We hear about Global Warming and Climate Change in the news from
devastating hurricanes to heat events - but what is it and what can we
do to help stop Global Warming? Is it bad to do things like drive a car
or use electricity? Not if done in a responsible manner. Learn why and
how, and more about Global Warming with the information below.
What is Global Warming?
Global Warming is an increase in the near surface temperature of the
Earth. It is a term most often used to refer to the warming predicted
to occur as a result of increased emissions of greenhouse gases. It is
different from the term climate change in that climate change is more
broad and refers in the wider sense to also include natural changes in
climate. Climate change and global warming have occurred on Earth as the
result of natural influences and in cycles throughout the history of the
Earth; however, the current warming we are experiencing and that is expected
to continue is the result of human-caused increases in greenhouse gases,
specifically carbon dioxide. There is more carbon dioxide in the atmosphere
now than there has been in the past 650,000 years. The carbon dioxide
stays in the atmosphere and acts like a warm blanket that holds in the
heat. This phenomenon is called the greenhouse effect.
One thing to keep in mind is that having some greenhouse gasses in our
atmosphere is not bad. We do need some warmth on the Earth or we would
not have the proper narrow range of temperature that allows us to have
the right conditions for breathable air, clean water and mild weather.
In fact, the Earth in general would be too cold to inhabit without some
greenhouse gasses or the greenhouse effect. However, humans have begun
to tip the balance and overload the atmosphere with too many greenhouse
gases from our cars, factories and power plants gasses that trap
more heat and can lead to devastating changes in our environment. If we
dont start fixing the problem now, we are in for more extreme temperatures,
rises in sea levels and more destructive storms.
Why Should I Be Concerned About Global Warming?
Global Warming affects us all. We only have one planet, one home, that
sustains the lives of all of the living things on it. Climate change itself
is not bad and is a normal part of our Earths history. The difference
with the Global Warming we are experiencing now is that it is human-caused
and happening at a faster rate than previously predicted by scientists.
Global Warming is expected to mean the melting of ice, flooding of coastlines,
increased health risks, and more extreme weather conditions and events
in our lifetime and the future.
According to the National Academy of Sciences, the Earth's surface temperature
has risen by about 1 degree Fahrenheit in the past century, with accelerated
warming during the past two decades. Since the Industrial Revolution,
more and more greenhouse gasses have been added to our atmosphere as a
result of automobiles, factories and power plants. Because there are uncertainties
surrounding Global Warming (e.g., how much warming, how fast, how devastating),
it is a difficult topic for some to grasp. What is know with certainty
is that human activities are adding greenhouse gasses to the atmosphere,
and that these gases have been shown to warm the Earth. The risks that
Global Warming poses are real. Because the exact nature of the outcomes
is still an unknown, and may not be known for decades, we must use our
best judgment guided by what we do know from science to help with our
response. Learn more about what is being done to help stop Global Warming.
You will find more information there about the impacts of Global Warming
on the following topics:
I will only cover a few topics which I believe are some of the most critical
and most notorious that we get to see and hear so much in the news. The
other topics are for you to investigate or perhaps to discuss in your
classroom with your teacher.
Changing climate is expected to increase both evaporation and precipitation
in most areas of the world. In those areas where evaporation increases
more than precipitation, soil will become drier, lake levels will drop,
and rivers will carry less water.
Lower river flows and lower lake levels could impair navigation, hydroelectric
power generation, and water quality, and reduce the supplies of water
available for agricultural, residential, and industrial uses. Some areas
may experience both increased flooding during winter and spring, as well
as lower supplies during summer. In Californias Central Valley,
for example, melting snow provides much of the summer water supply; warmer
temperatures would cause the snow to melt earlier and thus reduce summer
supplies even if rainfall increased during the spring. More generally,
the tendency for rainfall to be more concentrated in large storms as temperatures
rise would tend to increase river flooding, without increasing the amount
of water available.
Climate change could impair navigation by changing average water levels
in rivers and lakes, increasing the frequency of both floods during which
navigation is hazardous and droughts during which passage is difficult,
and necessitating changes in navigational infrastructure. On the other
hand, warmer temperatures could extend the ice-free season.
