All posts by Neetu Singh

Geography Answer Writing Program, Current Affairs

India’s New Proposed Urban Criteria: Everything You Need to Know

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The New Rules of Urbanization: India’s Proposed City Classification Criteria

India’s traditional framework for classifying urban areas is governed entirely by the Census of India. This system, which has remained largely unchanged since 1961, divides urban areas into two distinct classifications: Statutory Towns and Census Towns.

For a settlement to be officially declared “urban” in India, it must fall into one of these two categories.

Statutory Towns

Statutory towns are urban areas defined strictly by administrative and legal status. Regardless of their actual demographic characteristics, these places are notified by a state law or statute.

  • Definition: Any place that possesses an urban local government body.
  • Governing Bodies: This includes Municipal Corporations, Municipal Councils, Cantonment Boards, or Notified Town Area Committees.
  • Key Characteristic: They have a formal, legally recognized municipal administration to manage civic amenities.

Census Towns

Census towns are settlements that are administratively governed as villages (rural panchayats) but display distinct urban demographic characteristics. To be classified as a Census Town, a settlement must satisfy all three of the following criteria simultaneously:

Criterion Metric / Threshold
1. Minimum Population A population of at least 5,000 inhabitants.
2. Workforce Composition At least 75% of the male main working population must be engaged in non-agricultural pursuits.
3. Population Density A density of population of at least 400 persons per square kilometer (or roughly 1,000 persons per square mile).

Note on Gender Bias: The traditional criteria specifically measure only the male main working population to determine the shift away from agriculture. This historical metric has faced criticism for ignoring female labor patterns in transitioning economies.

Urban Agglomerations (UAs) and Outgrowths (OGs)

To capture continuous urban expansion that spills across administrative boundaries, the Census uses the concept of an Urban Agglomeration (UA). A UA is a continuous urban spread constituting a town and its adjoining outgrowths.

  • Outgrowths (OGs): These are viable units like a railway colony, university campus, or military camp that sprout up just outside the statutory limits of a city or town but are physically contiguous with it.
  • UA Requirement: To be classified as an Urban Agglomeration, the core town (or at least one of the constituent towns) must be a Statutory Town, and the total population of the entire agglomeration must not be less than 20,000 (as per the latest available census data).

Grading Cities: Census Visual Classification (Tiers)

Once classified as urban, the Census traditionally grades these towns into six distinct classes based purely on population size:

  • Class I: 100,000 and above inhabitants (often referred to as Cities)
  • Class II: 50,000 to 99,999 inhabitants
  • Class III: 20,000 to 49,999 inhabitants
  • Class IV: 10,000 to 19,999 inhabitants
  • Class V: 5,000 to 9,999 inhabitants
  • Class VI: Less than 5,000 inhabitants (special administrative or tourist exceptions)

 

Recognizing that official data undercounts millions of people living in urban-like conditions, the Ministry of Housing and Urban Affairs (MoHUA), NITI Aayog, and the National Institute of Urban Affairs (NIUA) have proposed new frameworks to redefine “urban” India.

The latest proposed changes, frameworks, and structural transitions aim to map the country’s rapidly evolving urban landscape.

The Core Proposal: “Functional Urban Settlements”

To bridge the massive gap between geographical urbanization and rigid governance structures, the NIUA has recommended a new national settlement classification framework called Functional Urban Settlements.

  • The Mismatch: Under the existing framework, India recognizes only Statutory Towns (notified municipal corporations/committees) and Census Towns (villages meeting a population of 5,000, density of 400/sq km, and 75% male non-agricultural workforce).
  • The New Category: “Functional Urban Settlements” will capture peri-urban areas and rapidly transitioning villages that function like cities but are legally governed as rural panchayats.
  • Satellite-Driven Identification: Instead of relying strictly on administrative or population thresholds, the new framework proposes using Night-Time Light (NTL) data and satellite imagery to measure the intensity of built-up areas and illumination, creating a truer map of urban spread.

The Reality Check: While official census indicators peg India’s urbanization at roughly 31% to 36%, data mapping based on the UN’s Degree of Urbanisation framework suggests that nearly 84% of India’s population lived in functional urban settlements.

