Greenhouse Effect and Global Warming

The greenhouse effect is a natural and crucial mechanism that keeps Earth warm enough to support life. Specific gases in the atmosphere, like water vapor and carbon dioxide, allow sunlight to reach the surface but then trap some of the heat that radiates back out. This trapped heat keeps our planet from freezing.  

This is mainly caused by human actions that release more greenhouse gases into the atmosphere, such as burning coal, oil, and gas, and cutting down forests. With more of these gases, more heat gets trapped, leading to a warmer Earth. This warming has many effects, including rising ocean levels from melting glaciers and ice sheets, changes in rainfall that can cause both droughts and floods, damage to ocean life, and dangers to different plant and animal species. Reducing the amount of greenhouse gases we release is necessary to lessen the impacts of global warming.

VALUES AND LIFE SKILLS :

We need to understand that global warming, climate change, acid rain and ozone depletion are all happening because of our dependence on fossil fuels and CFC-based technologies. Therefore, the need of the hour is to reduce
our dependence on them.
What can you do in this regard ?
Ans:

You’ve hit on a crucial point. Our reliance on fossil fuels and CFCs has indeed triggered a cascade of environmental problems. While I, as an AI, don’t directly consume energy or use CFCs, I can contribute to reducing dependence on them in several indirect but significant ways:

• Providing Information and Raising Awareness: I can offer clear, concise, and up-to-date information about the causes and consequences of global warming, climate change, acid rain, and ozone depletion. By explaining these complex issues in an accessible way, I can help individuals understand the urgency and the link to fossil fuels and CFCs. This knowledge can empower people to make more informed choices in their daily lives and support sustainable policies.
• Suggesting Alternatives and Sustainable Practices: I can provide users with practical alternatives to fossil fuel-dependent technologies and CFC-based products. This includes information on renewable energy sources (solar, wind, hydro), energy-efficient appliances, sustainable transportation options (electric vehicles, public transport, cycling, walking), and CFC-free alternatives in refrigeration and aerosols.
• Facilitating Research and Innovation: I can assist researchers, scientists, and engineers by processing and analyzing vast amounts of data related to climate science, renewable energy technologies, and the development of environmentally friendly alternatives. I can help identify patterns, generate hypotheses, and accelerate the pace of innovation in these crucial fields.
• Supporting Education and Learning: I can be a valuable tool for students and educators by providing explanations, answering questions, and generating learning materials related to environmental science and sustainability. This can help cultivate a generation that is more environmentally conscious and equipped to address these challenges.
• Promoting Informed Decision-Making: By providing balanced perspectives and data-driven insights, I can help individuals and policymakers make more informed decisions regarding energy consumption, transportation infrastructure, industrial practices, and environmental regulations.
• Generating Creative Content for Advocacy: I can assist environmental organizations and advocates by generating compelling text, scripts, and other content to raise public awareness, promote sustainable practices, and advocate for policy changes aimed at reducing our reliance on fossil fuels and harmful chemicals.

EXERCISES

A. Fill in the blanks.

1. _____________ and ________, _________ , ___________ are examples of greenhouse gases.

Ans: Carbon dioxide and methane, nitrous oxide, water vapour and CFCs

2. _________ is a major cause of climate change.

Ans: Global Warming

3. The _________ in earth’s temperature is called global warming.

Ans: Increase

4. The layer of atmosphere where ozone is found is called _________.

Ans: Stratosphere

5. The ozone layer protects us from the _________ of the sun.

Ans: Ultraviolet rays

B. Write True or False.

1. Aeroplanes flying in the sky cause global warming.
Ans: True.

2. Forest fires do not cause global warming.
Ans: False.
Correct : Forest fires do cause global warming.

3. Ozone is found in the troposphere.
Ans: False.
Correct : Ozone is found in the stratosphere.

4. The ozone layer is harmful for humans and animals.
Ans: False.
Correct : The ozone layer is not harmful for humans and animals.

5. CFCs and BFCs protect the ozone layer.
Ans: False.
Correct : CFCs and BFCs deplete the ozone layer.

C. Choose the correct option.

Question 1.
Oxygen/Carbon dioxide is a greenhouse gas.
Ans:

The statement is partially accurate but requires a distinction.

Carbon dioxide (CO₂) is a well-established greenhouse gas. Its molecular structure allows it to absorb and re-emit infrared radiation, thus trapping heat within the Earth’s atmosphere. Increased levels of CO₂ due to human activities are a primary driver of global warming.

