3.2 Effect of Greenhouse Gases on Global Warming
and Climate Change
The authors concur with Michael Robert [2] that there are some effects of greenhouse gases on global warming before human activities and after human activities.
Before the human activity, it is assumed that (a) sunlight penetrates the atmosphere and warms the earth’s surface; (b) the earth’s surface radiates heat to the
atmosphere, and some escapes into space; and (c) the natural activities such as
volcanic activity and natural forest fires would emit greenhouse gases in the atmosphere, and so greenhouse gases in the atmosphere absorb some of the heat and trap
it near the earth’s surface keeping the earth warm enough to sustain life. So the main
reason for the earth’s warming is due to the greenhouse effect. A microcosm of this
balance can be seen in the relationship between humans, animals, and trees and
plants. Humans and animals take in oxygen and release carbon dioxide (CO 2 ), while
trees and other plants take in carbon dioxide and release oxygen, thereby creating a
balance in nature.
After the human activity, it is assumed that (a) sunlight still penetrates the
atmosphere and warms the earth’s surface; (b) the earth’s surface still radiates heat
to the atmosphere, and some escapes into space as usual; and (c) the natural activities
such as volcanic activity and natural forest fires would still emit greenhouse gases in
the atmosphere, but, due to increased human activity (from electricity, transportation, industry, and population increase), large amounts of CO 2 and other greenhouse
gases have been released into the atmosphere, and also as trees get cut down and
deforested, there are less resources using up the CO 2 , causing levels to rise beyond
natural levels. So, the excess CO 2 and other greenhouse gases trap the extra radiation
near the earth’s surface, causing global temperatures to rise or global warming due to
in-balance of carbon intake and output. In turn, the climate on the earth is changed
due to global warming. There is a chain reaction.
The definitions of greenhouse gases and other technical terms have been introduced previously. The main contributor to the greenhouse effect is carbon dioxide .
Following carbon dioxide is methane gas (CH 4 ) and nitrous oxide (N 2 O) and the
halocarbons as the leading greenhouse gases. Figure 1.3 shows the major climate
changing agents of greenhouse gases and their radiative forcing (W m
À2
), showing
their emission ability to retain heat and their great amounts on the earth’s surface
[4]. Carbon dioxide has the greatest amount where it absorbs heat at a radiative
forcing above 1.5 W m
À2 of increased and retained solar radiation at the earth’s
surface. Although the halocarbons, methane, and nitrous oxide have a greater
warming potential than carbon dioxide, the larger quantity of carbon dioxide has a
greater impact [28]. Ozone depends on the location. In the troposphere where people
live is a greenhouse gas where it absorbs heat; however, ozone in the stratosphere
actually absorbs UV radiation and holds back the radiation from hitting the earth’s
surface, thereby keeping the earth cooler. Water does not affect the warming of the
earth too much since the concentration levels are fairly constant. Land use goes both
8
L. K. Wang et al.
and Climate Change
The authors concur with Michael Robert [2] that there are some effects of greenhouse gases on global warming before human activities and after human activities.
Before the human activity, it is assumed that (a) sunlight penetrates the atmosphere and warms the earth’s surface; (b) the earth’s surface radiates heat to the
atmosphere, and some escapes into space; and (c) the natural activities such as
volcanic activity and natural forest fires would emit greenhouse gases in the atmosphere, and so greenhouse gases in the atmosphere absorb some of the heat and trap
it near the earth’s surface keeping the earth warm enough to sustain life. So the main
reason for the earth’s warming is due to the greenhouse effect. A microcosm of this
balance can be seen in the relationship between humans, animals, and trees and
plants. Humans and animals take in oxygen and release carbon dioxide (CO 2 ), while
trees and other plants take in carbon dioxide and release oxygen, thereby creating a
balance in nature.
After the human activity, it is assumed that (a) sunlight still penetrates the
atmosphere and warms the earth’s surface; (b) the earth’s surface still radiates heat
to the atmosphere, and some escapes into space as usual; and (c) the natural activities
such as volcanic activity and natural forest fires would still emit greenhouse gases in
the atmosphere, but, due to increased human activity (from electricity, transportation, industry, and population increase), large amounts of CO 2 and other greenhouse
gases have been released into the atmosphere, and also as trees get cut down and
deforested, there are less resources using up the CO 2 , causing levels to rise beyond
natural levels. So, the excess CO 2 and other greenhouse gases trap the extra radiation
near the earth’s surface, causing global temperatures to rise or global warming due to
in-balance of carbon intake and output. In turn, the climate on the earth is changed
due to global warming. There is a chain reaction.
The definitions of greenhouse gases and other technical terms have been introduced previously. The main contributor to the greenhouse effect is carbon dioxide .
Following carbon dioxide is methane gas (CH 4 ) and nitrous oxide (N 2 O) and the
halocarbons as the leading greenhouse gases. Figure 1.3 shows the major climate
changing agents of greenhouse gases and their radiative forcing (W m
À2
), showing
their emission ability to retain heat and their great amounts on the earth’s surface
[4]. Carbon dioxide has the greatest amount where it absorbs heat at a radiative
forcing above 1.5 W m
À2 of increased and retained solar radiation at the earth’s
surface. Although the halocarbons, methane, and nitrous oxide have a greater
warming potential than carbon dioxide, the larger quantity of carbon dioxide has a
greater impact [28]. Ozone depends on the location. In the troposphere where people
live is a greenhouse gas where it absorbs heat; however, ozone in the stratosphere
actually absorbs UV radiation and holds back the radiation from hitting the earth’s
surface, thereby keeping the earth cooler. Water does not affect the warming of the
earth too much since the concentration levels are fairly constant. Land use goes both
8
L. K. Wang et al.