The question asks about the threats to coral reefs from sea level rise. We need to identify the primary mechanisms through which rising sea levels impact coral health and survival, considering the options provided.
Correct Option: B) Acidification and salinity
Ocean acidification is a major threat to coral reefs. As the ocean absorbs more carbon dioxide from the atmosphere (a process linked to the same greenhouse gas emissions causing global warming and sea level rise), its pH decreases, making it more acidic. This reduces the availability of carbonate ions, which corals need to build their calcium carbonate skeletons. While sea level rise itself might not directly cause widespread salinity changes that threaten corals (unless it leads to freshwater intrusion in specific areas), ocean acidification is a profound and widespread threat directly associated with the broader climate change phenomenon that also causes sea level rise.
The question asks for a marine ecosystem consequence of climate change. We need to identify which of the given options is a direct and well-documented impact of climate change on marine environments.
C) Coral bleaching is a direct and well-documented consequence of climate change, primarily driven by rising ocean temperatures and ocean acidification. These conditions stress corals, causing them to expel symbiotic algae and lose their color, often leading to their death.
The question asks to identify the region most susceptible to Glacial Lake Outburst Floods (GLOFs). GLOFs are sudden releases of water from glacial lakes, often triggered by glacial melt, landslides, or seismic activity. Therefore, the region must have significant glaciers and glacial lakes.
C) Eastern Himalayas — The Himalayas, including the Eastern Himalayas, are a glaciated region with numerous glacial lakes. Climate change is causing glaciers to retreat and glacial lakes to expand, significantly increasing the risk of Glacial Lake Outburst Floods (GLOFs) in this area.
UPSC - 2014
The question asks about the functions of the Global Environment Facility (GEF). To answer this, one needs to know the primary roles and mandates of GEF as an international financial mechanism.
Correct Option: A) It serves as financial mechanism for ‘Convention on Biological Diversity’ and ‘United Nations Framework Convention on Climate Change’.
The question asks to identify the river system that is NOT directly affected by Himalayan glacier melt. This requires knowledge of the geographical origin and primary water sources of major Indian river systems.
Correct Option: B) Krishna — The Krishna River is a major peninsular river in India, originating in the Western Ghats. Its primary source of water is rainfall during the monsoon season, not the meltwater from Himalayan glaciers.
The question asks to identify an ecosystem that serves as both a carbon sink and a flood barrier. We need to evaluate each option based on these two characteristics.
C) Mangroves — Mangroves are highly effective carbon sinks due to their ability to sequester large amounts of carbon in their biomass and sediments. Their dense root systems and unique coastal location also make them excellent natural flood barriers, protecting coastlines from erosion, storm surges, and tsunamis.