Heat is on right across the continent

Australian
Tuesday 16/3/2010 Page: 4

EVERY state and territory in Australia has warmed over the past 50 years, according to a new assessment of the state of the nation's temperature, rainfall, oceans and atmosphere. Based on observational data obtained by the Bureau of Meteorology and the CSIRO, the State of The Climate report, released yesterday, is a snapshot of current conditions and projections. "We're putting it all together changes of temperature, rainfall, atmosphere and the oceans to give a complete picture for Australia." said CSIRO chief executive Megan Clark. She noted the report was the first to reveal that observed continent-wide warming was strongest in spring and weakest in summer.

"That's something not expected by the general public," she said, noting many people assumed global warming would affect summers more than winters. Not only has the continent warmed, on average, by about 0.7C since 1960, some areas have experienced warming of up to 0.4C per decade, resulting in total warming of 1.5C-2.OC.

Rainfall has also shown variability, decreasing across southern and eastern Australia and increasing in parts of northern and central Australia. Australia's seas have also been affected by global trends. Measurements around the Southern Ocean indicate that the waters have become more acidic, as they absorb higher levels of CO2 from the atmosphere.

The ocean's acid balance affects the ability of organisms, such as corals and crustaceans, to build shells and support structures. "This is really significant here, as oceans, globally, absorb a quarter of the CO2 emitted by humans and a significant part of that, about 40%, is absorbed by the Southern Ocean," Dr Clark said. Data collected between 1870 and 2007 indicated that global sea levels had risen by nearly 200mm.

Between 1993 and 2009, sea level rose by 1.3mm to 2mm per year in the south and east of Australia and 7mm to 10 mm annually in the north and west. Based on their peer-reviewed data, BoM and CSIRO scientists project that Australia will be hotter, in coming decades, between 0.6C and 1.5C by 2030 and 2.2C to 5.0C by 2070. "The (projection) is based on the laws of physics and chemistry and observations of changes seen in the geological record and observational data, so we have confidence in the (projection)," Dr Clark said. "The information is very robust."