Global warming is related to the more general phenomenon of
climate change, which refers to changes in the totality of attributes that
define climate. In addition to changes in air temperature,
climate change involves changes to precipitate patterns, winds, ocean currents,
and other measures of Earth’s climate. Normally, climate change can be viewed
as the combination of various natural forces occurring over diverse timescales.
Since the advent of human civilization, climate change has involved an
“anthropogenic,” or exclusively human-caused, element, and this anthropogenic
element has become more important in the industrial period of the past two
centuries. The term global warming is used specifically to refer to any
warming of near-surface air during the past two centuries that can be traced to
anthropogenic causes.
Human activities have contributed to a number of the
observed changes in climate. This contribution has principally been through the
burning of fossil fuels, which has led to an increase in the
concentration of GHGs in the atmosphere. Another human influence on the
climate are carbon dioxide and sulphur dioxide emissions, which are a
precursor to the formation of sulfate
aerosols in the atmosphere.
The atmosphere allows
most of the visible light from the Sun to
pass through and reach the Earth’s surface. As the Earth’s surface is heated by sunlight,
it radiates part of this energy back toward space as infrared
radiation. This radiation, unlike visible light, tends to be absorbed by
the greenhouse gases
in the atmosphere,
raising its temperature. The heated atmosphere in turn radiates infrared
radiation back toward the Earth’s surface.
The effects of global
warming are the environmental and social changes caused (directly or
indirectly) by human emissions of greenhouse
gases. There is a scientific consensus that
climate change is occurring, and that human activities are the primary driver.
Many impacts of climate change have already been observed, including glacier retreat, changes in the
timing of seasonal events (e.g., earlier flowering of plants), and
changes in agricultural productivity. Greenhouse gases include Chlorofluocarbon
(CFC),Carbon-dioxide, Nitrogen oxides and Methane.
Carbon dioxide is used as a refrigerant, in fire
extinguishers, for inflating life rafts and life jackets, blasting coal,
foaming rubber and plastics, promoting the growth of plants in greenhouses,
immobilizing animals before slaughter, and in carbonated beverages.
Prolonged exposure of Carbon dioxide to Humans for more than
5 percent concentration can cause unconsciousness and death.
CFC is responsible for making a hole in the ozone layer in
the stratosphere.
Methane is one of the hydrocarbon and is used as fuel for
various purposes.
Nitrogen oxides are used for preservation of blood samples.
Scientific understanding of the cause of global warming has
been increasing. In its fourth assessment (AR4 2007) the
Intergovernmental Panel on Climate Change (IPCC)
reported that scientists were more than 90% certain that most of global warming
was being caused by increasing concentrations of greenhouse
gases produced by human activities(anthropogenic). In
2010 that finding was recognized by the national science academies of all major
industrialized nations.
Developed countries have developed greenhouse technology to
reduce the emission of greenhouse gases in the atmosphere.and even the
developing countries like India and China are in the process to adopt this
technology.
Through
this article I would like to request all the readers to do their part of bit to
reduce the effects of global warming.
About the Author:
The Author is Ms. Preeti Bhardwaj, Meenakshi World School
www.meenakshiworldschool.com
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