Greenhouse Gases: Composition, Sources, Environmental Impact and Mitigation Strategies
Greenhouse Gases: Composition, Sources, Environmental Impact and Mitigation Strategies
St. Joseph College of Teacher Education
for Women, Ernakulam
Abstract:
Keywords: Global Warming, Greenhouse gases, Carbon dioxide, Methane, Nitrous Oxide, Fluorinated Gases, GWP
Introduction
Weather is what's happening outside right now, like if
it's sunny or raining. Climate is what the weather
is usually like in a certain place over a long time. So, weather changes a lot,
but climate is more predictable.
Climate change is when the average weather patterns in an area change significantly over decades or longer. This
has happened naturally throughout Earth's history, but now human activities are speeding it up. There are natural
factors, like changes in Earth's orbit, that
influence climate over thousands of years, leading to things like ice ages. But
right now, humans are causing climate
change by releasing greenhouse gases, mainly from burning fossil fuels like coal, oil, and gas. These gases
trap heat in the atmosphere, making the Earth warmer. We've already seen some warming, but it's the future that
worries scientists. If we keep emitting greenhouse
gases at the current rate, the Earth could warm by 1.4 to 5.8 degrees Celsius
by the year 2100, according to experts.
This might not sound like much, but compared to natural changes over the past 1000 years, it's a big deal. It could lead to more extreme weather,
rising sea levels,
and other problems that affect
people and ecosystems worldwide. So, it's important to take
action to reduce greenhouse gas emissions and slow down climate change. This
article will give you an idea about
some important greenhouse gases, their effect on environment and mitigation strategies.[1]
Definition of keywords
Global Warming: Gradual increase
in Earth’s average
temperature due to human activities, Primarily the release
of greenhouse gases into the atmosphere.
Greenhouse Gases: Gases that trap heat in the Earth’s atmosphere,
contributing to the greenhouse
effect. Examples include carbon dioxide (CO2), methane (CH4),
nitrous oxide (N2O), and fluorinated
gases.
Carbon Dioxide
(CO2): A colorless, odorless greenhouse gas emitted primarily
through the combustion of fossil fuels
and deforestation,
contributing significantly to global
warming.
Methane (CH4): A potent greenhouse gas released during natural processes
like decomposition in wetlands,
as well as human
activities such as livestock farming and fossil
fuel extraction.
Nitrous Oxide (N2O): A greenhouse gas produced
by agricultural and industrial activities, as well as natural processes like microbial action in
soils and oceans.
Fluorinated Gases: Synthetic gases
used in various industrial
applications such as refrigeration, air conditioning, and electronics,
with high global warming potentials.
GWP (Global
Warming Potential): A measure of how much a given mass of greenhouse gas contributes to global
warming over a specified time period, compared to carbon dioxide.[7]
Greenhouse effect
The greenhouse effect is like a blanket around the
Earth, trapping heat from the sun and keeping
our planet warm enough for life. Scientists have known about this for a
long time, starting with Jean Baptiste-Joseph de Fourier in 1827. He compared
it to a greenhouse where
plants grow.
Later, John Tyndall
and Svante Arrhenius discovered that gases like water vapor, carbon
dioxide, and methane
trap heat in the atmosphere.
Over the years, humans have been adding more of these
gases by burning fossil fuels and other activities.
This extra trapping of heat is causing the Earth's temperature to rise, leading
to global warming. We can see the
effects of this through satellite observations, which show how these gases absorb heat in the atmosphere. So, when we talk about the
greenhouse effect, it's about how
certain gases in our atmosphere keep
heat from escaping into space, much
like how a blanket keeps us warm at
night. But when we add too many of these gases, like carbon dioxide from burning fuels, it's like adding an extra layer to that blanket, making the Earth warmer than it should
be.[2]
Greenhouse gases:
Gases that trap heat in the atmosphere are called
greenhouse gases. This section provides information
on emissions and removals of the main greenhouse gases to and from the atmosphere.