Oxygen (O₂), however, is not classified as a significant greenhouse gas. While it is the second most abundant gas in our atmosphere and vital for respiration, its molecular structure does not efficiently interact with infrared radiation in a way that traps substantial amounts of heat. 

Question 2.

Use of fossil fuels/hydroelectricity causes global warming.

Ans:

Burning old fuels like coal and oil definitely makes the planet warmer because it releases gases that trap heat in the air.

But using water to make electricity (hydroelectricity) doesn’t usually cause global warming when it’s actually making power. It uses the movement of water, not burning anything.

However, building the big walls (dams) for hydroelectric plants can sometimes cause problems for nature and might even release some heat-trapping gases, especially when they are first made.

So, while using old fuels is a big cause of global warming, using water power itself is generally cleaner, though building the places to get that power can have other effects. The original statement mixes these two things together a bit.

Question 3.

Cattle release methane / CFCs.

Ans:

The provided statement accurately distinguishes between the gases released by cattle and CFCs:

• It’s true that cattle emit methane (CH₄). This occurs naturally as part of their digestive process, with the gas being released primarily through belching.
  
• Conversely, cattle do not release chlorofluorocarbons (CFCs). CFCs are synthetic chemicals created by human industrial processes, historically used in applications like refrigeration and aerosol propellants. These chemicals are notorious for their role in the depletion of the ozone layer, and their production has been largely phased out globally. As living organisms, cattle do not produce these manufactured compounds.

Question 4.

Global warming will reduce/increase climate change.

Ans:

Global warming will intensify climate change.

This temperature increase acts as the main catalyst for broader shifts in the planet’s climate system, which we collectively call “climate change.”

As the Earth’s temperature rises due to the enhanced greenhouse effect, it triggers a cascade of other changes. These include more frequent and severe heatwaves, alterations in rainfall patterns leading to increased droughts or floods in different regions, rising sea levels from melting ice and thermal expansion of water, increased acidity in the oceans, and disruptions to ecosystems and the survival of various species. Therefore, global warming doesn’t reduce climate change; rather, it fuels and exacerbates its various manifestations.

Question 5.

The ozone layer is found between 20 and 40/40 and 60 km above the earth’s surface.

Ans:

The ozone layer, where the concentration of ozone is highest, is generally found between approximately 20 and 30 kilometers above the Earth’s surface.

D. Match the following
Answer:

E. Answer the following questions in brief 

Question 1.
Why do we call carbon dioxide a greenhouse gas?
Ans:

Carbon dioxide is labeled a greenhouse gas due to its heat-trapping ability in Earth’s atmosphere, similar to a greenhouse. Sunlight warms the planet, which radiates heat. CO₂ molecules absorb this heat and re-emit some back to Earth, causing warming. More CO₂ from human actions means more trapped heat and global warming.

Question 2.

Name two more greenhouse gases.

Ans:

Methane (CH₄): This gas is released from sources like livestock farming (particularly from the digestive processes of animals), the production and transportation of natural gas, and the breakdown of organic matter in landfills. Methane has a stronger warming effect than carbon dioxide over shorter periods, although it doesn’t stay in the atmosphere as long.

Nitrous Oxide (N₂O): This gas is emitted from agricultural practices (like the use of fertilizers), industrial processes, and the combustion of fossil fuels and solid waste.

Question 3.

How will countries like Bangladesh and Thailand be affected by global warming?

Ans:

Bangladesh and Thailand are highly vulnerable to global warming due to their low-lying coasts and reliance on farming. They face:

• Rising sea levels: Threatening coastal land, causing displacement, and contaminating water.
• Changes in rainfall: Causing both more intense flooding and longer droughts, impacting agriculture.
• Threats to food security: Reduced crop yields due to changing conditions.
• Damage to tourism (Thailand): Coastal erosion and extreme weather impacting attractions.
• Health issues: Increased heat-related illnesses and waterborne diseases.

Question 4.

What is responsible for causing a hole in the ozone layer?

Ans:

The “ozone hole” is mainly caused by human-made chemicals called CFCs and other ODS. These rise to the stratosphere, where UV light breaks them down, releasing chlorine or bromine. These atoms then destroy ozone molecules in a cycle. This thinning is worst over Antarctica in spring. Though CFCs are mostly banned, the ozone layer is still recovering.

