This document provides information about a student presentation on climate change and greenhouse gases. It includes the names and student IDs of 10 presenters, definitions and explanations of the greenhouse effect and greenhouse gases, descriptions of the major greenhouse gases and their sources, effects of climate change, ways to reduce greenhouse gases, and conclusions about the importance of the greenhouse effect for life on Earth.
2. SERIAL NUMBER NAME STUDENT ID
1. HRIYAM DUTTA 191001001092
2. DEBARGHA PAKHIRA 191001001093
3. SREEJITA ROY 191001001096
4. ANURAG ROYCHOWDHURY 191001001097
5. SHRUTHUM DUTTA 191001001098
6. SATRAJIT KAR 191001001100
7. DEBOJYOTI KUNDU 191001001101
8. SAGNIK DEY 191001001102
9. NILANJAN DAS 191001001215
10. SANNY 191001001240
3. GREEN HOUSE EFFECT
Meaning : Progressive warming up of the earth surface due to high
concentration of man-made carbon dioxide in the atmosphere.
The trapping of the sun’s warmth in a planet’s lower atmosphere, due to the
greater transparency of the atmosphere to visible radiation from the sun than
to infrared radiation emitted from the planet’s surface.
The natural outcome is warmer atmosphere –
100 years ago CO2 – 275 ppm
In the year 2007 CO2 – 375 ppm
In the year 2040 CO2 – 450 ppm
4. Pictorial representation of Green House Effect
Green house effect is a naturally occurring phenomenon
that is responsible for heating of Earth’s surface and
atmosphere.
5. Founder of Greenhouse Effect
The Greenhouse Effect was discovered by Joseph Fourier in
1824.
First reliably experimented on by John Tyndall in 1858.
First reported quantitatively by Svante Arrhenius in 1896.
6. There are two types of greenhouse : natural and
artificial
Natural Greenhouse
It is created naturally.
The greenhouse gases in the
atmosphere trap the solar
radiations to warm the earth.
It occupies a large area.
It creates the heating effect in the
whole earth.
Artificial Greenhouse
It is created by humans.
The transparent glass allows the
radiations to pass through and
traps the radiations by not letting
them escape.
It occupies a relatively small area.
It creates the heating effect only
in a certain specified area.
7. Greenhouse Gases
“Greenhouse gases are the gases that absorb the infrared radiations and
create a greenhouse effect. For example, carbon dioxide and
chlorofluorocarbons.”
The major contributors to the greenhouses gases are factories,
automobiles, deforestation, etc. The increased number of factories and
automobiles increases the amount of these gases in the atmosphere. The
greenhouse gases never let the radiations to escape from the earth and
increase the surface temperature of the earth. This then leads to global
warming.
8. The major greenhouse gases
The effect of each greenhouse gas on Earth’s climate depends on its chemical
nature and its relative concentration in the atmosphere. Some gases have a
high capacity for absorbing infrared radiation or occur in significant
quantities, whereas others have considerably lower capacities for absorption
or occur only in trace amounts. Radiative forcing, as defined by
the Intergovernmental Panel on Climate Change (IPCC), is a measure of the
influence a given greenhouse gas or other climatic factor (such as solar
irradiance or albedo) has on the amount of radiant energy impinging upon
Earth’s surface. To understand the relative influence of each greenhouse gas,
so-called forcing values (given in watts per square metre) calculated for the
time period between 1750 and the present day are given in the next slides.
9. The major greenhouse gases
• Water vapour
Water vapour is the most potent greenhouse gas
in Earth’s atmosphere, but its behaviour is fundamentally
different from that of the other greenhouse gases. The
primary role of water vapour is not as a direct agent
of radiative forcing but rather as a climate feedback—
that is, as a response within the climate system that
influences the system’s continued activity. This
distinction arises because the amount of water vapour in
the atmosphere cannot. The warmer the surface, the
greater the evaporation rate of water from the surface.
As a result, increased evaporation leads to a greater
concentration of water vapour in the lower atmosphere
capable of absorbing infrared radiation and emitting it
back to the surface.
• Carbon dioxide
Carbon dioxide(CO2) is the most significant
greenhouse gas. Natural sources of atmospheric
CO2 include outgassing from volcanoes,
the combustion and natural decay of organic matter,
and respiration by aerobic (oxygen-using) organisms.
These sources are balanced, on average, by a set of
physical, chemical, or biological processes, called
“sinks,” that tend to remove CO2 from
the atmosphere. Significant natural sinks include
terrestrial vegetation, which takes up
CO2 during photosynthesis.
10. • Methane
Methane (CH4) is the second most important
greenhouse gas. CH4 is more potent than
CO2 because the radiative forcing produced per
molecule is greater. In addition, the infrared window
is less saturated in the range
of wavelengths of radiation absorbed by CH4, so
more molecules may fill in the region. However,
CH4 exists in far lower concentrations than CO2 in
the atmosphere, and its concentrations by volume in
the atmosphere are generally measured in parts per
billion (ppb) rather than ppm. CH4 also has a
considerably shorter residence time in the
atmosphere than CO2 (the residence time for CH4 is
roughly 10 years, compared with hundreds of years
for CO2).
