Maharashtra Board Class 11 Geography Important Questions Chapter 5 Global Climate Change

Balbharti Maharashtra State Board Class 11 Geography Important Questions Chapter 5 Global Climate Change Important Questions and Answers.

Maharashtra State Board 11th Geography Important Questions Chapter 5 Global Climate Change

Complete the chain

Question 1.

A	B	C
(1) Different density of corals in summer and winter	(1) Ice cores	(1) Understanding of past environmental conditions
(2) Variation in environmental conditions	(2) Goldilocks Zone	(2) Summer snow different from winter snow
(3) Samples of ice from inner sides of the ice sheets	(3) Creates seasonal growth rings on corals	(3) Earth was cooler when it was located in the outer reaches of this zone
(4) Habitable zone in which the Earth lies	(4) Tree rings	(4) Determines the temperature of water and season in which coral grew

Answer:

A	B	C
(1) Different density of corals in summer and winter	(1) Creates seasonal growth rings on corals	(1) Determines the temperature of water and season in which coral grew
(2) Variation in environmental conditions	(2) Tree rings	(2) Understanding ofpast environmental condition
(3) Samples of ice from inner sides of the ice sheets	(3) Ice cores	(3) Summer snow different from winter snow
(4) Habitable zone in which the Earth lies	(4) Goldilocks Zone	(4) Earth was cooler when it was located in the outer reaches of this zone

Choose the correct option by identifying the correct correlation in the sentences.

Question 1.
Urban areas heat up more readily because …………………..
(a) of presence of deserts
(b) of paved surfaces and concrete constructions
(c) they have many industries
(d) they are in plain regions
Answer:
(b) of paved surfaces and concrete constructions

Question 2.
Global sea level rise is apparently being caused because of …………………….
(a) increased melting of ice such as glaciers and ice sheets
(b) frequent flooding of coastal areas
(c) increase in precipitation
(d) flash floods
Answer:
(a) increased melting of ice such as glaciers and ice sheets

Question 3.
Around the world the jellyfish seem to be reproducing heavily and congregating in places because of ………………
(a) melting of ice sheets
(b) global warming
(c) sea water is rising
(d) warmer waters and changes in the acidity level of the oceans.
Answer:
(d) warmer waters and changes in the acidity level of the oceans.

Question 4.
These has been an increase in number of flash floods and also the duration of floods because of ……………….
(a) increased deforestation
(b) melting of glaciers
(c) very high precipitation in one day
(d) increase of volume of water in rivers
Answer:
(c) very high precipitation in one day

Question 5.
It has been observed that with more CO<sub>2</sub>, in the air, crop yield has …………………
(a) increased
(b) decreased
(c) remained constant
(d) changed
Answer:
(a) increased

Question 6.
The average temperature of earth is around …………………
(a) 10°C
(b) 12°C
(c) 14°C
(d) 16°C
Answer:
(c) 14°C

Question 7.
Receding glaciers as a symptom of global climate change has been observed in the glaciers near ………………. in Africa.
(a) Mt. Kilimanjaro
(b) Mt. Kenya
(c) Mt. Meru
(d) Mt. Toubkal
Answer:
(a) Mt. Kilimanjaro

Question 8.
An increase of 1° – 2°C in ocean temperatures for a long time can lead to …………………. of corals.
(a) growth
(b) bleaching
(c) death
(d) congregation
Answer:
(b) bleaching

Question 9.
The roots of both flooding and drought lie in the physical process known as …………………
(a) erosion
(b) transportation
(c) deposition
(d) evaporation
Answer:
(d) evaporation

Question 10.
The ………………… in the trees provide clues about wet and dry periods.
(a) branches
(b) wood
(c) rings
(d) leaves
Answer:
(c) rings

Identify the correct correlation.

A : Assertion
R : Reasoning

Question 1.
A – India has high vulnerabilities to climate change.
R – India has peculiar economy and geography.
(a) Only A is correct.
(b) Only R is correct.
(c) Both A and R are correct and R is the correct explanation of A.
(d) Both A and R are correct but R is not the correct explanation of A.
Answer:
(d) Both A and R are correct but R is not the correct explanation of A.

