Climate change in Australia
 
Past climate change > Recent changes
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Temperature
  • Average temperatures have increased by 1-2 degrees C across Australia since 1910
  • Warming has been greatest at night and at more inland locations.
  • The frequency of hot nights has increased and the frequency of cold nights has declined.
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Rainfall
  • There were no clear annual rainfall trends from 1900 to 1949.
  • North-west Australia has seen a very large increase in annual rainfall since 1950.
  • The east coast, Victoria, and south-west Australia have all experienced substantial rainfall declines since 1950.
  • From 1910 to 1990 there has been an increase in extreme rainfall in the summer half-year, particularly in the north-east Australia.
  • There have also been increases in extreme rainfall for the winter half-year for the same period, except in far south-west Western Australia and inland Queensland.
  • In the south-west Western Australia, the winter decline in rainfall is accompanied by a sharp decrease in the totals of the extreme rainfall days with a strong decrease in the intensity of rain falling on very wet days, and in the number of very wet days.
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Extreme Events
  • Trends in most extreme events are rising faster than the change in the mean.
  • There has been an apparent decrease in tropical cyclone numbers near Australia since the 1970s, in association with more frequent El Ninos.
  • The number of more intense tropical cyclones and east coast lows has increased, while the number of weak and moderate tropical cyclones has decreased.
  • There was a 30% decline in the number of hailstorms affecting Sydney in the period 1989-2002 compared with 1953-1988.
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Drought
  • Since the start of the 20th century, the driest period across Australia was from the 1930s to the early 1940s.
  • More recent droughts have had higher maximum and minimum temperatures, and higher potential evaporation, so even though the rainfall was not as low as in the 1930s and 1940s, the severity of recent droughts has been much worse.
  • The average annual inflow into Perth's dams has decreased by approximately 50% since 1975.
  • Inflow into dams in Lake Eildon in Victoria has declined by approximately 40%.
  • In New South Wales, inflows have also decreased.
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Snow
  • Maximum winter snow depth at Spencers Creek in the Snowy Mountains of south-eastern Australia has decreased slightly since 1962, and the snow depth in spring has declined by 40%.
  • In the period 1957-2002 a week decline in maximum snow depths and a moderate decline in mid-late season snow depths has been recorded.
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Sea Level
  • Global sea levels have risen by approximately 17cm during the twentieth century.
  • Globally, the average rate of sea level rise between 1950 and 2000 was 1.8 ± 0.3 mm per year, but since 1993 (when satellite data has been available) the rate was increased to 3 mm per year.
  • Sea level rise along the Australian coast varies significantly from one location to another with a minimum sea-level rise to the north-west of Australia.
  • The change of relative mean sea level around the Australian coastline for the period 1920 to 2000 is about 1.2 mm per year, but over the past 20 years the rate is far greater.
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Oceans
  • Substantial warming has occurred in the three oceans surrounding Australia.
  • Southern Ocean temperatures have risen since the 1950s to a depth of 1000m in some locations.
  • Warming has been large off the south-east coast of Australia and in the Indian Ocean with the Indian Ocean sector of the sub-Antarctic zone recording the strongest warming of the Southern Ocean.
  • The tropical Pacific Ocean (strongly linked to ENSO) has warmed over recent decades.
  • Long term observations off Maria Island near Tasmania reveal a warming trend far greater than the global average, and this may be due to changes in the East Australia Current.
  • Since the mid-1970s, the Leeuwin Current is weaker, which this may be due to an increase in the frequency of El Nino events.
  • Since the 1960s, SSTs in the Leeuwin Current have risen by about 0.6 degrees C.
  • Since the 1950s there has been a 50 km southward migration of the Antarctic Circumpolar Current.
  • Seawater near the bottom of the ocean off Antarctica has rapidly become less salty and less dense (perhaps indicating increased melt from Antarctic glaciers).
  • The surface ocean pH has decreased by 0.1 units in the last 200 years, which is a 30% increase in the concentration of acidic hydrogen ions.
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Atmospheric Systems
  • There has been an increase in the frequency of El Nino events since 1876, although this may be part of naturally occurring variability.
  • While wet season rainfall varies enormously from year-to-year and decade-to-decade, there has been an overall increase in rainfall intensity associated with the monsoon over the past century.
  • There has been a 20% reduction in the strength of the subtropical jet stream over Australia since the early 1970s.
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More Information

Observing Australian climate change [external link]
www.bom.gov.au/climate/change/observe_climate_change.shtml

 
Department of Climate Change and Energy Efficiency
CSIRO
Bureau of Meteorology
Climate Change in Australia was developed by CSIRO and the Bureau of Meteorology in partnership with the
Department of Climate Change and Energy Efficiency through the Australian Climate Change Science Program
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