Previous Year Question
Which of the following are the impacts of Global Warming?
Rise in sea level
Melting of glaciers
Spread of diseases
Bleaching of Coral reefs
Select the correct answer using the codes given below:
1, 2 and 3 only
2 and 3 only
1, 3 and 4 only
1, 2, 3 and 4
Correct Answer: D
Detailed Solution
Global Warming refers to the long-term increase in the Earth's average surface temperature. Its principal cause is the rising concentration of Greenhouse Gases, including Carbon Dioxide (CO₂) and Methane (CH₄), due to human activities. Statement 1 is correct. Increasing temperatures cause Thermal Expansion of seawater, while the melting of land-based glaciers and ice sheets adds additional water to the oceans. Both processes contribute to Sea Level Rise, increasing the risks of coastal flooding, coastal erosion, and saltwater intrusion.
Statement 2 is correct. Global Warming accelerates the melting and shrinking of Glaciers. Rising temperatures in the Himalayas, Alps, and other mountainous regions affect the Mass Balance of glaciers. Glacier retreat can initially increase river discharge and the expansion of glacial lakes, while potentially reducing the long-term availability of glacier-dependent water resources. According to the IPCC, human influence has been the principal driver of global glacier retreat since the 1990s.
Statement 3 is correct. Global Warming and Climate Change can increase the risk of spreading Infectious Diseases. Changes in temperature, rainfall, and humidity influence the reproduction, activity, and geographical distribution of disease-carrying Vectors, such as mosquitoes. This can increase the likelihood of diseases such as Malaria, Dengue, and Chikungunya spreading in certain regions. Additionally, floods, droughts, and contaminated water may increase the risk of Water-borne Diseases such as Cholera and Diarrhoea. However, actual disease transmission also depends on local climate, sanitation, and healthcare services.
Statement 4 is correct. Coral Bleaching is a major environmental problem associated with abnormal increases in ocean temperatures. Corals contain symbiotic photosynthetic algae called Zooxanthellae, which provide them with nutrients and colour. When seawater temperatures rise excessively, corals may become stressed and expel these algae, causing them to appear white. Prolonged Thermal Stress can lead to coral mortality. However, some bleached corals can recover if favourable environmental conditions return.