Table of contents
Introduction………………………………………………………………………………………………………………………….2
Observed
Changes in Australia……………………………………………………………………………………………..2
Global
warming causes…………………………………………………………………………………………………………2
Global
warming effects…………………………………………………………………………………………………………3
Global warming
Introduction:
An increase in the average temperature of the earth's
atmosphere, especially a sustained increase sufficient to cause climatic
change.( the free dictionary)
Climate change is considerate as one of the worst problems
facing the world in general and Australia in specific because it is causing a several
negative effects on the environment, human society, and nature. The increase of
carbon dioxide, methane, and other greenhouse gases has many causes such as deforestation,
pollution, and burning fossil fuels contributing to a risky effects like Widespread
extinction of species, rise in sea levels worldwide and bushfires and many
other impacts .
Observed Changes in Australia
The Bureau of Meteorology has been observing and reporting on weather in
Australia for over 100 years and presents this current pictures of Australia’s
climate changes.
Air Temperature
figure 1. Average trend in annual mean
temperature in Australia (ºc/10yrs - 1950-2001) From The Bureau of Meteorology(Australian
Online Coastal Information)
Air temperature is regularly measured across Australia. The map in figure
7 shows the average trend in annual mean temperature for areas in Australia for
the period 1950-2008 as degrees Celsius per decade, eg. 0.2 oC/10yrs for 50
years equals a 1 oC increase in mean annual temperature since 1950.
Rainfall
Rainfall is regularly measured across Australia. The map in figure 2shows
the average trend in total rainfall for Australia for the period 1950-2008 as
millimetres per decade, eg. +20mm/10yrs for 50 years equals a 100 millimetre
increase in average rainfall since 1950.
Figure 2. Average trend in total rainfall in Australia (mm/10yrs)
1950-2008. From The Bureau of Meteorology (Australian Online Coastal
Information)
Global warming causes:
The causes of climate change is a complicated topic and it is believed
that the activities and lifestyles of the earth's human population are causing
the changes.
Deforestation:
Photosynthesis is the phenomena when plants take in carbon dioxide from
the air and release oxygen, it is noteworthy that the plants are the air’s
filter .When land is cleared and trees or vegetation removed or burnt, the stored
carbon is converted back into carbon dioxide. Before European settlement in 1788,
forest and woodlands covered 54% of Australia. This has now been reduced to
42%, mainly through landclearing (World Wildlife Fund).
Increase in usage of chemical
fertilizers on croplands:
In the last half of the 20th century, the use of chemical fertilizers (as
opposed to the historical use of animal manure) has risen dramatically. The
high rate of application of nitrogen-rich fertilizers has effects on the heat
storage of cropland (nitrogen oxides have 300 times more heat-trapping capacity
per unit of volume than carbon dioxide) and the run-off of excess fertilizers
creates ‘dead-zones’ in our oceans. In addition to these effects, high nitrate
levels in groundwater due to over-fertilization are cause for concern for human
health.
Burning fossil fuels:
Most of Australia’s greenhouse gas emissions come from the burning of
fossil fuels for energy (e.g. for electricity and transport). When oil, gas or
coal burns, carbon contained within it combines with oxygen in the air to
create carbon dioxide. Australia’s electricity-related emissions are high
because we rely primarily (77%) on coal for electricity generation and coal is
the most greenhouse-intensive fuel.
Global warming effects:
The effects of rising temperatures; signs are appearing all over, and some
of them are surprising such as:
Widespread extinction of species:
Some researches show that rising temperatures could lead to the extinction
of more than a million species.
‘Climate change
now represents at least as great a threat to the number of species surviving on
Earth as habitat-destruction and modification.’Chris Thomas,
conservation biologist at the University of Leeds(Planet save)
Global warming has emerged as the single greatest threat to Australia’s
biodiversity.Scientists predict that a 1.5°C global temperature rise may see
25% of the Earth’s animals and plants disappear; a 3°C rise may see 30%
disappear.(world Wildlife Fund)
Rise in sea levels worldwide:
Scientists predict an increase in sea levels worldwide due to the melting
of ice sheets; this includes mountain glaciers, ice sheets covering West
Antarctica and Greenland, and Arctic sea ice .However, many nations around the
world will experience the effects of rising sea levels, which could displace
millions of people.
Bushfires:
Director Prof Andy Pitman(Climate System Science)predicts ‘A great deal
has been said about the recent New South Wales bush fires and whether there is
a link between these bush fires and global warming’
Most fires occur during summer, weather conditions are a critical
determinant of the fire risk. For example, high temperatures, low precipitations or,worse
still,prolonged drought, can dry out timber, grass and leaves increasing the
risk of a fire starting .
Conclusion:
In order to effectively address global warming, we must
significantly reduce the amount of heat-trapping emissions we are putting into
the atmosphere.
As individuals, we can help by taking action to reduce our
personal carbon emissions. But to fully address the threat of global warming,
we must demand action from our elected leaders to support and implement a
comprehensive set of climate solutions.
References:
