Climate change is the greatest ecological, economic and social challenge of our time.
Our climate is changing
In the past century, the global average surface temperature has risen by 0.74 ºC. The observed increase in average temperatures is widespread around the globe, with rising trends recorded on all continents and in the oceans.
- 7 December 2009 | Updated 14 October 2011
Introduction
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The Earth is warming
Globally, observed CO2 emissions, temperature and sea levels are rising faster than expected.
The warming has been fastest over land, and greatest in the higher latitudes of the northern hemisphere.
Global ocean temperature rose by 0.10 ºC between 1961 and 2003, to a depth of 700 metres.
In Australia, there has been a 0.9 ºC warming since 1950.
We have already observed changes to our climate that are more rapid than anything the earth has experienced for at least 1800 years.
Change is happening now
Results of this climate change include:
- retreat of glaciers and sea-ice
- a decline of 10-15 per cent of the Arctic sea ice extent and a 40 per cent decrease in its average thickness
- snow depth at the start of October has declined 40 per cent in the last 40 years in the Australian Alps
- an average sea level rise of 20 mm per decade over the last 50 years
- changes in mating and migration times of birds
- pole-ward and altitudinal shifts of plants and animals (especially in the Alpine zone)
- an increase in coral bleaching due to increased water temperature.
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Fast facts
- Global average surface temperature has risen by 0.74 ºC over the past century
- Greenhouse gas concentrations in the atmosphere have increased since 1750, and now exceed pre-industrial levels
- There is greater than 90 per cent likelihood that most of the global warming seen since the mid 20th-century is due to increases in greenhouse gas emissions
- Sea level is projected to rise further by the end of this century
