Australia’s top scientists have released a “State of the Climate” report at a time of growing skepticism over climate change as a result of revelations of errors in some global scientific reports.
The scientists said their monitoring and research of the world’s driest inhabited continent for 100 years “clearly demonstrate that climate change is real.”
“We are seeing significant evidence of a changing climate. We are warming in every part of the country during every season and as each decade goes by, the records are being broken,” said Megan Clark, head of Australia’s state-backed Commonwealth Scientific & Industrial Research Organization (CSIRO).
The UN’s Intergovernmental Panel on Climate Change acknowledged in January its 2007 report had exaggerated the pace of Himalayan glaciers melting, and last month said the report also had overstated how much of the Netherlands is below sea level.
The 2007 report is based on the work of thousands of scientists and is the main policy guide for governments looking to act on climate change. Skeptics have leapt on the errors, saying they undermine the science of climate change but the IPCC, which has announced a review, has defended its work.
The CSIRO and the Bureau of Meteorology report said international research showed it is extremely unlikely that global warming could be explained by natural causes alone.
“There is greater than 90 per cent certainty that increases in greenhouse gas emissions have caused most of the global warming since the mid-20th century,” said the report.
“Evidence of human influence has been detected in ocean warming, sea-level rise, continental-average temperatures, temperature extremes and wind patterns,” said the report.
Australia, a major grains and meat producer, battled the worst drought in 100 years for most of the past decade, damaging its farm output, but in recent years the commodities sector has been recovering due to good rainfall.
The government estimated farm output for 2008-09 at A$42 billion (US$38.4 billion) out of total Australian gross domestic product of A$1.2 trillion.
Studies show that rising seas, shifting rainfall patterns and greater extremes of droughts and floods could cost Australia’s economy dearly. A government report last November said residential buildings worth up to A$63 billion could be inundated if seas rise by 1.1 metres (3.5 feet) this century.
Since 1960, the mean temperature in Australia has increased by about 0.7Cs, but some areas of the country had warmed by 1.5 to 2C in the past 50 years, the report said.
Australia’s warmest decade on record is 2000 to 2009. While total rainfall in Australia had been relatively stable, the
geographic distribution changed significantly over the past 50 years, with rainfall decreasing in southwest and southeast Australia, the major population areas.
Sea levels around the island continent since 1993 have risen seven to 10 mm per year in the north and west and 1.5 to three mm in the south and east, said the report.
From 1870 to 2007, the global average sea level rose by close to 200 mm (eight inches), sea levels rose at an average of 1.7 mm a year in the 20th century and about three mm per year from 1993-2009, it said.
Sea surface temperatures around Australia have increased by about 0.4C in the past 50 years.
The scientists said global carbon dioxide concentration in 2009 of 386 parts per million (ppm) was much higher than the natural range of 170 to 300 ppm that existed in the atmosphere for the past 800,000 years and possibly 20 million years.
The scientists said that based on their monitoring of the nation’s climate for 100 years, Australian average temperatures are projected to rise by 0.6 to 1.5C by 2030.