All questions of Environmental Issues for Class 6 Exam

Greenhouse gases and their effects:

Greenhouse gases are the gases that trap heat in the Earth's atmosphere and contribute to global warming. These gases allow sunlight to enter the atmosphere but prevent the heat from escaping back into space. The main greenhouse gases are:

1. Carbon dioxide (CO2)
2. Methane (CH4)
3. Nitrous oxide (N2O)
4. Fluorinated gases (hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride)

Carbon dioxide as a greenhouse gas:

Carbon dioxide (CO2) is a greenhouse gas because it absorbs and emits infrared radiation. It is the most important greenhouse gas produced by human activities, such as burning fossil fuels like coal, oil, and natural gas. Carbon dioxide is also produced by deforestation and other land-use changes.

Effects of carbon dioxide on climate change:

The concentration of carbon dioxide in the atmosphere has increased by about 47% since the Industrial Revolution. This increase in carbon dioxide is causing global temperatures to rise, leading to climate change. The effects of climate change include:

1. Rising sea levels
2. More frequent and severe heatwaves
3. More frequent and severe storms
4. Changes in precipitation patterns
5. Changes in agricultural productivity
6. Increased risk of wildfires

Conclusion:

In conclusion, carbon dioxide is a greenhouse gas that is produced by human activities and is causing global warming and climate change. It is important to reduce carbon dioxide emissions by using renewable energy sources and adopting sustainable practices to mitigate the effects of climate change.

The correct answer is option (d) which is Nitrogen.

Let me explain how.

So

Greenhouse gases (also known as GHGs) are gases in the earth's atmosphere that trap heat. During the day, the sun shines through the atmosphere, warming the earth's surface. At night the earth's surface cools, releasing heat back into the air. But some of the heat is trapped by the greenhouse gases in the atmosphere.



Earth's greenhouse gases trap heat in the atmosphere and warm the planet. The main gases responsible for the greenhouse effect include carbon dioxide, methane, nitrous oxide, and water vapor. In addition to these natural compounds, synthetic fluorinated gases also function as greenhouse gases.



What is the biggest greenhouse gas?

Carbon Dioxide Emissions

Carbon Dioxide Emissions. Carbon dioxide (CO2) is the primary greenhouse gas emitted through human activities. In 2021, CO2 accounted for 79% of all U.S. greenhouse gas emissions from human activities


Is greenhouse gases bad?

This change in concentrations causes warming and is affecting various aspects of climate, including surface air and ocean temperatures, precipitation, and sea levels. Human health, agriculture, water resources, forests, wildlife, and coastal areas are all vulnerable to climate change.


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.




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 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 radiation 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.




Frequently Asked Questions
Q1
What is global warming?
The gradual increase in temperature due to the greenhouse effect caused by pollutants, CFCs and carbon dioxide is called global warming. This phenomenon has disturbed the climatic pattern of the earth.

Q2
List gases which are responsible for the greenhouse effect.
The major greenhouse gases are:
1) Carbon dioxide
2) Methane
3) Water
4) Nitrous oxide
5) Ozone
6) Chlorofluorocarbons (CFCs)

Q3
What is the greenhouse effect?
Carbon dioxide and water vapour absorb infrared radiations coming to the earth and partly reflect it back to the earth’s surface. Due to this, the surface of the earth gets heated up. This phenomenon is called the greenhouse effect.
Q4
What are the major causes of the greenhouse effect?
Burning of fossil fuels, deforestation, farming and livestock production all contribute to the greenhouse effect. Industries and factories also play a major role in the release of greenhouse gases.

Q5
What would have happened if the greenhouse gases were totally missing in the earth’s atmosphere?
Earth’s most abundant greenhouse gases are carbon dioxide, methane, ozone, CFCs, and water vapour. These gases are present near the Earth’s surface. They absorb solar energy that is radiated back from the surface of the Earth. The absorption of radiation results in the heating up of the atmosphere. Hence, greenhouse gases are essential for maintaining the temperature of Earth for the sustenance of life.
In the absence of greenhouse gases, the average temperature of Earth will decrease drastically, making it uninhabitable. As a result, life on Earth would be impossible.



Hence proved that the answer of the given question is option (d) which is Nitrogen.

Conserving Water

Water is a precious resource that is essential for life. However, with increasing population and urbanization, the demand for water is also increasing. Therefore, it is crucial to conserve water to ensure its availability for future generations.

Best Way to Conserve Water

The best way to conserve water is to use it judiciously and avoid wastage. One of the best ways to conserve water is to take a shower with less water. This can be achieved by following the below steps:

1. Install low-flow showerheads: Low-flow showerheads can reduce water consumption by up to 50%. These showerheads use less water without compromising on the pressure or quality of the shower.

2. Time your shower: Timing your shower to last five minutes or less can save a significant amount of water. It is also essential to turn off the shower while lathering your body or shampooing your hair.

3. Use a bucket: Using a bucket while showering can help to collect the water that would otherwise go down the drain. This water can be used to water plants or flush the toilet.

4. Fix leaks: Leaks in the shower or faucet can waste a lot of water. Therefore, it is essential to fix any leaks as soon as possible.

Conclusion

Conserving water is the need of the hour. Taking a shower with less water is one of the best ways to conserve water. By following the above steps, we can reduce our water consumption and make our planet a better place to live.

Introduction:
Acid rain is a type of rain that has high levels of acidity. It is caused by emissions of sulfur dioxide and nitrogen oxide, which react with the atmosphere to form sulfuric acid and nitric acid. Acid rain can have harmful effects on the environment, including plants, animals, buildings, and statues.