Uniform Reclassification of City Tiers

Historically, “Tiers” in India have been fractured—the Reserve Bank of India (RBI) uses one population scale for banking, while the Central Pay Commission uses an X, Y, and Z tier system for house rent allowances.

MoHUA is finalising a standardized, uniform classification of Tier-2, 3, 4, and 5 cities to drive differentiated policy, planning, and targeted investments:

  • Tier-1 Restructuring: Tier-1 metropolitan cities are being split into three distinct sub-categories based on population scale to better allocate massive infrastructure funds.
  • Tier-2 to Tier-5 Standardization: Smaller urban centers and fast-growing rural hubs are being assigned standardized parameters (combining population, local GDP, and corporate presence) to ensure they receive appropriate civic funding rather than being treated as simple rural zones.

Shift from “Towns” to “City Economic Regions” (CERs)

Economic and spatial planning is moving beyond strict municipal boundaries. The government is advancing the concept of City Economic Regions (CERs).

  • CERs map integrated supply chains, local labor markets, and surrounding satellite towns together as a single strategic economic hub.
  • Financial assistance and budget allocations are increasingly being tied to these functional regions rather than strict city-limit boundaries.

Mandate for “City Spatial and Economic Plans”

The Economic Survey emphasizes that future urban policy must focus on system performance. For all million-plus cities, a statutory 20-year City Spatial and Economic Plan (updated every 5 years) has been proposed. These plans introduce three non-negotiable criteria for urban development:

  1. A comprehensive mass transport network plan.
  2. A housing supply plan with fixed annual unit targets to prevent slum proliferation.
  3. A land-value capture framework explicitly linked to high-growth infrastructure corridors.

 

Geography Answer Writing Program

How are ocean currents generated?

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2023: How are ocean currents generated? Discuss their effects on coastal climates with special reference to the Pacific Ocean.

 

Ocean currents are continuous, directed movements of seawater generated by a complex interplay of forces acting upon the oceans. They act as the global conveyor belts of energy, significantly influencing Earth’s climate system.

Occasional events such as huge storms and underwater earthquakes can also trigger serious ocean currents, moving masses of water inland when they reach shallow water and coastlines. Earthquakes may also trigger rapid downslope movement of water-saturated sediments, creating strong turbidity currents.

Finally, when a current that is moving over a broad area is forced into a confined space, it may become very strong. On the ocean floor, water masses forced through narrow openings in a ridge system or flowing around a seamount may create currents that are far stronger than in the surrounding water, affecting the distribution and abundance of organisms

Ocean currents can be caused by wind, density differences in water masses caused by temperature and salinity variations, gravity, and events such as earthquakes or storms.

Surface currents in the ocean are driven by global wind systems that are fueled by energy from the Sun. Patterns of surface currents are determined by wind direction, Coriolis forces from the Earth’s rotation, and the position of landforms that interact with the currents. Surface wind-driven currents generate upwelling currents in conjunction with landforms, creating deepwater currents.

Currents may also be caused by density differences in water masses due to temperature (thermo) and salinity (haline) variations via a process known as thermohaline circulation. These currents move water masses through the deep ocean, taking nutrients, oxygen, and heat with them. The vertical motion of tides near the shore can also cause water to move horizontally, creating what are known as tidal currents.

 

Generation of Ocean Currents

The factors driving ocean currents can be broadly classified into primary forces (which initiate water movement) and secondary forces (which influence their path and direction).

Primary Forces

  • Insolation (Solar Heating): Differential heating at the equator causes water to expand. The water level near the equator is about 8 cm higher than in the middle latitudes, creating a very slight gradient that causes water to flow down the slope.
  • Planetary Winds: Trade winds and Westerlies push the surface water in the direction they blow. This friction between the wind and the water surface initiates surface currents.
  • Coriolis force: Due to Earth’s rotation, the Coriolis force deflects moving water to the right in the Northern Hemisphere and to the left in the Southern Hemisphere, giving rise to large circular loops called gyres.
  • Gravity: It pulls water down gradients created by differential heating or wind piling.

