be,'' he said.
Mr Abbott said he was very happy the government had pledged to take strong climate change action heading into the election, but said the existing carbon price was a ''very dumb policy''.
Some of the future climate threats identified for Australia in the report include more coral bleaching of the Great Barrier Reef and declines in rainfall across southern NSW and Victoria.
Changes are also already being observed across the planet - the quality and quantity of water systems have been affected, wildlife are changing their range and behaviour, and the net impact on crop yields has been negative. There are early warning signs that Arctic sea ice and warm water corals are changing irreversibly. The report says some threats from climate change are considerable at just one or two degrees warming above pre-industrial levels. The average temperature across the globe has risen 0.85 degrees since 1880.
The threats become high to very high if the warming increases to four degrees.Risks under this scenario include severe and widespread damage to unique and threatened human and ecosystems, substantial species extinction and threats to global food security.
''We look around the world and see widespread impacts of the climate changes that have already occurred,'' Dr Chris Field, co-chairman of the research team behind the report, said. ''Many of these have real consequences.''
The report says the world's poor could face the most stress as climate hazards would multiply the pressures they already faced.
It said the impact of extreme weather events, such as bushfires and floods, showed a lack of preparedness in all countries, regardless of the level of development.
Labor environment spokesman Mark Butler said the points raised were ''very, very serious'' and it was a wake-up call for the government to reassess its climate position. Greens leader Christine Milne called on the government to abandon ''the foolish strategy'' of axing the carbon price.
