VICTORIA will be a hotter and drier place by mid-century, with more desert and fewer temperate regions because of the impacts of global warming, new scientific analysis has found.
In a major report, Victoria's Commissioner for Environmental Sustainability, Kate Auty, warns the changes will put infrastructure and biodiversity at risk, and leave agriculture and endangered species exposed.
New climate modelling and analysis by the CSIRO and the Bureau of the Meteorology was carried out for the report using the UN Intergovernmental Panel on Climate Change's scenarios on future global greenhouse gas emissions.
The report says the best CSIRO estimates project a 1.37-degree rise in temperatures by 2050 for Victoria - potentially as high as 1.93 degrees - under a scenario of rapid economic growth and an energy mix of fossil fuels and renewables.
Under the same scenario, rainfall is projected to decline by 6 per cent by 2050, with the reduction potentially as high as 14 per cent. The highest 1 per cent of rainfall events will become more intense.
When natural variability is considered along with human-induced changes, the decline in rainfall is found to be as high as 17 per cent, but could also increase by 5 per cent under some scenarios.
As temperatures rise and rainfall declines, the types of local climate will begin to change across the state, with more areas of desert emerging and temperate regions disappearing as climatic conditions shift south.
In Mildura, the warm grassland climate is most likely to move to hot desert by 2050 under several of the emissions scenarios. In Avalon, the temperate climate is most likely to shift to persistently dry warm grassland.
In Melbourne, the increasing impact of the urban heat island effect - dense city infrastructure increasing temperatures - will create a climate class that is observably warmer than surrounding areas.
Under the hottest and driest outcomes modelled for a longer-term warming of four degrees by 2080, Melbourne would experience the same climate as Leeton, in central-west New South Wales, does now.
The report also said an analysis of daily and season fire danger indexes suggested ''serious'' and ''major'' fire seasons were becoming more common and non-significant seasons had become rarer, with bushfire impacts to worsen.
The changes would have major implications for the state's environment and infrastructure, Professor Auty's report said, requiring preparation for more intense bushfires and increased inundation of coastal areas.
Victoria's natural world will also be affected. As warming occurs and landscapes change, species may need to migrate to more suitable areas. But Victoria's fragmented natural habitat will limit migration for less-mobile species, such as those in high-altitude or southerly region, it says.
Professor Auty writes that to read the impacts of climate change on Victoria outlined in the analysis ''is to be deeply concerned. Calls have been made for 'aggressive' intervention. The situation we confront clearly warrants such a response across all tiers of government, industry sectors and the broader community.''
NEXT year is expected to be the hottest, or at least one of the hottest, ever recorded, the British Meteorological Office says.
The office predicts next year will be 0.43 degrees to 0.71 degrees warmer globally than the average temperature between 1961 and 1990, with a ''best fit'' of 0.57 degrees warmer. If the best fit prediction holds true, that would make next year the hottest year since instrumental records began.
So far, the warmest years on record are 2010 and 2005, both of which were 0.54 degrees above the late 20th century average of about 14 degrees.
They are followed by 1998, which was 0.51 degrees above the 1961-90 average as a result of a strong El Nino phase, which enhanced warming. This year is ranked as the ninth warmest year on record.
''Taking into account the range of uncertainty in the forecast and observations, it is very likely that 2013 will be one of the warmest 10 years in the record, which goes back to 1850, and it is likely to be warmer than 2012,'' the office said in a statement.
While local temperatures vary, on a global scale it has been 27 years since the world experienced a month that was colder than average.
THE world is on track to see "an unrecognisable planet" that is between 4 and 6 degrees hotter by the end of this century, according to new data on greenhouse gas emissions.
As United Nations climate negotiations enter their second week in Doha, Qatar, an Australian-based international research effort that tracks greenhouse gas output will release its annual findings on Monday, showing emissions climbing too quickly to stave off the effects of dangerous climate change.
The new forecast does not include recent revelations about the effects of thawing permafrost, which is starting to release large amounts of methane from the Arctic. This process makes cutting human emissions of fossil fuels even more urgent, scientists say.
The new data from the Global Carbon Project found greenhouse gas emissions are expected to have risen 2.6 per cent by the end of this year, on top of a 3 per cent rise in 2011. Since 1990, the reference year for the Kyoto Protocol, emissions have increased 54 per cent.
It means that the goal of the Doha talks – to hold global temperature rise to 2 degrees – is almost out of reach. That goal requires that emissions peak now and start falling significantly within eight years.
"Unless we change current emissions trends, this year is set to reach 36 billion tonnes of carbon dioxide from the combustion of fossil fuels, we are on the way to an unrecognisable planet of 4 to 6 degrees warmer by the end of this century," said the executive director of the Global Carbon Project, Dr Pep Canadell.
"Unless the negotiators in Doha wake up tomorrow and embrace a new green industrial revolution to rapidly change our energy systems, chances to stay below global warming of 2 degrees Celsius are vanishing very fast, if they are not already gone."
Emissions are growing in line with the most extreme climate models used by the Intergovernmental Panel on Climate Change, according to a paper in the journal Nature Climate Change that explains the Global Carbon Project's findings.
The trajectory means a temperature range of between 3.5 and 6.2 degrees by the year 2100, with a "most likely" range of between 4.2 and 5 degrees.
Although the climate has changed due to natural influences in the past, human emissions superimposed on top of natural variation is now driving change 20 times faster, according to NASA estimates. Civilisation evolved in a more moderate environment.
The new data is beginning to confirm what scientists had been warning people about for decades, said Andy Pitman, director of the Centre of Excellence for Climate System Science at the University of NSW.
"There are papers that should come with a warning: 'do not read this if you are depressed', or 'please have a stiff drink handy as you read this'. [This] paper is one such example," Professor Pitman said.
The greenhouse gas emissions path the world is taking "is not a tenable future for the planet – we cannot be that stupid as a species," he said.
Matthew England, a colleague of Professor Pitman and fellow author of Intergovernmental Panel on Climate Change reports, said: "While the science is clear that emissions reductions are required urgently, each year we are emitting more and more greenhouse gases into the atmosphere. This is like a smoker ramping up the number of cigarettes smoked each day despite grave warnings to stop smoking altogether – sooner or later this catches up with you."