Carbon
dioxide (CO2): Carbon dioxide enters the
atmosphere through burning fossil fuels (coal,
natural gas, and oil), solid waste, trees and other biological
materials, and also as a result of certain chemical reactions (e.g., cement
production). Carbon dioxide is removed from the atmosphere (or "sequestered")
when it is absorbed by plants as part of the biological carbon cycle.
Methane (CH4): Methane
is emitted during the production and transport of coal, natural gas, and oil. Methane emissions also result from
livestock and other agricultural practices, land use, and by the decay of
organic waste in municipal solid waste landfills.
Nitrous oxide (N2O): Nitrous oxide is emitted during agricultural, land use, and industrial activities; combustion of fossil
fuels and solid waste; as well
as during treatment of wastewater.
Fluorinated gases: Hydrofluorocarbons, perfluorocarbons, sulfur hexafluoride, and nitrogen trifluoride are synthetic, powerful
greenhouse gases that are emitted from a variety of household, commercial, and industrial applications and processes. Fluorinated gases (especially hydrofluorocarbons) are sometimes used as substitutes for stratospheric ozone-depleting substances (e.g., chlorofluorocarbons, hydro
chlorofluorocarbons, and halons). Fluorinated gases are typically emitted in smaller quantities than other
greenhouse gases, but they are potent greenhouse
gases. With global warming potentials (GWPs) that typically range from
thousands to tens of thousands, they
are sometimes referred to as high-GWP (global warming potential) gases because,
for a given amount of mass,
they trap substantially more heat than CO2.[2]
Each gas's effect on climate
change depends on three main factors:
1) How
abundant are greenhouse gases in the atmosphere?
Concentration, or abundance, is the amount of a
particular gas in the air. Larger emissions of
greenhouse gases lead to higher concentrations in the atmosphere. Greenhouse gas concentrations are measured in parts per
million, parts per billion, and even parts per trillion. One part per million is equivalent to one drop of water
diluted into about 13 gallons of liquid (roughly the fuel tank of
a compact car).
2) How
long do greenhouse gases stay in the atmosphere?
Each of these gases can remain in the atmosphere for
different amounts of time, ranging from a few
years to thousands of years. All of these gases remain in the atmosphere long
enough to become well mixed, meaning
that the amount that is measured in the atmosphere is roughly the same
all over the world,
regardless of the source
of the emissions.
3) How strongly
do greenhouse gases impact the atmosphere?
Some gases are more effective than others at making the
planet warmer and "thickening the Earth's
atmospheric blanket."
For each greenhouse gas, a Global Warming Potential
(GWP) was developed
to allow comparisons of the global warming impacts
of different gases. Specifically, it is a measure of how much energy the emissions of 1 ton of a gas will absorb over
a given period of time, typically a
100-year time horizon, relative to the emissions of 1 ton of carbon dioxide (CO2). Gases with a higher GWP absorb more
energy, per ton emitted, than gases with a lower GWP, and thus contribute more to warming
Earth.[2]
The chemical compositions of the greenhouse gases
mentioned are as follows:
1. Carbon dioxide
(CO2): One carbon
atom bonded to two oxygen
atoms.
Chemical formula:
CO2
2. Methane (CH4): One carbon atom bonded to four hydrogen
atoms. Chemical formula: CH4
3. Nitrous oxide
(N2O): Two nitrogen atoms bonded to one oxygen
atom. Chemical formula:
N20
4. Fluorinated
gases: This category includes various fluorine-containing compounds such as hydrofluorocarbons (HFCs), perfluorocarbons (PFCs),
sulfur hexafluoride (SF6),
and nitrogen trifluoride (NF3). Each compound
has its own specific chemical
composition. For example:
a) Hydrofluorocarbons (HFCs) consist of hydrogen, fluorine,
and carbon atoms.
b) Perfluorocarbons
(PFCs) consist of carbon and fluorine atoms.
c) Sulfur hexafluoride (SF6)
consists of sulfur and fluorine atoms.
d) Nitrogen trifluoride (NF3)
consists of nitrogen
and fluorine atoms.