Secondary Forces

  • Temperature and Salinity Differences (Thermohaline Circulation): Cold, saline water is dense and sinks at polar regions, while warm, less saline water rises. This drives deep-ocean currents.
  • Shape of Coastlines: Landmasses obstruct and deflect the natural flow of water, guiding currents along continental margins.

General Effects of Ocean Currents on Coastal Climates

Ocean currents act as a planetary thermostat, transferring heat from lower latitudes to higher latitudes.

  • Temperature Regulation: Warm currents raise the temperature of coastal regions in higher latitudes, keeping ports ice-free (e.g., North Atlantic Drift in Europe). Conversely, cold currents moderate the heat of tropical coasts.
  • Precipitation: Warm currents supply moisture to the overriding winds, leading to rainfall on adjacent coasts. Cold currents cause atmospheric stability (thermal inversion), suppressing rainfall and leading to desiccation (desert formation).
  • Fog and Fishing Grounds: The convergence of warm and cold currents creates dense fog, which creates navigational hazards but also supports plankton growth, making these zones the world’s richest fishing grounds.

Pacific Ocean

The Pacific Ocean features two major subtropical gyres (North and South Pacific) that exert a profound influence on the climate of its surrounding landmasses.

The Western Pacific (Warm Currents)

  • Kuroshio Current (Warm): Flowing north along the coast of Taiwan and Japan, this current elevates winter temperatures along the Japanese coast and feeds moisture into onshore winds, causing high rainfall.
  • East Australian Current (Warm): It carries warm tropical water southward along the east coast of Australia. This ensures a humid, subtropical climate for cities like Sydney and Brisbane, contrasting sharply with the arid interior of the continent.

The Eastern Pacific (Cold Currents & Upwelling)

  • California Current (Cold): Moving southward along the western coast of North America, it keeps the coast of California remarkably cool during summer. The stability it introduces to the atmosphere contributes to the dry summer conditions of the Mediterranean climate in California and the aridity of the Sonoran Desert.
  • Peru (Humboldt) Current (Cold): This current flows northward along the western coast of South America. The cold water causes extreme atmospheric stability, completely blocking rainfall and resulting in the formation of the Atacama Desert—the driest non-polar desert on Earth.

The Mixing Zones

  • Oyashio Current (Cold) meeting Kuroshio Current (Warm): In the North-West Pacific, near the coast of Hokkaido (Japan), these two currents collide. The mixing creates dense sea fog, frequently disrupting maritime traffic, but it constitutes one of the most productive marine ecosystems and fishing zones in the world.

The El Niño-Southern Oscillation (ENSO) Phenomenon

  • During a normal year, the cold Peru current dominates the eastern Pacific.
  • During an El Niño year, the cold current is replaced by a warm counter-current. This drastically alters coastal climates: the hyper-arid Peruvian coast experiences devastating floods, while the western Pacific (Australia, Indonesia, and India) suffers from severe droughts due to shifted pressure belts.

Conclusion Ocean currents are vital components of global heat redistribution. In the Pacific Ocean, they establish a sharp climatic asymmetry between the eastern and western coasts. Understanding these dynamics is essential for analyzing global weather anomalies, monsoon variations in the Indian subcontinent, and the socio-economic vulnerabilities of coastal populations.

 

Geography Answer Writing Program

air masses and local winds

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Explain the relationship between air masses and local winds.

In climatology, the relationship between air masses and local winds is a classic study of scale, interaction, and modification.

While air masses represent macro-scale (synoptic) atmospheric phenomena covering thousands of kilometers, local winds are micro-scale to meso-scale systems confined to specific topographies. Their relationship is highly dynamic: air masses define the broad atmospheric canvas, while local winds either arise from their boundaries, modify their internal structures, or act as conduits that transport them.

Local Winds Generated by Air Mass Boundaries (Frontal Dynamics)

When two contrasting air masses meet, the boundary (front) generates sharp pressure and temperature gradients, which trigger localized, high-velocity winds.