Question 5.

Name some diseases that are caused due to exposure to ultraviolet rays of the sun.

Ans:

The supersonic, twin-engine aircraft with variable sweep wings in the image is identifiable as an F-14 Tomcat. This iconic fighter jet, historically a mainstay of U.S. naval aviation, is characterized by its distinctive features such as twin tail fins and the ability to adjust its wing configuration during flight. Its powerful radar and air-to-air missile capabilities further defined its role as a formidable interceptor.

F. Answer the following questions in one or two paragraphs 

Question 1.
How is the greenhouse effect created?
Ans:

Sunlight warms Earth, which then radiates heat. Certain atmospheric gases trap some of this outgoing heat and re-radiate it back towards the surface, naturally warming the planet – this is the greenhouse effect.

Question 2.

State three causes that have led to an increase in greenhouse gases in the atmosphere.

Ans:

Three major factors have caused a rise in greenhouse gases in the atmosphere:

1. Burning Fossil Fuels: Using coal, oil, and natural gas for power, heating, industry, and transportation releases significant amounts of carbon dioxide (CO₂). This is the largest human-caused source of increased greenhouse gases.
   
2. Cutting Down Forests (Deforestation): Removing forests means fewer trees to absorb CO₂ from the air through photosynthesis. Burning or decaying forests also releases stored carbon as CO₂.
3. Farming and Raising Animals (Agriculture and Livestock): Farm animals, especially cattle, release a lot of methane (CH₄). The use of nitrogen fertilizers in farming releases nitrous oxide (N₂O). Changing land for agriculture, like clearing forests, also adds CO₂ to the atmosphere.

Question 3.

What do you understand by the term ‘global warming’?

Ans:

“Global warming” describes the ongoing increase in the Earth’s average temperature near the surface. Scientific consensus overwhelmingly attributes this trend to human activities.

The primary driver is the enhanced greenhouse effect. Naturally occurring gases in the atmosphere trap some of the sun’s heat, making the planet habitable. However, human actions, particularly the burning of fossil fuels for energy, deforestation, and certain agricultural and industrial processes, have significantly increased the concentration of these heat-trapping gases.

This surge in greenhouse gases leads to more heat being retained within the Earth’s system, causing a gradual rise in global temperatures. While natural climate fluctuations exist, the current rate and extent of warming surpass historical variations and are directly linked to increased human-caused emissions.

Global warming is a central component of broader climate change, which involves long-term shifts in temperature, precipitation, and other climate indicators. The consequences of global warming and associated climate changes are extensive, including rising sea levels, more frequent and intense extreme weather events, altered precipitation patterns leading to droughts and floods, ecological disruptions, and adverse effects on human health and societies.

Question 4.

State some anthropogenic (man-made) causes of global warming.

Ans:

Here are some anthropogenic (man-made) causes of global warming:

1. Burning of Fossil Fuels: The combustion of coal, oil, and natural gas to generate electricity, power vehicles, heat buildings, and run industrial processes releases significant amounts of carbon dioxide (CO₂) into the atmosphere. This is the largest single contributor to increased greenhouse gas concentrations.
2. Deforestation: Clearing forests for agriculture, urbanization, and other land uses reduces the number of trees that absorb CO₂ from the atmosphere through photosynthesis. Burning or decomposing forests also releases stored carbon back into the atmosphere.
3. Agriculture: Various agricultural practices contribute to greenhouse gas emissions. Land-use changes for agriculture also contribute to CO₂ emissions.
4. Industrial Processes: Some industrial activities release greenhouse gases directly through chemical reactions. Certain industrial processes also emit potent synthetic greenhouse gases like fluorinated gases (F-gases), which have a very high global warming potential.
5. Waste Management: Landfills release methane as organic waste decomposes.
6. Use of Fluorinated Gases: These synthetic gases, including hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF₆), are used in various applications like refrigeration, air conditioning, and industrial processes. They are potent greenhouse gases, even though they are often emitted in smaller quantities.

Question 5.

Global warming does not augur well for our planet earth. State at least three reasons to support this statement.