Each of these gases contributes to the greenhouse effect
to varying degrees[2]
Global Warming Potential (GWP)
The Global Warming Potential (GWP) is a measure of how
much heat a greenhouse gas traps in the
atmosphere over a specific time period, relative to carbon dioxide (CO2), which is assigned a value of 1
.Here are approximate GWPs for different gases:
Carbon dioxide (CO2): GWP = 1 (baseline) Methane (CH4): GWP = 28-36
over 100 years
Nitrous oxide (N2O): GWP = 265-298 over 100
years
Fluorinated gases (e.g.,
hydrofluorocarbons, perfluorocarbons, sulfur hexafluoride): GWPs vary widely,
ranging from hundreds to thousands, depending on the specific
gas and time horizon.
These values represent
the relative potency of these gases in contributing to global warming over a specified
period compared to CO2.[8]
Main sources of greenhouse gas emissions
Carbon dioxide
The main sources
of CO2 emissions
are:
Transportation: The combustion of fossil fuels such as gasoline and diesel to
transport people and goods is the
largest source of CO2 emissions. This category includes domestic
transportation sources such as highway and passenger vehicles,
air travel, marine
transportation, and rail
Electricity: Electricity is a key source of energy and is used to power homes,
business, and industry. The types of
fossil fuel used to generate electricity emit different amounts of CO2.
To produce a given amount of
electricity, burning coal will produce more CO2 than natural gas or oil.
Industry: Many industrial processes
emit CO2 through fossil fuel consumption. Several
processes also produce CO2
emissions through chemical reactions that do not involve combustion, and examples include the production of mineral
products such as cement, the production of metals such as iron and steel, and the production of chemicals.
Carbon dioxide is constantly being exchanged among the atmosphere, ocean, and land surface as it
is both produced and absorbed by many microorganisms, plants, and animals.
Emissions and removals of CO2
by these natural processes, however, tend to balance over time, absent anthropogenic impacts. Since the
Industrial Revolution began around 1750, human activities have contributed substantially to climate
change by adding CO2 and other heat-trapping gases to the atmosphere
Methane
The main sources of methane emissions are:
Agriculture: Domestic
livestock such as cattle, swine, sheep, and goats produce CH4 as
part of their normal digestive
process. Also, when animal manure is stored or managed in lagoons or holding
tanks, CH4 is produced. Because
humans raise these animals for food and other products,
the emissions are considered
human-related.
LULUCF: Emissions of CH4 also occur as a result of land use and
land management activities in the Land Use, Land-Use Change,
and Forestry sector (e.g. forest and grassland
fires, management of flooded
lands such as reservoirs, decomposition of organic matter in coastal wetlands).
Energy and
Industry: Natural gas and petroleum systems are the second largest source of
CH4 emissions Methane
is emitted to the atmosphere during the production, processing, storage, transmission, distribution, and use of
natural gas, and the production, refinement, transportation, and
storage of crude oil. Coal mining is also a source of CH4 emissions.
Waste from
Homes and Businesses: Methane is generated in
landfills as waste decomposes and in
the treatment of wastewater. Landfills are the third-largest source of CH4
emissions in the United States.
Methane is also generated from domestic and industrial wastewater treatment and from composting and anaerobic digestion.
Methane is also emitted from a number of natural
sources. Natural wetlands that are not managed
or changed by human activity are the largest source, emitting CH4
from bacteria that decompose organic
materials in the absence of oxygen. Reservoirs and ponds with high organic
matter and low oxygen levels also produce
methane through the microbial breakdown of organic matter.
Smaller sources include
termites, oceans, sediments, volcanoes, and wildfires.
