World Climate and Climate Change

Climate vs. Weather

• Weather: Short-term atmospheric conditions (hours/days) in a specific area.
  • Example: A sudden thunderstorm in Delhi on a summer afternoon.
• Climate: Long-term pattern of weather (over 30+ years) in a region.
  • Example: The average monsoon rainfall pattern in India over decades.
• Elements of Weather and Climate: Temperature, precipitation, humidity, pressure, wind, etc.

Classification of Climate

Koeppen’s Climate Classification

• Most widely used classification system based on temperature and precipitation.
• Five major climate groups (A, B, C, D, E) with subcategories:
  1. A – Tropical Climates:
     • Characteristics: High temperatures throughout the year, abundant rainfall.
     • Subtypes:
       • Af: Tropical rainforest:
         • Example: Amazon Basin, Congo Basin.
         • Features: High rainfall year-round, dense forests.
       • Am: Tropical monsoon:
         • Example: Western Ghats, Southeast Asia.
         • Features: Heavy rainfall in summer, dry winter.
       • Aw: Tropical savanna:
         • Example: Central India, African savannas.
         • Features: Distinct wet and dry seasons, grasslands.
  2. B – Dry Climates:
     • Characteristics: Low precipitation, high evaporation.
     • Subtypes:
       • BWh: Hot desert:
         • Example: Sahara Desert, Arabian Desert.
         • Features: Extremely hot, minimal rainfall.
       • BWk: Cold desert:
         • Example: Gobi Desert, Patagonian Desert.
         • Features: Cold winters, low rainfall.
       • BSh: Hot semi-arid:
         • Example: Rajasthan (India), parts of Australia.
         • Features: Moderate rainfall, hot temperatures.
       • BSk: Cold semi-arid:
         • Example: Parts of Central Asia.
         • Features: Cooler temperatures, moderate rainfall.
  3. C – Temperate Climates:
     • Characteristics: Mild winters and warm summers.
     • Subtypes:
       • Cfa: Humid subtropical:
         • Example: Eastern USA, Eastern China.
         • Features: Hot summers, mild winters, high humidity.
       • Cfb: Marine west coast:
         • Example: Western Europe, New Zealand.
         • Features: Mild temperatures year-round, high rainfall.
       • Csa: Mediterranean:
         • Example: Southern Europe, California.
         • Features: Hot, dry summers and mild, wet winters.
  4. D – Continental Climates:
     • Characteristics: Severe winters and warm summers.
     • Subtypes:
       • Df: Humid continental:
         • Example: Siberia, Northeastern USA.
         • Features: Large temperature variations, moderate rainfall.
       • Dw: Dry winter continental:
         • Example: Northeast China, North Korea.
         • Features: Cold, dry winters and warm, wet summers.
  5. E – Polar Climates:
     • Characteristics: Extremely cold temperatures.
     • Subtypes:
       • ET: Tundra:
         • Example: Arctic regions (Alaska, Northern Canada).
         • Features: Short summers, permafrost, low vegetation.
       • EF: Ice cap:
         • Example: Antarctica, Greenland.
         • Features: Permanent ice cover, extremely cold.

Factors Influencing Climate

1. Latitude:
   • Explanation: Latitude determines the angle at which the sun’s rays strike the Earth, affecting the amount of solar energy received.
   • Example:
     • Equatorial regions (0° latitude) receive direct sunlight year-round, making them warm (e.g., Amazon Rainforest).
     • Polar regions (90° latitude) receive slanting rays, making them cold (e.g., Antarctica).
2. Altitude:
   • Explanation: As altitude increases, temperature decreases due to the thinning of the atmosphere.
   • Example:
     • Mount Kilimanjaro (Tanzania) has snow at its peak despite being near the equator.
     • The Andes Mountains have cooler temperatures at higher elevations compared to the surrounding lowlands.
3. Pressure and Wind Systems:
   • Explanation: Atmospheric pressure and wind patterns influence temperature and precipitation. High-pressure areas are dry, while low-pressure areas are associated with rainfall.
   • Example:
     • The Indian Monsoon is driven by low-pressure systems over the Indian subcontinent.
     • The Sahara Desert experiences high pressure, leading to dry conditions.
4. Distance from the Sea:
   • Explanation: Coastal areas have moderate climates due to the influence of sea breezes, while inland areas experience extreme temperatures.
   • Example:
     • Mumbai (coastal) has a moderate climate, while Delhi (inland) experiences extreme summers and winters.
5. Ocean Currents:
   • Explanation: Warm currents raise temperatures, while cold currents lower them.
   • Example:
     • The Gulf Stream warms Western Europe, making it milder than other regions at similar latitudes.
     • The cold Humboldt Current cools the western coast of South America.
6. Relief Features:
   • Explanation: Mountains can block or redirect wind and precipitation, creating rain shadows.
   • Example:
     • The Western Ghats block monsoon winds, causing heavy rainfall on the windward side and a rain shadow on the leeward side (e.g., Deccan Plateau).

Climate Change

• Definition: Long-term changes in temperature, precipitation, and other atmospheric conditions.
• Causes:
  • Natural Causes:
    • Volcanic eruptions, solar radiation variations, and Earth’s orbital changes.
  • Anthropogenic Causes:
    • Greenhouse gas emissions (CO2, CH4), deforestation, and industrialization.
• Impacts:
  • Rising sea levels, melting glaciers, extreme weather events, and biodiversity loss.
• Mitigation Measures:
  • Renewable energy, afforestation, and international agreements (e.g., Paris Agreement).

Global Warming

• Definition: Increase in Earth’s average surface temperature due to greenhouse gases.
• Effects:
  • Melting polar ice, rising sea levels, and disruption of ecosystems.
• Example:
  • The Arctic ice cap is shrinking at an alarming rate, threatening species like polar bears.

