Page 80 - Science Class 07
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and any natural forcer could achieve its effect. combusted and emit soon. It enters the
Processes in our daily lives are expelling atmosphere as fine par cles (aerosols) and
chemicals and foreign substances into the air absorbs large amounts of heat and infrared
that affect and increase the natural greenhouse radia on. The majority of black carbon in the
gases, which then absorb more energy from U.S. is emi ed from vehicles, especially diesel-
the sun. This results in global warming and fuelled ones. Wildfires, industrial and
changes the climate. residen al hea ng are also black carbon
Greenhouse Gas Emission emi ers.
Greenhouse gas emission is said to be the Black carbon is dri ed across the globe on
largest man-made climate forcer as it is so winds and can be deposited on snow or ice.
prevalent and large-scale. Greenhouse gases This darkens snow or ice, thus increasing its
occur naturally in the atmosphere and they ability to absorb heat. This, in turn, forces the
serve to absorb and radiate the sun’s heat ice to melt faster.
around the globe for the benefit of life. Industrial Produc on and Farming
Humans are now producing large amounts of Emissions from factories contribute directly to
these gasses on such a level that it has upset the greenhouse effect while runoff waste alters
energy balance. the chemical make-up of water and air.
Some of these greenhouse gases are long-lived Chemical pes cides, herbicides and fungicides
like carbon dioxide and nitrous oxide, so the used in industrial farming also wreak havoc to
damage they cause is obvious. However, short- the atmosphere. Livestock farming also
lived substances like methane s ll affect the releases large amounts of methane into the air,
energy balance as they are very potent and driving up the amount of greenhouse gases
there are so many of them. Moreover, human already in the atmosphere.
ac vity con nues to release them into the Agriculture
atmosphere.
Agriculture accounts for 14% of total green
Fossil Fuel Usage house gas emissions and with the need for
Fossil fuel burning produces, among other more agriculture to provide for our ever-
chemicals, carbon dioxide that is the primary growing needs, its impact is growing rapidly.
greenhouse gas force to climate change. In The main agricultural contributors to climate
itself it is not a par cularly warming gas, but forces include carbon released from farmland
the amount that we are emi ng into the soil by inappropriate farming and grazing
atmosphere makes it the most damaging. It prac ces.
also has a long life in the atmosphere, only fully Changes in land use for agriculture is also a
dissipa ng a er 50,000 years during which large contributor to climate change. Tillage and
me it con nues to absorb and radiate heat. water rerou ng has accelerated soil erosion,
Black Carbon soil organic ma er has been lost due to
Another by-product of fossil fuels is black chemicals, and soil itself has been altered and
carbon, which is produced when fossil fuels, polluted by chemical fer lizers, all of which
biofuels, and biomass are not properly affect the atmosphere with various emissions.
80 Science-7