  • Squall Lines and Gust Fronts: Ahead of an advancing Continental Polar (cP) air mass, the aggressive lifting of a warm Maritime Tropical (mT) air mass creates severe convective thunderstorms. The downdrafts from these storms hit the ground and spread out as a gust front—a violent, localized wind shift accompanied by a sharp drop in temperature.
  • Blizzards: The interaction between a blocking Arctic air mass and a passing mid-latitude cyclone creates a tight pressure gradient. This fuels localized, high-velocity winds that pick up loose snow, creating blizzard conditions.

Air Masses Restricting or Enhancing Local Thermal Winds

Local diurnal winds like land/sea breezes and mountain/valley breezes rely entirely on localized thermal gradients. Large-scale air masses can either suppress or amplify these winds.

  • Suppression by Stable Air Masses: If a region is dominated by a highly stable, subsiding air mass (such as an anticyclonic Continental Tropical (cT) mass), it creates a strong temperature inversion aloft. This upper-level stability dampens vertical air movement, weakening valley breezes or weakening the inland penetration of sea breezes.
  • Amplification by Cold Air Masses: When a cool Maritime Polar (mP) air mass hovers just offshore next to a sun-baked coastal landmass, the regional thermal contrast is maximized. This intensely amplifies the daily sea breeze, making it penetrate much further inland.

Local Winds as Agents of Air Mass Modification

Certain local winds are explicitly created when a large air mass encounters topographic barriers, transforming the air mass’s original characteristics through adiabatic processes.

  • Katabatic Winds (Gravity-Driven Cold Air): When a cold, dense Continental Arctic (cA) air mass pools over a high-altitude plateau (like Greenland, Antarctica, or the Alps), gravity pulls this heavy air down the slopes. This creates violent, localized cold winds like the Mistral (Rhône Valley) or the Bora (Adriatic Sea), which export the arctic air mass’s characteristics to coastal valleys.
  • Föhn / Chinook Winds (Adiabatic Warm Winds): When a moist air mass (such as mP) is forced over a mountain range, it drops its moisture on the windward side. As it descends the leeward side, it undergoes compressional heating at the dry adiabatic lapse rate .It emerges at the base as a hot, exceptionally dry local wind known as a Chinook (Rockies) or Föhn (Alps), completely modifying the local microclimate.

Local Winds as Transporters of Air Mass Characteristics

In many parts of the world, named local winds are simply the regional names given to the vanguard or edges of a migrating air mass.

  • The Harmattan: In West Africa, during winter, the dry Continental Tropical (cT) air mass over the Sahara pushes southward. The local wind that carries this dusty, ultra-dry air over the Gulf of Guinea is called the Harmattan.
  • The Loo: In the Indo-Gangetic plains during May and June, intense insolation creates an localized low-pressure trough. This draws hot, dry cT air from the Thar Desert, manifesting as the Loo—a highly localized, scorching afternoon wind.

Key Local Wind Regimes Dictated by the Siberian Continental Polar or Continental Arctic

It is characteristically bitterly cold, deeply dry, and highly stable .This causes the air to become incredibly dense and sink, forming a powerful anticyclone.

When this cold, dense air spills out of the Siberian reservoir, it is funneled by local topography into distinct regional wind regimes across East Asia.

The Winter Monsoon Winds (Northwest & Northeast Monsoon)

The primary outward rush of the Siberian High creates the East Asian Winter Monsoon. As the air moves, the Coriolis force and regional terrain split it into two distinct local wind flows:

  • The Northwest Monsoon (Northern East Asia): Sweeps across Northern China, Korea, and Japan. It is screamingly cold and dry, plunging temperatures across Beijing and Seoul well below freezing.
  • The Northeast Monsoon (Southern China & South China Sea): As the wind reaches lower latitudes, it is deflected by the Coriolis force to blow from the northeast, bringing dry, cool, clear winter conditions to Southern China and Vietnam.

The Karaburan (Black Blizzard) of the Tarim Basin

To the west and southwest, the outflow from the Siberian High encounters the massive deserts of Central Asia.

