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Earth—Our Shared Home - Forest and Climate Change

Grade 5CBSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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Forests as the 'Lungs of the Earth': Forests play a crucial role in maintaining the balance of gases by absorbing Carbon Dioxide (CO2CO_2) and releasing Oxygen (O2O_2) through the process of photosynthesis.

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The Greenhouse Effect: It is a natural process where certain gases like CO2CO_2, methane (CH4CH_4), and water vapor trap heat in the atmosphere to keep the Earth warm. However, excess greenhouse gases lead to Global Warming.

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Global Warming: The gradual increase in the Earth's average surface temperature due to human activities like deforestation and burning of fossil fuels.

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Deforestation and its Impact: Clearing forests leads to soil erosion, loss of habitat for wildlife, and an increase in CO2CO_2 levels, which contributes to climate change.

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Photosynthesis Equation: Plants take in carbon dioxide and water to produce glucose and oxygen in the presence of sunlight: 6CO2+6H2O→SunlightC6H12O6+6O26CO_2 + 6H_2O \xrightarrow{Sunlight} C_6H_{12}O_6 + 6O_2.

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Afforestation vs. Reforestation: Afforestation is planting trees in an area where there was no previous tree cover, while Reforestation is replanting trees in a forest that has been depleted.

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Conservation Movements: Important movements like the 'Chipko Movement' highlight the role of local communities in protecting forests by hugging trees to prevent them from being cut down.

📐Formulae

6CO2+6H2O→sunlight/chlorophyllC6H12O6+6O26CO_2 + 6H_2O \xrightarrow{\text{sunlight/chlorophyll}} C_6H_{12}O_6 + 6O_2

Ideal Forest Cover=33% of total land area\text{Ideal Forest Cover} = 33\% \text{ of total land area}

ΔT=Tfinal−Tinitial\Delta T = T_{final} - T_{initial}

💡Examples

Problem 1:

A region had a total forest cover of 8,500 sq km8,500 \text{ sq km}. After a decade of heavy logging and urban development, the forest area was reduced by 2,750 sq km2,750 \text{ sq km}. Calculate the remaining forest area.

Solution:

Remaining Area = 8,500−2,750=5,750 sq km8,500 - 2,750 = 5,750 \text{ sq km}

Explanation:

To find the remaining forest cover, we subtract the area lost from the original area using vertical subtraction: 8500−27505750\begin{array}{r} 8500 \\ - 2750 \\ \hline 5750 \end{array}

Problem 2:

If the average global temperature increases by 0.02∘C0.02^\circ C every year due to the greenhouse effect, how much will the temperature increase over a period of 5050 years?

Solution:

0.02×50=1.0∘C0.02 \times 50 = 1.0^\circ C

Explanation:

The total increase in temperature is calculated by multiplying the annual rate of increase (0.020.02) by the number of years (5050). This shows that even small annual changes can lead to a significant rise of 1∘C1^\circ C over half a century.

Problem 3:

If a single mature tree can absorb approximately 22 kg22 \text{ kg} of CO2CO_2 per year, how much CO2CO_2 will a small grove of 150150 trees absorb in one year?

Solution:

150×22=3300 kg150 \times 22 = 3300 \text{ kg}

Explanation:

By multiplying the number of trees by the absorption rate per tree, we find the total carbon sequestration. 150×22300+30003300\begin{array}{r} 150 \\ \times 22 \\ \hline 300 \\ + 3000 \\ \hline 3300 \end{array} The grove absorbs 3,300 kg3,300 \text{ kg} of CO2CO_2 annually.