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Evidence of climate change

Global changes

Evidence for global climate change is extensive and growing, and is drawn from a number of independent disciplines.

The Intergovernmental Panel on Climate Change (IPCC), formed by the World Meteorological Organisation and the United Nations Environment Programme, has conducted a comprehensive review of the scientific evidence for climate change.

The IPCC reported in 2007 that evidence from all continents and most oceans shows that many natural systems are being affected by regional climate changes, particularly temperature increases.

Warming of the climate is unequivocal, as is now evident from observations of:

• increases in global average air and ocean temperatures
• widespread melting of snow and ice
• rising global average sea level.

A host of detailed global observations provide evidence for climate changes:

• 1995 to 2006 contained eleven of the twelve warmest years on record (since 1850)
• Earth's average surface temperature has risen 0.74^oC since 1900
• heatwaves and extreme rainfall have become more common in many regions
• the sea level has risen 1.8 mm per year since 1961 and the rate is accelerating
• there have been fewer frosts and the ice sheets of Antarctica and Greenland are shrinking
• the timing of physiological processes in plants and animals is changing throughout the world, and populations are shifting their distributions.

For a climate scientist's perspective on climate change, see Real Climate.

Changes in Australia

The CSIRO and Bureau of Meteorology released the technical report Climate Change in Australia in 2007.  This report provides the most up to date assessment of climate change in Australia, and includes information from IPCC reports and other sources.  There have been a number of changes observed in Australia, including:

• average temperatures in Australia rose 0.9^oC from 1910 to 2004
• there have been more heatwaves and fewer frosts
• since 1950, annual rainfall has declined on the eastern seaboard and the south of the continent, but increased in the northwest
• since 1973, droughts have become more long-lived and intense
• since 1973 extreme rainfall events have increased in the northeast and southwest.

Observations of changes in the Australian and global climate can be viewed at the  Bureau of Meterology website.  A current picture of the Australian climate is contained in the CSIRO and Bureau of Meteorology's State of the Climate report (PDF 789kb) released in March 2010.