Question 2.
A – More than one-fifth of the coral reefs are already lost.
R – Coral bleaching leads to death of large amount of corals.
(a) Only A is correct.
(b) Only R is correct.
(c) Both A and R are correct and R is the correct explanation of A.
(d) Both A and R are correct but R is not the correct explanation of A.
Answer:
(d) Both A and R are correct but R is not the correct explanation of A.

Question 3.
A – Coral formed in the summer has a different density than coral formed in the winter.
R – Summer snow differs from winters snow.
(a) Only A is correct.
(b) Only R is correct.
(c) Both A and R are correct and R is the correct explanation of A.
(d) Both A and R are correct but R is not the correct explanation of A.
Answer:
(d) Both A and R are correct but R is not the correct explanation of A.

Question 4.
A – Volcanism is considered as a cause of climate change.
R – The winds spread aerosols around the world reducing sun’s radiation to reach on earth’s surface.
(a) Only A is correct.
(b) Only R is correct.
(c) Both A and R are correct and R is the correct explanation of A.
(d) Both A and R are correct but R is not the correct explanation of A.
Answer:
(d) Both A and R are correct but R is not the correct explanation of A.

Question 5.
A – Higher sea levels may lead to deadlier cyclones and also frequent flooding of coastal areas.
R – High precipitation leads to higher sea level.
(a) Only A is correct.
(b) Only R is correct.
(c) Both A and R are correct and R is the correct explanation of A.
(d) Both A and R are correct but R is not the correct explanation of A.
Answer:
(a) Only A is correct.

Identify the incorrect factor.

Question 1.
Causes of climate change-
(a) Melting of glaciers
(b) Amount of energy
(c) Milankovitch oscillations
(d) Volcanism
Answer:
(a) Melting of glaciers

Question 2.
Some indirect effects of warming up of earth-
(a) Spread of insects in newer region
(b) Sea level rise
(c) Bleaching of corals
(d) Heavy reproduction of jellyfish
Answer:
(b) Sea level rise

Question 3.
Effects of global warming are-
(a) Heat wave
(b) Increase in sea level
(c) Heat islands
(d) Deforestation
Answer:
(d) Deforestation

Give geographical reasons.

Question 1.
Man and his activities are the major cause of climate change.
Answer:
Man and his activities are major cause of climate change because-

Besides natural causes there is an anthropogenic effect on the climate.
Due to human activities many greenhouse gases mainly Carbon Dioxide (CO₂) is released in the atmosphere.
The emission of CO₂ mainly comes from fossil fuel combustion.
Large scale deforestation also increases CO₂.
The atmosphere takes around 20 to 25 years to adjust these high levels of CO₂.

Question 2.
The change in climate is a natural and continuous process.
Answer:

The change in climate is a natural and continuous process because-
The earth has witnessed many variations in climate since the beginning.
There are various geological records that show alteration of glacial and inter-glacial periods.
The sediment deposits in glacial lakes also reveal the occurrence of warm and cold periods.
The rings in the trees provide clues about wet and dry periods.
Historical records describe the variations in climate.
All these evidences indicate that change in climate is a natural and continuous process.

Question 3.
Rainforest play a major role in cooling the earth.
Answer:
Rainforest play a major role in cooling the earth because-

Dense forest has a direct effect on the temperature of that area.
In moist tropical region there is dense forest growth, they form canopy. The broad leaves of the forest help to trap moisture and allow it to evaporate, so there is natural cooling effect.
When these forests are slashed and burnt over large area, hot and dry air spreads and the temperature of the area increases.
When forests are burnt, large amount of carbon dioxide is added to the atmosphere and there is air pollution, which also leads to global warming.
Heavy deforestation leads to decrease in the rainfall of that area and changes in rainfall pattern are observed.

Write short notes on.

Question 1.
Greenhouse gases
Answer:

Greenhouse gases are the primary gases, such as, water vapour carbon dioxide, nitrous oxide, methane and ozone in the earth’s atmosphere that absorbs and traps energy from the sun.
Of all greenhouse gases, carbon dioxide absorbs more heat.
Without greenhouse gases, the average temperature of the earth’s surface would be about -18°C rather than the present average of 14°C.
Carbon dioxide emissions comes from many human activities such as combustion of fossil fuels, oil and natural gas, with additional contributions coming from deforestation, changes in land use, soil erosion and agriculture (including live stock).