• Surface-level ozone
The next most significant greenhouse gas is surface, or
low-level, ozone (O3). Surface Ozone is a result of air
pollution; it must be distinguished from naturally
occurring stratospheric O3, which has a very different
role in the planetary radiation balance. The primary
natural source of surface O3 is the subsidence of
stratospheric O3 from the upper atmosphere. In
contrast, the primary anthropogenic source of surface
O3 is photochemical reactions involving the atmospheric
pollutant carbon monoxide (CO). The best estimates of
the natural concentration of surface O3 are 10 ppb, and
the net radiative forcing due to anthropogenic
emissions of surface O3 is approximately 0.35 watt per
square metre. Ozone concentrations can rise to
unhealthy levels (that is, conditions where
concentrations meet or exceed 70 ppb for eight hours or
longer) in cities prone to photochemical smog.
11. • Nitrous oxides and fluorinated gases
Additional trace gases produced by
industrial activity that have greenhouse
properties include nitrous oxide (N2O) and
fluorinated gases (halocarbons), the latter
including CFCs, sulphur
hexafluoride, hydrofluorocarbons (HFCs),
and perfluorocarbons (PFCs). Nitrous
oxide is responsible for 0.16 watt per
square metre radiative forcing, while
fluorinated gases are collectively
responsible for 0.34 watt per square metre.
Nitrous oxides have small background
concentrations due to natural biological
reactions in soil and water, whereas the
fluorinated gases owe their existence
almost entirely to industrial sources.
12. Sources of Greenhouse gases
Power plants
Residential buildings
Road transport
Deforestation , forest degradation and land use change
Energy industry processes and losses
Commercial buildings
Cement ceramics and glass production
Livestock
Iron and steel manufacture
Agricultural soils
Chemical and petrochemical industries
Oil and gas production
Coal mining
Aviation
13. The advantages and disadvantages of greenhouse gases
Advantages of greenhouse effect
Existence of life
Maintaining earth’s temperature
Filter unwanted solar energy
Help in growing offseason crops
Solar powered water heater use
the greenhouse effect to heat
water
Maintains the water level and
restricts ice melting
Disadvantages of greenhouse effect
Sea level rise
Economic impact
Agricultural impact
Effects on aquatic systems
Effects on hydrological cycles
Health
Direct effects of temperature rise
Spread of disease
14. Causes of Greenhouse Effect
The major causes of the greenhouse effect are:
Burning of Fossil Fuels
Fossil fuels are an important part of our lives. They are widely used in transportation
and to produce electricity. Burning of fossil fuels releases carbon dioxide. With the
increase in population, the utilization of fossil fuels has increased. This has led to an
increase in the release of greenhouse gases in the atmosphere.
Deforestation
Plants and trees take in carbon dioxide and release oxygen. Due to the cutting of
trees, there is a considerable increase in the greenhouse gases which increases the
earth’s temperature.
Farming
Nitrous oxide used in fertilizers is one of the contributors to the greenhouse effect in
the atmosphere.
Industrial Waste and Landfills
The industries and factories produce harmful gases which are released in the
atmosphere. Landfills also release carbon dioxide and methane that adds to the
greenhouse gases.
15. Effects of Greenhouse effect
The main effects of increased greenhouse gases are:
Global Warming
It is the phenomenon of a gradual increase in the average temperature of the Earth’s atmosphere. The main cause for this environmental issue is the
increased volumes of greenhouse gases such as carbon dioxide and methane released by the burning of fossil fuels, emissions from the vehicles,
industries and other human activities.
Depletion of Ozone Layer
Ozone Layer protects the earth from harmful ultraviolet rays from the sun. It is found in the upper regions of the stratosphere. The depletion of
the ozone layer results in the entry of the harmful UV rays to the earth’s surface that might lead to skin cancer and can also change
the climate drastically. The major cause of this phenomenon is the accumulation of natural greenhouse gases including chlorofluorocarbons, carbon
dioxide, methane, etc.
Smog and Air Pollution
Smog is formed by the combination of smoke and fog. It can be caused both by natural means and man-made activities. In general, smog is
generally formed by the accumulation of more greenhouse gases including nitrogen and sulfur oxides. The major contributors to the formation of
smog are the automobile and industrial emissions, agricultural fires, natural forest fires and the reaction of these chemicals among themselves.
Acidification of Water Bodies
Increase in the total amount of greenhouse gases in the air has turned most of the world’s water bodies acidic. The greenhouse gases mix with the
rainwater and fall as acid rain. This leads to the acidification of water bodies. Also, the rainwater carries the contaminants along with it and falls into
the river, streams and lakes thereby causing their acidification.