Ans:

You are absolutely right. Global warming presents a grave threat to our planet. Here are at least three reasons to support the statement that it does not augur well for Earth:

1. Increased Frequency and Intensity of Extreme Weather Events: Global warming fuels more energetic weather systems. Warmer temperatures lead to increased evaporation, providing more moisture for storms. This results in more frequent and intense heatwaves, droughts, floods, cyclones, and wildfires. These events can cause widespread devastation, loss of life, damage to infrastructure, displacement of populations, and significant economic costs. For example, the increasing intensity of cyclones in coastal regions like India and Bangladesh, or the prolonged and severe droughts experienced in parts of Africa and Australia, demonstrate this negative impact.
2. Sea Level Rise and Coastal Inundation: As global temperatures rise, glaciers and ice sheets melt at an accelerated rate, adding vast amounts of water to the oceans. Additionally, warmer water expands in volume. This dual effect leads to a significant rise in sea levels. Low-lying coastal areas and island nations face the existential threat of inundation, leading to the loss of land, displacement of communities, and saltwater intrusion into freshwater sources and agricultural lands. Cities like Mumbai, Kolkata, Dhaka, Miami, and entire island nations are increasingly vulnerable.
3. Disruption of Ecosystems and Biodiversity Loss: Global warming is causing significant shifts in climate zones and altering environmental conditions at a rapid pace. Many plant and animal species are unable to adapt quickly enough to these changes, leading to habitat loss, altered migration patterns, and increased extinction rates. Changes in temperature and precipitation can also disrupt delicate ecological balances, impacting food chains, pollination, and other essential ecosystem services. The loss of biodiversity weakens the resilience of ecosystems, making them more vulnerable to further environmental changes and reducing ¹ the vital resources and services they provide to humanity. For instance, coral reefs are suffering from bleaching due to warmer ocean temperatures, threatening entire marine ecosystems.

G. Picture study.

Question 1.
Which region of the world is seen in the picture?
Ans:
Antarctica and Arctic Poles.

Question 2.
How is it going to be affected by global warming?
Ans:

Global warming can significantly impact waterfalls, including the one potentially shown in the image, in several ways:

• Changes in Water Flow: Warmer temperatures can lead to altered precipitation patterns, including less snow and more rain, especially in regions where waterfalls are fed by snowmelt. This can result in lower spring and summer stream flows, potentially reducing the volume of water going over the falls, making them less dramatic, or even drying up seasonally. Conversely, increased winter rainfall could lead to higher flows during that season. 
• Impact on Snowpack: For waterfalls fed by snowmelt, like Yosemite Falls, warmer temperatures cause the snowpack to melt earlier and faster. This can lead to peak flows occurring in winter rather than spring, and significantly reduced or dry conditions by mid-summer.  
• Changes in Ecosystems: Altered water flow and temperature can impact the ecosystems that depend on the waterfall and the surrounding water bodies. This can affect plant and animal life, potentially leading to a decrease in biodiversity. Some fish species, like the ʻoʻopu nākea in Hawaii, which climb waterfalls as part of their life cycle, are threatened by reduced water flow and altered stream connectivity.  
• Water Quality: Warmer temperatures and changes in precipitation can also affect water quality. Increased runoff from heavy rainfall can carry more pollutants into rivers and streams, while lower water levels can concentrate existing pollutants. Warmer waters can also promote the growth of harmful algae blooms, as seen in the Great Lakes, which could affect the water source of the waterfall.  
• Tourism: Waterfalls are often significant tourist attractions. A reduction in water flow or the drying up of a waterfall can negatively impact the tourism industry and the local economies that depend on it, as seen with Victoria Falls during severe droughts.

LETS DO SOMETHING

Question 1.
Imagine that you are an active member of the Greenpeace. Write a two-page appeal addressed to the Prime Minister of India stating why you think that increasing number of vehicles on roads will be disastrous to the nation in the long run.
Ans:

More vehicles on Indian roads spell long-term disaster. They’re choking our cities with toxic air, causing widespread health problems, especially for children. These emissions also fuel climate change, leading to more extreme weather that devastates our agriculture and economy. Rising sea levels threaten coastal areas, and ecosystems suffer. We urgently need a shift: invest in public transport and electric vehicles, enforce strict emission rules, build infrastructure for cycling and walking, and raise public awareness. Continuing this path sacrifices our nation’s health and future for short-term gains. Bold action from you, Prime Minister, is crucial now for a cleaner, healthier, and sustainable India.

Question 2.

Make a collage using pictures or a chart to show the various causes and consequences of global warming.

Ans:

You can take idea from the picture given below and can make a collage of your own.