Previous Year Question
Which of the following are the primary causes of climate change?
Excessive burning of fossil fuels
Exploding numbers of automobiles driven by oil
Increasing solar flares
Heavy deforestation
Select the correct answer using the code given below:
2 and 3 only
1, 2 and 4 only
1, 2, 3 and 4
1 and 4 only
Correct Answer: B
Detailed Solution
Climate Change refers to long-term changes in temperature, precipitation, wind patterns, and other climatic conditions. The principal cause of current Global Warming is the increasing atmospheric concentration of Greenhouse Gases resulting from human activities. Major greenhouse gases include Carbon Dioxide (CO₂), Methane (CH₄), and Nitrous Oxide (N₂O). These gases absorb Infrared Radiation emitted from the Earth's surface and intensify the Greenhouse Effect. According to the IPCC, human activities have been the decisive cause of modern global warming.
Statement 1 — Excessive Burning of Fossil Fuels: Combustion of coal, petroleum, and natural gas releases large quantities of CO₂ into the atmosphere. Thermal Power Plants, industries, and energy production are major sources. Statement 2 — Rapid Increase in Petroleum-powered Automobiles: Burning petrol and diesel in vehicles produces CO₂ emissions. An increase in vehicle numbers, fuel consumption, and transportation activities can raise greenhouse gas emissions from the transport sector.
Statement 3 — Increase in Solar Flares: Solar Flares are intense radiation events resulting from the sudden release of magnetic energy near the Sun's surface. They can affect the Earth's Ionosphere, radio communications, and Space Weather. Although long-term variations in solar radiation can influence natural climate variability, increasing Solar Flares are not a major cause of contemporary global climate change. According to NASA, there has been no sustained upward trend in solar energy reaching the Earth since the 1950s, whereas global temperatures have increased significantly.
Statement 4 — Heavy Deforestation: Forests absorb atmospheric CO₂ through Photosynthesis and store carbon through Carbon Sequestration. Large-scale deforestation reduces the capacity for carbon absorption, while burning or decomposition of trees can release stored carbon back into the atmosphere. Land-use Change also contributes to greenhouse gas emissions. According to the IPCC Sixth Assessment Report, approximately 22% of global anthropogenic greenhouse gas emissions in 2019 were associated with Agriculture, Forestry, and Other Land Use (AFOLU).