Atmosphere
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Climate Change
Introduction
Accelerated climate change is the projected result of the enhanced ‘greenhouse
effect’. The greenhouse effect is a phenomenon where certain gases in the
atmosphere trap and retain heat, which maintains the earth at a habitable
temperature. However, the increased use and combustion of fossil fuels
globally over the last 200 years has released significantly increasing amounts of
these gases into the atmosphere, which is ‘enhancing’ the greenhouse effect to
dangerous levels. The result is a rise in global mean temperatures and changes
in other elements of global climate systems, including changing rainfall patterns,
increased incidence of extreme weather events, warming and acidification of
the oceans, and rising sea levels
Keeping global mean temperature rise to below 2ºC is considered critical in
order to avoid rapid changes to the earth’s systems that would potentially trigger
catastrophic irreversible impacts, such as the melting of the Greenland ice cap.
To prevent this, scientists have advised that stabilisation of greenhouse gases
will require cuts in global greenhouse emissions of at least 80% by 2050, as a
target agreed to by leaders of developing countries
(G8 Summit 2009).
Meeting this
target will require significant cuts in greenhouse gas emissions at
international national, state and local levels. This is the ‘mitigation’ or emission
reduction challenge.
Adaptation
Alongside the requirement to effectively reduce greenhouse gas emissions, it is
important that regions and governments also begin to assess their ‘adaptation’
needs. It is accepted that even if action is taken to reduce the burden of
greenhouse gases in the atmosphere, there is an existing atmospheric load
which will take many decades to reverse. In this situation it is prudent for
governments and the community to assess what are the optimal actions to allow
our environment, society, and economy to cope with the climate impacts that
are likely to be experienced in the coming decades. This is referred to as the
‘adaptation’ challenge, and is being tackled by governments around the world.
1
1.
International examples of regional adaptation planning include the California Adaptation Plan
–
) and the City of London Adaptation Plan.
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