The Case of
the
Greenhouse
 The Earth's greenhouse effect is
a natural phenomenon that helps regulate the temperature of our planet. The sun heats the
earth and some of this heat, rather than escaping back to space, is trapped in the
atmosphere by clouds and greenhouse gases, such as water vapour and carbon dioxide.
Although overall mean global temperatures appear to be on the rise, regional effects can
be varied. Some regions of the world could even be experiencing a cooling trend.
Regardless, a predicted result of the human influence over global greenhouse gas
concentrations in the atmosphere is that the earth will experience a change in climate.
Global Warming Problem
Global warming is a result of the increase of thickness of the greenhouse gas layer or
increase in concentration of GHGs that are released into the atmosphere through human
activity. Increased greenhouse gas concentrations may be resulting in more heat being
trapped in the atmosphere and increasing global temperatures. Global warming leads to
climate change.
Greenhouse gases are emitted by the cars we drive, the furnaces we use to heat our homes,
and the industries that produce oil and gas, create electricity, and develop products for
the world's marketplace.
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BANGLADESH is an example of a country that has been particularly
vulnerable to the extremes of today’s climate with a low-lying coastline, high
population density, and an economy highly dependent on agriculture, the lives and
livelihoods of people are threatened by frequent cyclones and the associated effects, such
as salt water intrusion, that render agricultural lands unproductive. Between 1960 and
1991, Bangladesh was struck by 35 cyclones ( Haider et al 1991). The low topography also
makes Bangladesh prone to floods. Between 1974 and 1998, the country experienced seven
major floods (Hatin 1998). In 1998, about 68 per cent of the country’s geographical
area was flooded, affecting more than 30 million people and causing 918 fatalities
(Chaudhury 1998). Economic losses were estimated to be US$ 3.3 billion, equivalent to
eight per cent of the country’s GDP.
— Reshbha
Munjal |
Greenhouse gas emissions in relative
importance:
water vapour
carbon dioxide CO2
methane CH4
nitrous oxide N2O
chlorofluorocarbons CFCs*
hydrofluorocarbons HFCs*
and perfluorocarbons PFCs*
sulphur hexafluoride SF6
*These greenhouse gases are completely human-caused. They harm stratospheric ozone,
and so are not as directly responsible for global warming as carbon dioxide is. The
question of reducing their presence in the stratosphere is being taken care of in another
global convention, the Montreal Protocol.
These gases are particularly effective in absorbing long wave
radiation from the earth's surface and preventing heat from escaping.
Although the views and opinions of people across the world vary on
issues relating to the cause of global warming and its possible impacts, there is a common
understanding that it is a cause for major global concern and must be addressed
immediately.
— Vikramaditya Singh, Palavi
Kaushal, Maanvee Mirakhur
HUMAN ACTIVITIES RESPONSIBLE FOR THE INCREASE IN
GREEN HOUSE GASES:
- Burning fossil fuels
- Agriculture
- Biomass combustion
- Deforestation
Human activities directly add about 5000 megatonnes of carbon
dioxide to the atmosphere each year.
Since the Industrial Revolution, the world has become increasingly more reliant on fossil
fuels such as oil, natural gas and coal to provide heat for our homes, fuel for
transportation and power for industry. Combustion of these fuels produces CO2 which is a
major pollutant. |
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