Role of Human Activities in Climate Change

• Industrialization: Increased CO2 emissions from burning fossil fuels.
• Deforestation: Reduces carbon sinks, increasing atmospheric CO2.
• Agriculture: Methane emissions from livestock and rice paddies.

International Efforts to Combat Climate Change

• Paris Agreement (2015): Aims to limit global warming to well below 2°C above pre-industrial levels.
• Kyoto Protocol (1997): Set binding emission reduction targets for developed countries.

MCQ PRACTICE
Question 1:

Statement 1: Climate refers to short-term atmospheric conditions in a specific area.
Statement 2: Weather refers to the long-term pattern of atmospheric conditions over 30+ years.

Which of the above statements is/are correct?
(a) Only 1
(b) Only 2
(c) Both 1 and 2
(d) Neither 1 nor 2

Answer: (d) Neither 1 nor 2
Explanation: Climate refers to long-term patterns (30+ years), while weather refers to short-term conditions (hours/days). Both statements are incorrect.

Question 2:

Statement 1: The Koeppen climate classification system is based on temperature and precipitation.
Statement 2: The ‘Af’ subtype in Koeppen’s classification represents tropical monsoon climates.

Which of the above statements is/are correct?
(a) Only 1
(b) Only 2
(c) Both 1 and 2
(d) Neither 1 nor 2

Answer: (a) Only 1
Explanation: The Koeppen system is based on temperature and precipitation, but ‘Af’ represents tropical rainforest climates, not tropical monsoon.

Question 3:

Statement 1: The ‘BWh’ subtype in Koeppen’s classification represents hot deserts like the Sahara.
Statement 2: The ‘ET’ subtype represents ice cap climates found in Antarctica.

Which of the above statements is/are correct?
(a) Only 1
(b) Only 2
(c) Both 1 and 2
(d) Neither 1 nor 2

Answer: (a) Only 1
Explanation: ‘BWh’ represents hot deserts like the Sahara, but ‘ET’ represents tundra climates, not ice cap climates (‘EF’ represents ice caps).

Question 4:

Statement 1: Latitude determines the angle at which the sun’s rays strike the Earth, affecting solar energy received.
Statement 2: Altitude has no impact on temperature as the atmosphere remains uniformly dense.

Which of the above statements is/are correct?
(a) Only 1
(b) Only 2
(c) Both 1 and 2
(d) Neither 1 nor 2

Answer: (a) Only 1
Explanation: Latitude affects solar energy, but altitude also impacts temperature—higher altitudes have cooler temperatures due to thinner air.

Question 5:

Statement 1: The Gulf Stream is a warm ocean current that moderates the climate of Western Europe.
Statement 2: The Humboldt Current is a cold ocean current that cools the western coast of South America.

Which of the above statements is/are correct?
(a) Only 1
(b) Only 2
(c) Both 1 and 2
(d) Neither 1 nor 2

Answer: (c) Both 1 and 2
Explanation: Both statements are correct. The Gulf Stream warms Western Europe, and the Humboldt Current cools South America’s western coast.

Question 6:

Statement 1: The Western Ghats block monsoon winds, creating a rain shadow on the Deccan Plateau.
Statement 2: Coastal areas generally experience more extreme temperatures compared to inland areas.

Which of the above statements is/are correct?
(a) Only 1
(b) Only 2
(c) Both 1 and 2
(d) Neither 1 nor 2

Answer: (a) Only 1
Explanation: The Western Ghats create a rain shadow, but coastal areas have moderate climates, while inland areas experience extreme temperatures.

Question 7:

Statement 1: Climate change is solely caused by natural factors like volcanic eruptions and solar radiation variations.
Statement 2: Anthropogenic activities like deforestation and industrialization contribute significantly to climate change.

Which of the above statements is/are correct?
(a) Only 1
(b) Only 2
(c) Both 1 and 2
(d) Neither 1 nor 2

Answer: (b) Only 2
Explanation: Climate change is caused by both natural and human activities, but anthropogenic factors like deforestation and industrialization are significant contributors.

Question 8:

Statement 1: The Paris Agreement aims to limit global warming to well below 2°C above pre-industrial levels.
Statement 2: The Kyoto Protocol set binding emission reduction targets for developing countries only.

Which of the above statements is/are correct?
(a) Only 1
(b) Only 2
(c) Both 1 and 2
(d) Neither 1 nor 2

Answer: (a) Only 1
Explanation: The Paris Agreement aims to limit global warming, but the Kyoto Protocol set targets for developed countries, not just developing ones.

Question 9:

Statement 1: Global warming leads to rising sea levels due to the melting of polar ice caps.
Statement 2: Methane emissions from livestock and rice paddies are significant contributors to global warming.

Which of the above statements is/are correct?
(a) Only 1
(b) Only 2
(c) Both 1 and 2
(d) Neither 1 nor 2

Answer: (c) Both 1 and 2
Explanation: Both statements are correct. Melting ice caps raise sea levels, and methane from livestock and rice paddies is a major greenhouse gas.

Question 10:

Statement 1: The ‘Cfb’ subtype in Koeppen’s classification represents marine west coast climates, like Western Europe.
Statement 2: The ‘Df’ subtype represents humid continental climates, like Siberia.

Which of the above statements is/are correct?
(a) Only 1
(b) Only 2
(c) Both 1 and 2
(d) Neither 1 nor 2

Answer: (c) Both 1 and 2
Explanation: Both statements are correct. ‘Cfb’ is marine west coast (e.g., Western Europe), and ‘Df’ is humid continental (e.g., Siberia).