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Changes Have Already Occurred
Since 1880, the average temperature of the Earth’s surface has
increased by 0.85ºC and sea levels have risen 20cm.
Extreme weather events such as droughts, floods and
bushfires are becoming more frequent and intense.
Many major glaciers are melting, including those in
Greenland and West Antarctica.
The Arctic ice cover is shrinking, particularly in summer.
Permafrost in much of the northern hemisphere is melting.
The Oceanic Conveyor Belt
The oceans are becoming more acidic, affecting many
planktonic, shelled and reef building organisms.
Dead zones, due to lack of oxygen, are increasing in
number and expanding.
The Oceanic Conveyor Belt moves warm water
from tropical oceans to the colder oceans of the
northern hemisphere.
In recent times, much of Australia has been subjected
to extensive drought. Climate change may cause
droughts to become more frequent and severe.
Heat absorbed by the oceans is distributed by a series
of ocean currents, known as the thermohaline
circulation or the Oceanic Conveyor Belt.
It is predicted that climate change will slow or, perhaps,
even stop the Oceanic Conveyor Belt. Recent evidence
indicates that slowing has already commenced and,
should this continue, parts of the northern hemisphere
will become much colder.
How will the climate change?
Over the next 80 years it is predicted that:
• Earth’s temperature will increase by 2.6ºC to 4.8ºC.
This would be the largest temperature rise the Earth
has experienced in the last 100,000 years.
The cooling of the average temperature of
the Earth by 5ºC caused the last ice age.
• Rainfall will decrease in much of Australia,
central America and the
Mediterranean regions
and increase in tropical
Africa and the north
west region of Australia.
(Rainfall levels in
south east Asia will
remain unchanged.)
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ap
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An increase of 3ºC to 5ºC may not sound serious,
however, consider the following:
• Extreme weather events will increase in
frequency and severity.
Gr
Climate Change in Perspective
• Sea levels will rise between 26cm and 82cm.
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io
Sea level rise may cause
some Pacific island
nations to disappear
Ed
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AS/SECA04