Nitrous oxide
The main sources of Nitrous oxide
emissions are:
Agriculture: Nitrous
oxide can result from various agricultural soil management activities, such as application of synthetic and organic
fertilizers and other cropping practices, the management of manure, or burning of agricultural residues. Agricultural
soil management is the largest source of
N2O emissions. Emissions of N2O also occur as a result of
land use and land management activities
in the Land Use, Land-Use Change, and Forestry sector (e.g. forest and
grassland fires, application of
synthetic nitrogen fertilizers to urban soils (e.g., lawns, golf courses) and
forest lands, etc.).
Fuel
Combustion:
Nitrous oxide is emitted when fuels are burned. The
amount of N2O emitted from
burning fuels depends on the type of fuel and combustion technology,
maintenance, and operating practices.
Industry: Nitrous oxide is generated as a byproduct during the production of
chemicals such as nitric acid, which
is used to make synthetic commercial fertilizer, and in the production of
adipic acid, which is used to make
fibers, like nylon, and other synthetic products. Nitrous oxide is also emitted
from use in other applications such as anesthesia and semiconductor manufacturing.
Waste: Nitrous oxide is also generated
from treatment of domestic wastewater during nitrification and denitrification of the nitrogen
present, usually in the form of urea, ammonia, and proteins.
Nitrous oxide emissions occur naturally through many
sources associated with the nitrogen cycle,
which is the natural circulation of nitrogen among the atmosphere, plants,
animals, and microorganisms that live
in soil and water. Nitrogen takes on a variety of chemical forms throughout the nitrogen cycle, including N2O. Natural emissions of N2O are mainly from bacteria
breaking down nitrogen in soils and the oceans. Nitrous oxide is removed from
the atmosphere when it is absorbed by
certain types of bacteria or destroyed by ultraviolet radiation or chemical reactions.
Fluorinated gases
The main sources of Fluorinated gas emission are:
Substitution for Ozone-Depleting Substances: Hydrofluorocarbons are used as refrigerants, aerosol propellants, foam blowing agents,
solvents, and fire retardants. The major emissions source of these compounds is their use as refrigerants—for
example, in air conditioning systems in both vehicles and buildings. These chemicals were developed as a replacement for chlorofluorocarbons (CFCs) and hydro chlorofluorocarbons (HCFCs)
because they do not deplete the stratospheric ozone layer.
CFCs and HCFCs are also greenhouse
gases; however, their contribution is
not included here because they are being phased out under an international agreement called the Montreal Protocol.
HFCs are potent greenhouse gases with high GWPs, and they are released
into the atmosphere during manufacturing processes
and through leaks, servicing, and disposal of equipment in which they are used. Newly developed
hydrofluoroolefins (HFOs) are a subset of HFCs and are characterized by
short atmospheric lifetimes and lower GWPs. HFOs are currently being introduced as refrigerants, aerosol
propellants and foam blowing
agents.
Industry: Perfluorocarbons are produced
as a byproduct of aluminum
production and are used in the
manufacturing of semiconductors. PFCs generally have long atmospheric lifetimes and GWPs near 10,000. Sulfur hexafluoride is
used in magnesium processing and semiconductor
manufacturing, as well as a tracer gas for leak detection. Nitrogen
trifluoride is used in semiconductor manufacturing. HFC-23 is
produced as a byproduct of HCFC-22 production and is used in semiconductor manufacturing.
Transmission
and Distribution of Electricity: Sulfur
hexafluoride is used as an insulating gas in
electrical transmission equipment, including circuit breakers. The GWP
of SF6 is 23,500 making it the most
potent greenhouse gas that the Intergovernmental Panel on Climate Change has evaluated.
Consequences of greenhouse effect
Greenhouse Effect Cause: Human activities like industry, agriculture, and transport increase
greenhouse gases.
Consequences on Environment
1. Glacial Melting:
Reduces albedo, raises
sea levels, releases
methane.
2. Coastal Flooding:
Global sea level rise threatens millions by 2100.
3. Stronger Hurricanes: Intensified by higher
sea temperatures.
4. Species Migration: Changing climates force animals and humans to relocate.
5. Desertification: Soil degradation destroys
fertile areas, impacting
food security.