Statement (i): Acid rain is harmful to some plants and animals.
This statement is true. Acid rain can have detrimental effects on plants and animals. It damages plant tissues, inhibits photosynthesis, and affects nutrient absorption. It can also disrupt aquatic ecosystems, leading to the decline of certain species of fish and other aquatic organisms.

Statement (ii): Acid rain mainly comprises of sulfuric acid and nitric acid.
This statement is true. Acid rain is primarily composed of sulfuric acid and nitric acid. These acids are formed when sulfur dioxide and nitrogen oxide emissions from burning fossil fuels react with water, oxygen, and other chemicals in the atmosphere.

Statement (iii): Acid rain helps farmers to produce more crops.
This statement is false. Acid rain has negative effects on agriculture. It damages crops, decreases soil fertility, and hinders nutrient uptake by plants. Acidic soils can also release toxic metals, which further harm plant growth. Therefore, acid rain does not help farmers produce more crops; instead, it can decrease crop yields.

Statement (iv): Acid rain corrodes buildings and statues.
This statement is true. Acid rain can corrode buildings and statues made of materials such as limestone, marble, and metals. The sulfuric acid and nitric acid in acid rain react with the materials, causing them to deteriorate over time. This corrosion can lead to the loss of historical and cultural heritage.

Conclusion:
In conclusion, the true statements about acid rain are that it is harmful to some plants and animals, mainly comprises sulfuric acid and nitric acid, and corrodes buildings and statues. Acid rain does not help farmers produce more crops; instead, it has detrimental effects on agriculture.

Global warming is the main reason for the melting of ice-sheets.

Explanation:

Global warming refers to the increase in the Earth's average surface temperature due to the increase in greenhouse gases, such as carbon dioxide, methane, and nitrous oxide, in the atmosphere. These gases trap the heat from the sun and prevent it from escaping into space, causing the Earth's temperature to rise.

The rise in temperature has several consequences, including the melting of ice-sheets. Here's how global warming leads to the melting of ice-sheets:

1. Increase in temperature: As the Earth's temperature rises, the temperature of the air and water around the ice-sheets also increases. This causes the ice to melt and flow into the oceans.

2. Rising sea levels: The melted ice from the ice-sheets flows into the oceans, causing sea levels to rise. This can lead to flooding and other coastal hazards.

3. Feedback loop: The melting of ice-sheets can also create a feedback loop, where the exposed dark surface of the ocean absorbs more heat from the sun, causing further warming and melting of the ice-sheets.

4. Climate change: The melting of ice-sheets can also affect the Earth's climate, as it can alter ocean currents and weather patterns.

In conclusion, global warming is the main reason for the melting of ice-sheets, and it has several consequences for the Earth's climate and environment. It is important to take action to reduce greenhouse gas emissions and mitigate the effects of global warming.

World Water Day

World Water Day is celebrated on 22nd March every year. This day is observed to raise awareness about the importance of freshwater, the need for sustainable management of freshwater resources, and to address the water crisis faced by people around the world.

Water conservation

The theme of World Water Day changes every year, and the focus of the day is on water conservation and critical water issues. The goal is to encourage people to take action to reduce water waste, improve water quality, and protect the planet's water resources.

Importance of water conservation

Water is essential to life, and its conservation is crucial for the survival of all living organisms. However, the world's water resources are under threat due to climate change, pollution, and overuse. Water conservation is essential to ensure that there is enough water for future generations and to protect the environment.

Actions for water conservation

There are many ways people can conserve water, including:

- Fixing leaks in pipes and taps
- Using water-efficient appliances and fixtures
- Taking shorter showers and turning off the tap while brushing teeth
- Collecting rainwater for use in the garden
- Planting native and drought-resistant plants
- Using a broom instead of a hose to clean outdoor areas

Conclusion

World Water Day is an important day to raise awareness about the need for water conservation and critical water issues. It is a reminder that we all have a role to play in protecting our planet's water resources and ensuring that there is enough water for future generations.

Non-renewable natural resources:
Non-renewable natural resources are those that cannot be replenished or replaced within a short period of time. They are formed over millions of years and their availability is limited. Once these resources are depleted, they cannot be easily replenished. Examples of non-renewable resources include fossil fuels like coal, oil, and natural gas, as well as minerals like iron, copper, and aluminum.

Explanation:
The correct answer is option 'B' - non-renewable. This means that most of the natural resources we consume at our homes or in our cars are non-renewable. Here's an explanation of why this is the case:

1. Fossil fuels:
Fossil fuels, such as coal, oil, and natural gas, are widely used for heating, electricity generation, and transportation. These resources were formed from the remains of plants and animals that lived millions of years ago. Fossil fuels are finite resources that are being consumed at a faster rate than they are being formed. Once these resources are depleted, they cannot be easily replaced.

2. Minerals:
Many minerals are also non-renewable resources. These include metals like iron, copper, and aluminum, which are used in the construction of buildings, vehicles, and appliances. These minerals are extracted from the earth's crust through mining processes. However, mining can be destructive to the environment and the extraction of minerals is not sustainable in the long run.

3. Renewable resources:
While there are some renewable resources, such as solar and wind energy, that can be used to power our homes or cars, they are not as widely used as non-renewable resources. Renewable resources can be replenished naturally over a relatively short period of time, making them more sustainable. However, their availability and efficiency still have limitations, which is why they are not the primary sources of energy for most households and vehicles.

In conclusion, the majority of the natural resources we consume at our homes or in our cars are non-renewable. These resources are limited in supply and their extraction and consumption have negative impacts on the environment. It is important to conserve these resources and explore alternative, sustainable options for energy and materials.