Changes in the flows of rivers would have a direct impact on the amount
of hydropower generated, because hydropower production decreases with
lower flows. Because of the ambiguous projections of changes in future
river flow, studies of the impacts of climate change show ambiguous effects
on hydropower production
Environmental Quality and Recreation
Decreased river flows and higher temperatures could harm the water quality
of a nation's rivers, bays, and lakes. In areas where river flows decrease,
pollution concentrations will rise because there will be less water to
dilute the pollutants. Increased frequency of severe rainstorms could
increase the amount of chemicals that run off from farms, lawns, and streets
into the nations rivers, lakes, and bays.
Although the impacts of sea level rise and associated coastal flooding
have been more widely discussed, global climate change could also change
the frequency and severity of inland flooding, particularly along rivers.
Polar regions such as Alaska, the Arctic, and Antarctica
contain a wide variety of physical features and ecosystems. The alpine
and lowland glaciers, ice caps, sea ice, permafrost, boreal (see glossary)
forests, tundra, peatlands, and meadows found in high-latitude regions
are sensitive to subtle variations in air temperature, ocean temperature,
and other climatic conditions.
Climate models indicate that global warming will be felt most acutely
at high latitudes, especially in the Arctic where reductions in sea ice
and snow cover are expected to lead to the greatest relative temperature
increases. Ice and snow cool the climate by reflecting solar energy back
to space, so a reduction in their extent would lead to greater warming
in the region.
- Many changes already are apparent in high-latitude regions. For example:
* Arctic temperatures during the late 20th century appear to have been
the warmest in 400 years.
* Satellite data suggest that the extent of snow cover has declined
by 10 percent since the late 1960s.
* During the 20th century, the annual duration of lake and river ice
cover in the mid- and high latitudes of the northern hemisphere declined
by about two weeks.
* Since the 1950s, the extent of northern hemisphere spring and summer
sea-ice decreased by about 10 to 15 percent, and researchers have measured
a decline of roughly 40 percent in the thickness of Arctic sea-ice during
late summer and early autumn during the past several decades.
* Since the 1950s, Alaska has warmed by an average of 4 degrees Fahrenheit.
* Pine Island Glacier, part of the West Antarctic Ice Sheet, thinned
by up to 1.6 meters (5.2 feet) per year between 1992 and 1999.
Sea ice regulates exchanges of heat, moisture, and salinity in the polar
ocean, and provides key habitat for wildlife.
A loss of sea ice leaves coasts more vulnerable to storm surges and erosion
and alters the habitat of marine mammals such as polar bears, ring seals,
and beluga whales, possibly affecting their population numbers or distribution.
Satellite data indicate record reductions in regional sea ice cover in
recent years. Climate models project large continued losses of sea ice
in the future.
Researchers reported in 1999 that a decline in
the health of polar bears during the past two decades may be linked to
rising spring temperatures in Hudson Bay and the early breakup of sea
ice. Scientists from the Canadian Wildlife Service determined that polar
bears' health may be declining from improper nutrition. Polar bears hunt
one of their primary food sources, ringed seals, in the spring months
on the sea ice. During the past 20 years, warmer temperatures have led
the ice to break up about three weeks earlier in the season. This early
breakup leaves less time for the bears to hunt seals and therefore means
that they have less food.
Antarctic wildlife also has been affected by climate change, according
to William Fraser of Montana State University. Fraser has documented significant
declines-approximately 50 percent over the past 25 years-in populations
of Adelie penguins near Palmer Station on the Antarctic Peninsula. The
declines appear to be caused by regional changes in sea ice and snowfall,
which in turn may be related to global climate change.
Changes in temperature and moisture are expected
to have variable impacts on the forests of the high-latitude zones. Northern
treelines are likely to advance slowly into areas now occupied by tundra.
Forests whose productivity is not limited by the availability of moisture
may become more productive as the climate warms, but this may be counterbalanced
in some areas by increases in the frequency of fires and pest outbreaks.
Forests that are sensitive to drought may be adversely
affected by global warming. For example, white spruce forests in
interior Alaska have experienced severe stress from temperature-induced
drought during the past 90 years.
Some Alaskan forests have experienced a sustained infestation of spruce
bark beetles since 1992. The outbreaks, formerly limited by the cold,
have caused the death of 2.3 million acres of trees on the Kenai Peninsula
in Alaska. This is the largest loss of trees to insects ever recorded
in North America.
I hope that little introduction to Global
Warning, can motivate you to find out more about the other topics and
I hope that you will be able to speak up about this serious situation
that we are facing not only in Australia but all over the world. Remember
this is our planet, the only place so far that can holds life, so lets
all protect it the best we can. Don't be afraid to write letters to your
local MP, to find out what they are doing for the environment in our communities.