  • Mechanism: Cold air from the high-pressure system slips through gaps in the Tien Shan and Altai mountain ranges, rushing into the low-lying Tarim Basin (Taklamakan Desert).
  • Local Wind Dynamics: This creates the Karaburan, a violent, localized northeasterly wind. Because the incoming air is incredibly dense and fast-moving, it kicks up massive quantities of fine silt and sand, completely darkening the sky (hence “Black Blizzard”). It causes severe soil erosion and limits winter visibility to near zero.

The Buran / Purga of the Steppes

  • Mechanism: Across the open Russian steppes and Kazak plains, there are no mountain ranges to block the northern edge of the Siberian High’s circulation.
  • Local Wind Dynamics: When a low-pressure system moves along the periphery of the Siberian High, the pressure gradient spikes. This unleashes the Buran (or Purga when accompanied by snow)—a violent, freezing blizzard wind. It blows at gale forces, lifting existing snowcover into blinding sheets of ice-dust, creating life-threatening whiteout conditions across the plains.

The Hadashi / Oroshi Winds of Japan

When the Siberian High’s cold air mass travels eastward, it must cross the Sea of Japan before hitting the Japanese archipelago. This creates a brilliant two-step local wind and weather phenomenon:

  1. Thermodynamic Modification: The dry Siberian air mass moves over the warm Tsushima Ocean Current. It gets heated and humidified from below, transforming dynamically into an unstable Mp air mass
  2. Topographic Funneling (The Oroshi): As this modified air hits the central mountain spine of Japan, it is forced upward, dumping massive “sea-of-Japan effect” snow on the western slopes. Once the air clears the peaks and spills down the eastern leeward side toward Tokyo and the Pacific coast, it descends as a cold, dry, gusty local wind known as the Oroshi (or Hadashi, meaning “barefoot wind” due to its piercing coldness).
Current Affairs

Great Nicobar archipelago in the eastern Indian Ocean.

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Great Nicobar is the southernmost and largest island of the Nicobar archipelago in the eastern Indian Ocean. The Absolute Edge: It houses Indira Point, the official southernmost tip of Indian territory. Geopolitical Hotspot: It is strategically perched right next to the Strait of Malacca, one of the busiest maritime trade choke points in the world.

The mega-project spans roughly 166 square kilometers of land and is built around four foundational pillars:

International Container Transshipment Terminal (ICTT): Located at Galathea Bay, this deep-water port is designed to handle 14.2 million TEUs (Twenty-Foot Equivalent Units). It leverages a natural depth of over 20 meters to dock the world’s largest cargo ships. Greenfield International Airport: A dual-use civilian-military airport cleared for development to handle high-volume tourist traffic and accommodate advanced military surveillance aircraft. Gas and Solar Hybrid Power Plant: A 450 MVA power plant built to provide self-sustaining, low-interruption power to the new development. A New Smart Township: A sprawling urban development designed to support a projected influx of residents, service providers, tourism, and defense personnel.

Strategic & Economic Effects

The Indian government views the project as an initiative of paramount national importance. Its primary intended effects include: Geopolitical and Maritime Advantage: The island sits just 40 nautical miles from the Malacca Strait—one of the busiest shipping lanes in the world. The project significantly boosts India’s naval and defense surveillance presence in the Indo-Pacific, acting as a crucial maritime checkpoint. Economic Sovereignty: Currently, a massive chunk of India’s transshipment cargo is routed through foreign hubs like Colombo and Singapore. The ICTT will allow India to capture this revenue directly, reducing logistics costs and reliance on foreign ports. Global Tourism & Connectivity: Proximity to major Southeast Asian tourist hotspots (like Phuket and Langkawi) positions Great Nicobar to become a massive international transit and eco-tourism zone, driving major regional infrastructure growth.

Tribes: The Ancient Inhabitants

The island is home to two distinct indigenous communities whose lifestyles could not be more different, both heavily protected under strict tribal reserve laws: The Shompen: Classified as a Particularly Vulnerable Tribal Group (PVTG), the Shompen are a semi-nomadic, isolated group of hunter-gatherers living deep within the interior rainforests. They have historically avoided sustained contact with the outside world. The Nicobarese: Unlike the Shompen, the Nicobarese are traditionally settled horticulturists and marine fishermen. Originally living in coastal villages, a large portion of the population was forced to relocate inland to places like Campbell Bay after the devastating 2004 tsunami.