Question 2.
Causes of climate change
Answer:
Though human activities are a major cause for climate change, some natural causes are responsible for climate change. Following are some of the natural causes of climate change:
The amount of energy output by the sun is not the same always. Low energy output by sun can reduce amount of insolation received by the earth. This can lead to cooling of earth.

Another cause is the Milankovitch oscillation. Variations in the earth’s orbital characteristics around the sun and the changes in the earth’s axial tilt occur. These factors cause the earth to be closer to the sun (warmer) or farther from the sun (colder). Ice ages can occur when we are farther from the sun.

Volcanism is considered as another cause for climate change. Volcanic eruptions throw lots of particulates, and aerosols into the atmosphere. The winds spread it around the world reducing the sun’s radiation reaching the earth’s surface.

The habitable zone of the earth is called Goldilocks Zone. It means as the size of the sun increases, the zone moves outwards overtime. Such changes in zone causes earth to warm or cool.

Besides natural causes, anthropogenic activities affect the climate. The emission of CO₂ from fossil fuel combustion. Large-scale deforesting also increases CO₂. It takes around 20 to 25 years to adjust these high levels of CO₂.

Answer in detail.

Question 1.
Explain the effects global warming.
Answer:
The average temperature of the Earth is around 14°C. As given in the earlier graph, this average temperature has increased by 0.8° C. However, the following are the effects of global warming.

Heat waves:

Increase in the heat holding capacity of the atmosphere increases the temperature especially during summers.
Summers can become more intense or even deadlier and could bring hot spells.

Heat islands:

Global warming serves as a base from which heat waves become much worse – especially in big cities where the heat island effect comes into play.
Urban areas heat up more readily because of paved surface and concrete constructions as compared to a field or forest areas.

Increase in sea level:

Due to increased melting of ice such as glaciers and ice sheets, there is a global rise in the sea level every year.
Higher sea levels may lead to deadlier cyclones and also frequent flooding of coastal areas.
Many islands are also at risk of getting submerged.
It may result in saline coastal groundwater endangered wetlands and flooding of cities and coastal communities. For example, Mumbai and parts of Konkan coastline.
It also means loss of habitat for fish, birds and plants.
As per the studies carried out by the Indian National Centre for Ocean Information Services, sea level may rise 9 to 90 cm between 1900 and 2100.

Melting of glaciers at high altitudes and snow in polar areas:

Melting of glaciers is a natural process, but when glaciers and iceberg melt at an alarming rate, it is a cause of concern.
Retreating of glaciers is considered as a symptom of global climate change. This means there is lesser ice formation each year than of melting.
Over the last 25 years, Gangotri glacier has retreated more than 850 meters, with a recession of 76 meters from 1996 to 1999.

Other factors:

Around the world the jellyfish seem to be reproducing heavily and congregating in places where they were never seen before.
This happens because of warmer waters and changes in the acidity level of the oceans.
Spread of insects in newer region apparently increases the number of mosquitoes.
Bleaching of the corals take place due to increase in the ocean temperatures. Coral bleaching leads to death of large numbers of corals.

Question 2.
Explain the various tools for studying climate change.
Answer:
Scientists and meteorologists have been using instruments to measure climate and weather for the past 140 years. However, millions of years ago historical evidence called proxy data, which includes coral reefs, tree rings, ice cores, etc., were used to tell about the climate.
Coral reefs:

Coral reefs are very sensitive to changes in climate.
Corals form skeletons by extracting calcium carbonate from the ocean waters.
When the temperature changes, densities of calcium carbonate in the skeletons also change.
Coral formed in the summer has a different density than coral formed in the winter.
This creates seasonal growth rings on the corals.
Scientists can study these rings to determine the temperature of the water and the season in which the coral grew.

Tree rings:

Variation in these rings is due to variation in the environmental conditions when they were formed.
Thus, studying this variation leads to improved understanding of past environmental conditions.

Ice cores:

These are samples of ice taken from the inner sides of the ice sheets.
Throughput each year, layers of snow fall over the ice sheets in Greenland and Antarctica.
Each layer of snow is different.
Summer snow differs from winter snow.
Each layer gives scientists a lot of information about the climate each year.