6. Agricultural/Livestock Impact:
Alters growing seasons, increases pests, affects livestock
health.
Consequences of Human
Health
1. Food
shortages: Climate change, driven by the greenhouse effect, can lead to
declines in agricultural production,
particularly affecting regions like sub-Saharan Africa and South Asia.
2. Spread
of diseases and pandemics: Global warming can facilitate the spread of
infectious diseases such as
malaria, cholera, and dengue to new areas of the planet. This can lead to health crises and necessitate migration
due to economic challenges. Additionally, extreme heat exacerbates cardiovascular and respiratory
problems. In regions like Spain, native
species have already shown cases of diseases like Dengue and Zika, previously not common, with the potential for re-emergence of eradicated
diseases like malaria if temperatures
continue to rise. [8]
Reduction opportunities for greenhouse gases
Carbon
dioxide
Energy
Efficiency: Improving
the insulation of buildings, traveling in more fuel-efficient vehicles,
and using more efficient electrical appliances
are all ways to reduce energy use, and thus CO2
emissions.
Energy Conservation: Reducing personal
energy use by turning off lights and electronics when not
in use reduces electricity demand. Reducing distance traveled in vehicles
reduces petroleum consumption. Both are ways to reduce energy CO2 emissions through conservation.
Fuel Switching: Producing more energy
from renewable sources and using fuels with lower carbon
contents are ways to reduce
carbon emissions.
Carbon
Capture and Sequestration (CCS): Carbon dioxide capture and sequestration is a set of technologies that can potentially
greatly reduce CO2 emissions from new and existing coal- and gas-fired power plants, industrial
processes, and other stationary sources of CO2. For example, a CCS project might capture CO2
from the stacks of a coal-fired power plant before it enters the atmosphere, transport the CO2
via pipeline, and inject the CO2 deep underground at a carefully selected and suitable subsurface geologic
formation, such as a nearby abandoned oil field, where it is securely stored.[4]
Methane
Industry: Upgrading
the equipment used to produce, store, and transport oil and natural gas can reduce many of the leaks that contribute
to CH4 emissions. Methane from coal mines can also be captured and used for energy.
Agriculture: Methane
from manure management practices can be reduced and captured by altering
manure management strategies. Additionally, modifications to animal feeding
practices may reduce
emissions from enteric
fermentation.
Waste from Homes
and Businesses: Capturing landfill CH4 for destruction in a flare or conversion to renewable energy
are both effective emission reduction strategies
Additionally, managing waste at a higher tier on the
waste management hierarchy can reduce CH4 generation at landfills.
[3][4]
Nitrous oxide:
Agriculture: The
application of nitrogen fertilizers accounts for the majority of N2O
emissions in the United States.
Emissions can be reduced by reducing nitrogen-based fertilizer applications and applying these fertilizers
more efficiently, as well as modifying
a farm's manure
management practices.
Fuel
Combustion:
Nitrous oxide is a byproduct of fuel combustion, so
reducing fuel consumption in motor vehicles and secondary sources can reduce emissions.
Additionally, the introduction of pollution control
technologies (e.g., catalytic
converters to reduce exhaust
pollutants from passenger cars) can
also reduce emissions of N2O.
Industry: Nitrous
oxide is generally emitted from industry through fossil fuel combustion, so technological upgrades and fuel switching
are effective ways to
reduce industry emissions of N2O.
Production of nitric
acid and adipic
acid result in N2O emissions that can be reduced through
technological upgrades and use of
abatement equipment.[3][4]
Fluorinated gases:
Substitution of Ozone-Depleting Substances in Homes
and Businesses: Refrigerants used
by businesses and residences emit
fluorinated gases. Emissions can be reduced by better handling of these gases and use of substitutes with
lower global warming potentials and other technological improvements.
Industry: Industrial
emitters of fluorinated gases can reduce emissions by adopting fluorinated gas capture and destruction processes, optimizing production to minimize emissions, and replacing these gases with alternatives.