Runaway Greenhouse Effect
This phenomenon occurs when the planet absorbs more radiations than it can radiate back. Thus, the heat lost from the earth’s surface is less and
the temperature of the planet keeps rising. Scientists believe that this phenomenon took place on the surface of Venus billions of years ago. This
phenomenon is believed to have occurred in the following manner: A runaway greenhouse effect arises when the temperature of a planet rises to a
level of the boiling point of water. As a result, all the water from the oceans converts into water vapor, which traps more heat coming from the sun
and further increases the planet’s temperature. This eventually accelerates the greenhouse effect. This is also called the “positive feedback loop”.
There is another scenario giving way to the runaway greenhouse effect. Suppose the temperature rise due to the above causes reaches such a high
level that the chemical reactions begin to occur. These chemical reactions drive carbon dioxide from the rocks into the atmosphere. This would heat
the surface of the planet which would further accelerate the transfer of carbon dioxide from the rocks to the atmosphere, giving rise to the runaway
greenhouse effect.
In simple words, increasing the greenhouse effect gives rise to a runaway greenhouse effect which would increase the temperature of the earth to
such an extent that no life will exist in the near future.
16. Ways to Reduce Greenhouse Gases
Reduce, Reuse, Recycle
Use Less Heat and Air Conditioning
Replace Your Light Bulbs
Drive Less and Drive Smart
Buy Energy-Efficient Products
Use Less Hot Water
Use the "Off" Switch
Plant a Tree
Get a Report Card from Your Utility Company
Encourage Others to Conserve
17. Climate Change
Global warming will lead to an increase in the evaporation of water - more water
vapour.
With more water vapour, more rain fall is expected.
But it is not evenly distributed: -
Dry areas - severe drought condition, water shortage and heat waves occurs
Wet areas - floods and avalanches (landslides)
Other problems may arise:
Destroy food crop - rice, wheat and corn
Affect animals - need to migrate
Encourage growth of weed and pests - may lead to diseases like dengue fever, cholera
which are deadly.
18. 10 Climate Change Facts Everyone Should
Know
Fact 1: The term global warming refers to the long-
term warming of the planet. The term climate change
encompasses global warming, but refers to the
broader range of changes that are happening to our
planet.
Source: NASA
Fact 2: These broader climate changes include: rising
sea levels, shrinking mountain glaciers, accelerating
ice melt in Greenland, Antarctica and the Arctic, and
shifts in flower and plant blooming times.
Source: U.S. Global Change Research Program
(USGCRP)
Fact 3: Human activity, especially greenhouse gas
emissions, is considered the dominant cause of
temperature increases.
Source: BBC News
Fact 4: The greenhouse effect refers to the way the
Earth’s atmosphere traps and absorbs solar energy.
Source: BBC News
Fact 5: The Intergovernmental Panel on Climate
Change was formed in 1988 to collect and assess
evidence on climate change. Since then, it has
produced a series of alarming climate models. Under
these models, most of the planet’s ice cover would
melt by the end of the century and trigger a cascade
of irreversible consequences, including flooding strong
enough to engulf entire cities.
Source: BBC News
Fact 6: Paleoclimatology—or the study of changes in
climate throughout Earth’s history—uses evidence
found in tree rings, ocean sediment, coral reefs, and
layers of sedimentary rocks to determine that current
warming is occurring roughly 10 times faster than the
post-ice age warming.
Source: NASA
Fact 7: By 2060, the cost of inaction on climate change
is predicted to reach a staggering $44 trillion, with the
highest anticipated GDP losses in the Middle-East,
Northern, and Sub-Saharan Africa, and South and
Southeast Asia.
Sources: CitiGPS + The Organization for Economic Co-
operation and Development
Fact 8: In 2018, there were 14 extreme-weather events
that resulted in more than $1 billion in damages.
Source: UN News
Fact 9: The average number of people exposed to
heatwaves has increased by approximately 125 million
since the beginning of the century.
Source: UN News
Fact 10: Community-led nonprofits working to fight
climate change are underfunded.
Source: Learn Library
19. International efforts to reduce
greenhouse effect
Kyoto treaty (1997) : was started to
reduce emission of greenhouse
gases by 5% of 1990s levels by
2012.
The Paris Agreement : is an
agreement within the framework of
the United Nations Framework
Convention on Climate Change
(UNFCCC) dealing with greenhouse
gases emissions mitigation,
adaptation and finance starting in
the year 2020.
20. Conclusion
Without the greenhouse effect, the Earth would not be able to support life. But if the greenhouse
effect becomes too strong, the earth will be too hot to support life. Even little too much heat could
hurt the animals, plants, and everything else on the planet. Without the gases that surround the
planet, heat would escape back into space, causing the earths average temperature to be about 60
degrees colder.
