ENVIRONMENT GEOGRAPHY TERMS-5

PRERNA FOR IAS

         Mehnat Aapki, Guidance Humari

         Roz ki Prelims Practice — Experts ke Saath

ENVIRONMENT GEOGRAPHY TERMS-5

1. El Niño

El Niño is a climate phenomenon characterized by the unusual warming of sea surface temperatures in the central and eastern tropical Pacific Ocean. It occurs every 2–7 years and is part of the El Niño–Southern Oscillation (ENSO). El Niño weakens the trade winds and alters global weather patterns. In India, it often causes weaker monsoon rainfall, droughts, and reduced agricultural production. Other regions may experience floods, storms, or heatwaves. Scientists monitor El Niño to improve weather forecasting and disaster preparedness. Understanding El Niño is essential for agriculture, water management, and climate studies worldwide.

2. La Niña

La Niña is the opposite phase of El Niño and is characterized by unusually cool sea surface temperatures in the central and eastern Pacific Ocean. During La Niña, trade winds become stronger than normal, increasing the upwelling of cold water. In India, La Niña generally strengthens the southwest monsoon and often brings above-average rainfall. Globally, it influences temperature, rainfall, hurricanes, floods, and drought patterns. La Niña is also a part of the ENSO cycle. Monitoring La Niña helps governments prepare for weather-related disasters and supports agriculture, fisheries, and water resource planning.

3. ENSO

ENSO (El Niño–Southern Oscillation) is a recurring climate system involving changes in sea surface temperatures and atmospheric pressure across the tropical Pacific Ocean. It has three phases: El Niño (warm phase), La Niña (cool phase), and Neutral. ENSO strongly influences global weather, including rainfall, droughts, floods, cyclones, and temperature patterns. In India, ENSO significantly affects the southwest monsoon, agriculture, and water availability. Scientists monitor ENSO using satellite observations and ocean buoys. Understanding ENSO improves climate prediction, disaster management, food security, and long-term environmental planning across the world.

4. Monsoon

A monsoon is a seasonal reversal of winds caused mainly by differential heating of land and sea. During summer, land heats faster than the ocean, creating low pressure over land that draws in moisture-laden winds from the sea, bringing heavy rainfall. In winter, the process reverses, and dry winds blow from land to sea. India experiences the Southwest Monsoon and Northeast Monsoon. Monsoons are vital for agriculture, drinking water, hydroelectric power, and ecosystems. Variations in monsoon intensity influence crop production, water resources, and the national economy.

5. Cyclone

A cyclone is a rapidly rotating low-pressure weather system with strong winds and heavy rainfall. Tropical cyclones develop over warm ocean waters where sea surface temperatures exceed about 26.5°C. Warm, moist air rises, creating low pressure that draws in more air, producing a spiraling storm. Cyclones can cause flooding, storm surges, coastal erosion, and widespread destruction. In the Indian Ocean, they are called cyclones, while similar storms are called hurricanes or typhoons elsewhere. Early warning systems, evacuation plans, and resilient infrastructure help reduce cyclone-related damage and protect human lives.

6. Anticyclone

An anticyclone is a high-pressure weather system where air sinks and spreads outward from the centre. Descending air suppresses cloud formation, resulting in clear skies, dry weather, and light winds. In the Northern Hemisphere, anticyclones rotate clockwise, while in the Southern Hemisphere, they rotate anticlockwise due to the Coriolis Force. Anticyclones are associated with stable atmospheric conditions and pleasant weather but may also cause fog and cold waves during winter. Meteorologists study anticyclones to understand weather forecasting, atmospheric circulation, and seasonal climate variations.

7. Biodiversity Hotspot

A biodiversity hotspot is a region with exceptionally high levels of endemic species that is also under severe threat from habitat loss. The concept was introduced by Norman Myers in 1988. To qualify as a hotspot, an area must contain at least 1,500 endemic plant species and have lost at least 70% of its original habitat. The world has 36 biodiversity hotspots, four of which occur partly or wholly in India: the Western Ghats–Sri Lanka, Himalaya, Indo-Burma, and Sundaland (Nicobar Islands). Protecting hotspots is essential for global biodiversity conservation.