Electricity Transmission and Distribution: which promotes leak detection and repair, use of recycling equipment, and consideration
of alternative technologies that do not use SF6.
Transportation: Hydrofluorocarbons (HFCs) are released through the leakage of
refrigerants used in vehicle air-conditioning systems. Leakage can be reduced
through better system components
and through the use of alternative refrigerants with lower global warming
potentials than those presently used.
Providing incentives for manufacturers to produce vehicles with lower HFC emissions.[4]
Conclusion
The purpose of reading this article is to gain a
comprehensive understanding of the different
greenhouse gases, their sources, environmental impacts, and mitigation
strategies. By delving into these key
aspects, readers can equip themselves with the knowledge needed to contribute
to efforts aimed at addressing
climate change and promoting sustainability. Whether for academic study, policymaking, or personal interest,
this article serves as a valuable resource for anyone seeking to comprehend the complex dynamics
of greenhouse gas emissions and their implications for the planet. The diverse
array of greenhouse gases, including carbon dioxide, methane, nitrous
oxide, and fluorinated gases, play crucial roles in
shaping Earth’s climate.
While these gases are naturally occurring, human
activities have significantly amplified their
presence in the atmosphere through activities such as burning fossil
fuels, deforestation, and industrial
processes. This heightened concentration of greenhouse gases has led to
detrimental impacts on the
environment, including rising global temperatures, altered precipitation
patterns, accelerated sea-level
rise, and disruptions to ecosystems and biodiversity. However, there is hope. Through concerted efforts, we can mitigate the effects of greenhouse gas emissions.
Strategies such
as transitioning to renewable energy
sources, implementing energy-efficient technologies,
promoting sustainable land-use practices, and adopting policies to limit
emissions can help curb the
trajectory of climate change and safeguard the planet for future generations.
It is imperative that we act swiftly
and decisively to address the challenges posed by greenhouse gases. By embracing sustainable practices
and pursuing innovative solutions, we can mitigate the impacts of climate change and foster
a healthier, more resilient planet
for all.[6]
References
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of Greenhouse Gases. Retrieved from https://www.epa.gov/ghgemissions/overview-greenhouse-gases
[2] Wallington, T. J., Srinivasan, J., Nielsen, O. J., & Highwood, E. J. Environmental and Ecological Chemistry: Greenhouse Gases and
Global Warming. Publisher.
[3]U.S. Environmental Protection
Agency. Overview of Greenhouse Gases - Methane. Retrieved February 27, 2024, from https://www.epa.gov/ghgemissions/overview-greenhouse- gases#methane
[4] Stocker, T.F., Qin, D., Plattner, G.K., Tignor, M., Allen, S.K., Boschung, J., Nauels, A., Xia, Y., Bex, V., & Midgley, P.M. (Eds.).
(2021). Climate Change 2021: The Physical Science
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Contribution of Working Group I to the Sixth Assessment Report
of the Intergovernmental Panel on Climate Change. Cambridge University Press.
[5] IPCC. (2013). Climate Change 2013: The Physical Science Basis.
Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel
on Climate Change.
In T.F. Stocker, D. Qin, G.K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex, &
P.M. Midgley (Eds.), Cambridge
University Press.
[6 ] Poulopoulos, S. G., &
Inglezakis, V. J. (Eds.). (2016).
Environment and Development: Basic Principles, Human Activities, and Environmental Implications
[7] Glossary: Global-warming potential (GWP) retrieved from https://ec.europa.eu/eurostat/statistics-explained/index.php?title=Glossary:Global-
warming_potential_(GWP)#:~:text=Global%2Dwarming%20potential%2C%20abbreviated%20a s,those%20calculated%20over%20100%20years.
[8] 
Iberdrola.
(n.d.). Greenhouse Effects: Consequences and Impacts. Retrieved from https://www.iberdrola.com/sustainability/greenhouse-effects-consequences-and- consequences.
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