Australia sees high chance of rising temperatures

OREANDA-NEWS. There is a high chance that average temperatures across Australia will rise for the rest of this century, according to a new government report, with average annual temperatures to be up to 1.3°C warmer by 2030 compared with the average during 1986-2005.

The Climate Change in Australia projections for Australia's natural resource management regions forecast that average temperatures could rise by between 2.8-5.1°C by 2090 based on models used in the study.

Australian average surface air temperature has increased by 0.9°C since 1910, with increasing greenhouse gases (GHGs) contributing to the rise. In recent decades inconsistent warm months have occurred more often than inconsistent cold months, said the report by scientific body CSIRO and the Bureau of Meteorology.

Australia last year experienced its third warmest year on record, which followed the warmest year on record in 2013. The latest forecast updates a previous report made in 2007 by the two government agencies.

Australian prime minister Tony Abbott has played down any scientific discussion about climate change, ignoring any economic impact from the effects of climate change because of a higher concentration of GHGs in the atmosphere.

Australian average rainfall has been increasing since the 1970s, mainly because of an increase in wet season rainfall in northern Australia. But rainfall has declined in the southeast and southwest of the continent during the cooler months. The drop in southern Australia has been linked to circulation changes in the southern hemisphere that are influenced by increasing GHGs and reductions in stratospheric ozone, the report said.

Record rainfall totals occurred in many areas during 2010 and 2011, attributable in part to the presence of strong La Nina conditions and higher than average sea surface temperatures to the north of Australia.

Throughout most of Australia, extreme rainfall events, wettest day of the year and wettest day in 20 years, are projected to increase in intensity with a high likelihood because of the understanding of physical mechanisms, the report said.

Australia, which is one of the driest continents in the world, is forecast to experience longer droughts because of the effects of climate change. The time in drought, as measured by the standardised precipitation index, is projected to increase over southern Australia, it said.

This is consistent with the projected decline in mean rainfall in the southern and eastern parts of Australia. Time in drought is projected to increase with medium or low confidence in other regions, such as northern Australia. "The nature of droughts is also projected to change, with a greater frequency of extreme droughts," it said.

Average snow depths have been lower at a number of Australian sites since the 1950s. There is a high chance that as warming progresses there will be a reduced snowfall, an increase in snowmelt and thus reduced snow cover, the report said.

There is some observational evidence for a reduced incidence of tropical cyclones, the report said. Australian iron ore exports are affected by cyclones in northwest Australia and coal exports are affected by cyclones in northern Queensland during the cyclone season, which runs between December and April.

But the short period of consistent observational records and high year-to-year variability make it difficult to detect clear trends in tropical cyclone frequency or intensity, it said. Based on global and regional studies, tropical cyclones are projected to become less frequent with a greater proportion of high intensity storms, stronger winds and greater rainfall. But the report warned that a greater proportion of storms could reach south of latitude 25 degrees south, which is just above Brisbane on the east coast and just above Geraldton on the west coast.