what is global warming?
Global warming is the increase in the average measured temperature
of the Earth's atmosphere. The accelerated increases in global temperature, that
have been observed since the mid twentieth century, has been attributed "to the
observed increase in anthropogenic (man-made) greenhouse gas concentrations" by
the Intergovernmental Panel on Climate Change (IPCC).
Much of what we do in our day to day life results in the release
of greenhouse gases. The most prevalent of these activities result in the release
of Carbon Dioxide from burning fuels to create heat and energy. The increases of
man-made greenhouse gases has led to an enhanced greenhouse effect. This is portrayed
in the diagram below:
The Earth receives heat from the Sun and in turn reflects about
30% of this incoming heat. The remaining 70% is absorbed, warming the land, atmosphere
and ocean. Heat emitted from the surface of the earth is mostly absorbed in the
atmosphere by a combination of six greenhouse gases and clouds, and therefore does
not escape directly to space. An increase in these greenhouse gases result in an
increase in the heat absorbed in the Earth's atmosphere, and therefore an increase
in temperature.
Some of the negative potential side-effects of increasing global
temperature include:
- rises in sea level
- increases in the intensity of extreme weather events
- significant changes to the amount and pattern of precipitation; which could
lead to an expanse of tropical areas and increased pace of desertification
These changes could then potentially result in changes to agricultural
yields, modifications of trade routes, glacier retreat, species extinctions and
increases in the ranges of disease vectors.
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