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A-Z of Global Warming: The Amazon
Introduction
This article is the first in a series of articles which
will take the reader on an alphabetic journey on global
warming, commencing with A for Amazon.
The phrase global warming is a term that has been in
common usage for some time and usually refers to the
warming of Earth's atmosphere, and which also implies
a manmade or human influence.
Earth's atmosphere is comprised of many gases, oxygen,
nitrogen, carbon dioxide and water vapour to name a
few. These gases are collectively called greenhouse
gases and they keep the Earth's temperature at a comfortable
15 degrees Celsius, without them Earth would be a chilly
- 18 degrees Celsius. Since pre-industrial times, usually
taken to be around 1750 we know from ice core records
that Co2 levels were around 280 ppm, that's 280 parts
of Co2 per million parts of air. As industrialisation
got underway mankind started to farm the land more intensely
than ever before, deforest for agriculture and settlements,
and later since around 1850 or so, burn fossil fuels
for energy and transport which have added considerably
to greenhouse gas levels, particularly Co2.
This has resulted in Co2 levels increasing to around
385 ppm, an increase of around 37% from pre-industrial
levels mainly as a result of burning fossil fuels.
How do we know this? Well, data from ice core
records that go back at least 650,000 years now show
us that Co2 levels have fluctuated naturally during
this time between 280 and 300 ppm. Co2 levels have also
been measured accurately from the top of Mauna Loa Volcano
in Hawaii since 1958, and results show an increase in
Co2 levels from 315 ppm to 385 ppm since that time.
Therefore Co2 is now at 85 ppm more than it has been
for at least 650,000 years of Earth's history. It is
a known scientific fact that higher levels of greenhouse
gases will lead to higher temperatures, which appears
to be happening now. The world has warmed by an average
of 0.74 degrees during the last 100 years or so.
As a result of this warming, polar ice has started
to decrease and melt, and so are Earth's land based
glaciers. This in turn is causing sea levels to
rise which is putting low lying islands at risk of flooding
or total submersion, and will eventually threaten more
and more of the worlds coastal cities and regions.
As Earth's atmosphere starts to warm, the warming
itself may cause further positive feedback mechanisms
to kick in. A warmer atmosphere holds more water
vapour, which is itself a powerful greenhouse gas. This
will in turn cause further warming, and so on.
Melting ice means that more sunlight is absorbed by
the surrounding "darker" water and land, meaning
further warming, and more melting ice. Methane deposits
currently held in a frozen but stable state under the
sea and under the permafrost maybe released as the oceans
warm and permafrost melts, which will cause further
warming as methane is a potent greenhouse gas etc etc.
Where better place to start this A-Z journey on
global warming than with The Amazon Rainforest, which
has an incredibly important role to play in maintaining
a balance in the Earth's climate. The Amazon is inextricably
linked to the issue of global warming and has a considerable
influence on Earth's climate.
Amazon Facts
The Amazon river basin contains the largest rainforest
on Earth and covers approximately 40% of the South American
continent. The Amazon Rainforest is located within eight
countries, Brazil contains 60% of the forest, with Colombia,
Peru, Venezuela, Ecuador, Bolivia, Guyana, Suriname
and French Guyana containing the rest.
The Amazon forest is a natural reservoir of genetic
diversity, containing the largest and most species rich
tract of tropical rainforest that exists. The Amazon
contains an amazing thirty-percent of Earth's species.
One square kilometre of Amazon can contain about 90,000
tons of living plants! It's also amazing to consider
that one in five of all the birds in the world make
the rainforest their home.
The Amazon basin is drained by the Amazon river, the
worlds second longest after the Nile and the river is
essentially the lifeline of the forest. The river is
the most voluminous on Earth.
A few hundred years ago tropical rainforests covered
as much as 12% of the Earth's land surface, but today
the figure is less than 5%. The largest stretch of rainforest
can be found in the Amazon river basin, over half of
which lies in Brazil.
Why is the Amazon so important in the context of
global warming?
The rainforest acts as a major store of Carbon and
produces enormous amounts of oxygen. The Amazon has
been referred to as "The lungs of the Earth"
because of its affect on the climate. The way this is
achieved is of course through photosynthesis, the process
by which green plants/trees use the energy from sunlight
to produce food by taking carbon dioxide (Co2) from
the air and water and converting them to carbon. The
by-product of this is oxygen.
The Amazon therefore helps recycle carbon dioxide by
turning it into oxygen, and its estimated that the Amazon
produces about 20% of this essential gas for Earth's
atmosphere.
Trees, plants and Co2
Levels of co2 in the atmosphere have been measured
since 1958 from a monitoring station located on Mauna
Loa volcano in Hawaii and they show sharp annual increases
and decreases in co2 levels, similar to the tooth on
a saw. The readings almost mimic a breath of air being
taken in and out; it's almost as if the Earth is breathing.
The readings correspond to the amount of vegetation
on the planet (most of which is contained in the Northern
Hemisphere, as the landmass there is greater), taking
in co2, and giving out oxygen. During the Northern Hemisphere
summer, when the Earth is tilted toward the sun, the
Earth's vegetation is able to photosynthesise resulting
in an uptake of co2, causing worldwide co2 levels to
drop. During winter, when the Earth's axis is tilted
away from the sun, the opposite happens causing co2
levels to rise again.
When one becomes aware of the correlation between the
Earth's vegetation and co2 levels, it is easy to understand
why the Amazon, and rainforests in general are such
an important part of Earth's ecosystem. If global warming
is to be tackled, the Amazon, and other rainforests
must be saved.
Author: Simon Rosser
A lawyer by profession,I felt inspired to write a book
entitled The A-Z of Global Warming, published in May
2008, after viewing Al Gore's documentary, An Inconvenient
Truth in Nov 2006. Based on the most upto date scientific
information,this Amazon article gives a flavour of the
books contents. To see the unique colour illustrations
from the book on various gift items, please visit the
following link - http://www.cafepress.com/globalwarmin
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