8. Endangered Species

An endangered species is a species facing a very high risk of extinction in the near future due to habitat destruction, poaching, pollution, climate change, invasive species, and overexploitation. The International Union for Conservation of Nature (IUCN) classifies species based on their extinction risk. Examples of endangered species in India include the Bengal Tiger, Asian Elephant, Ganges River Dolphin, and Great Indian Bustard. Conservation measures include protected areas, wildlife laws, habitat restoration, captive breeding, and anti-poaching programmes. Protecting endangered species helps preserve biodiversity and maintain ecological balance.

9. Critically Endangered Species

A critically endangered species faces an extremely high and immediate risk of extinction in the wild. It is the highest threat category before a species becomes extinct in the wild. Causes include habitat destruction, illegal hunting, pollution, climate change, and very small populations. Examples from India include the Great Indian Bustard, Jerdon's Courser, White-rumped Vulture, and Gharial. Intensive conservation measures such as habitat protection, captive breeding, strict legal enforcement, and scientific monitoring are essential for preventing extinction. Conserving critically endangered species preserves genetic diversity and ecological stability.

10. Vulnerable Species

A vulnerable species is one that faces a high risk of becoming endangered if current threats continue. These species have declining populations or shrinking habitats but are not yet at the highest risk of extinction. Major threats include habitat loss, overexploitation, pollution, invasive species, and climate change. Examples include the Snow Leopard, Olive Ridley Turtle, and Indian Rhinoceros (status may vary with updated assessments). Conservation strategies involve habitat restoration, protected areas, community participation, and sustainable resource management. Early conservation action helps prevent vulnerable species from becoming endangered.

11. Extinct Species

An extinct species is a species for which no living individual remains anywhere on Earth. Extinction occurs due to natural events or human activities such as habitat destruction, hunting, pollution, invasive species, and climate change. Once a species becomes extinct, it cannot naturally return. Famous examples include the Dodo, Passenger Pigeon, and Tasmanian Tiger. Extinction reduces biodiversity, weakens ecosystems, and disrupts ecological balance. Preventing extinction requires conservation of habitats, sustainable resource use, wildlife protection laws, and public awareness. Conserving existing species is essential for maintaining Earth's biological diversity.

12. IUCN Red List

The IUCN Red List of Threatened Species is the world's most comprehensive inventory of the global conservation status of plants, animals, and fungi. Prepared by the International Union for Conservation of Nature (IUCN), it classifies species into categories such as Least Concern, Near Threatened, Vulnerable, Endangered, Critically Endangered, Extinct in the Wild, and Extinct. Scientists use the Red List to identify threatened species, guide conservation planning, and monitor biodiversity trends. Governments and environmental organizations rely on the Red List to develop effective wildlife protection policies and conservation strategies.

13. Ramsar Convention

The Ramsar Convention is an international treaty adopted in 1971 at Ramsar, Iran, for the conservation and wise use of wetlands. It promotes sustainable management of wetlands because of their ecological, economic, cultural, and scientific importance. Countries that join the convention designate important wetlands as Ramsar Sites. India has numerous Ramsar Sites, including Chilika Lake, Keoladeo National Park, and Sundarbans Wetland. The convention encourages wetland restoration, biodiversity conservation, and international cooperation. Protecting wetlands supports flood control, water purification, groundwater recharge, fisheries, and habitat for migratory birds.

14. Montreal Protocol

The Montreal Protocol is an international environmental agreement signed in 1987 to protect the ozone layer by gradually eliminating ozone-depleting substances such as chlorofluorocarbons (CFCs), halons, and carbon tetrachloride. It is regarded as one of the most successful global environmental treaties because nearly every country participates. The protocol has significantly reduced emissions of harmful chemicals, allowing the ozone layer to recover gradually. It also con