Impact on Indigenous Tribes

Encroachment on Tribal Reserves: The project overlaps with about 84 sq. km of the official Tribal Reserve, home to the isolated Shompen (a hunter-gatherer tribe) and the Nicobarese. Loss of Foraging Grounds: Although the government has firmly stated that no physical relocation of tribal habitations will happen and has expanded the overall reserve area elsewhere, activists argue that introducing hundreds of thousands of outsiders will permanently fracture the tribes’ isolation and alter their ancestral foraging ecosystems. Tribal Welfare -The Great Nicobar Project is fully aligned with the Shompen Policy of 2015 and the Jarawa Policy of 2004, which mandate that large-scale development proposals prioritize the welfare and integrity of Particularly Vulnerable Tribal Groups (PVTGs) and follow a structured consultation process. 

Biodiversity: An Ecological Wonderland

Designated as a UNESCO Biosphere Reserve, Great Nicobar is a massive hotspot of endemism (species found nowhere else on Earth) due to its dense, pristine tropical wet evergreen forests.

The Star Fauna: Nicobar Megapode: A unique, endangered bird that doesn’t sit on its eggs; instead, it builds massive mounds of decomposing vegetation and soil to act as a natural incubator.

Leatherback Sea Turtles: Galathea Bay on the island’s south coast is one of the world’s most critical nesting sites for these giant marine turtles. Other Endemics: The crab-eating macaque, Nicobar tree shrew, and reticulated python. Flora: The island boasts over 650 species of plants, including rare tree ferns and unique orchids that thrive in its perpetual equatorial humidity.

Ecological and Wildlife Impact

Massive Deforestation: The project requires diverting over 130 sq. km of pristine tropical rainforest. It is officially estimated that up to 7.11 lakh (711,000) trees will be chopped down in a phased manner across development cycles. Coral Reef Destruction: Building the port at Galathea Bay threatens thousands of rare coral colonies. Plans by the Zoological Survey of India (ZSI) to translocate over 16,000 coral colonies have drawn heavy skepticism from marine biologists, who point out that large-scale coral translocation has a historically poor track record globally.

Threat to Endemic Species: Great Nicobar is a global biosphere reserve home to unique wildlife like the endangered Leatherback sea turtle (which uses Galathea Bay as a primary nesting ground), the Nicobar macaque, the salt-water crocodile, and recently discovered endemic species like the Lycodon irwini wolf snake.

Government Safeguards and Current Status

To address these heavy critiques, the Ministry of Environment, Forest and Climate Change (MoEFCC) has established independent oversight committees to monitor pollution and biodiversity. The government has also initiated a Compensatory Afforestation plan, planting trees thousands of kilometers away in states like Haryana and Madhya Pradesh to offset the local forest loss. Furthermore, environmental assessments have mandated strict building standards that adhere to the National Building Code for earthquake-resistant infrastructure. The project is moving forward in a phased manner, with Phase I scheduled to run through 2035.

Extreme Seismic Vulnerability

The island sits directly on a highly volatile tectonic boundary (Seismic Zone V). It is profoundly prone to massive earthquakes and tsunamis. During the catastrophic 2004 Indian Ocean earthquake, the island didn’t just get hit by giant waves—the actual topography warped, causing parts of the coast to permanently subside (sink) into the sea by several feet. Ongoing seismic swarms in the Andaman Sea constantly remind scientists that a volcanic or tectonic event is never far off.

Risk Assessment and Disaster Management

The island lies in a seismically sensitive and cyclone-prone region. To address this, a comprehensive risk assessment study has been conducted covering both natural disasters (tsunamis, earthquakes, cyclones) and anthropogenic risks (industrial hazards, accidents). A vulnerability and disaster management plan has been prepared, ensuring preparedness for emergencies. Moreover, the reliance on a hybrid power plant (gas and solar) ensures resilience against disruptions while reducing carbon emissions.

Geography Answer Writing Program

Examine the formation of atmospheric tricellular

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Examine the formation of atmospheric tricellular circulation system. Describe how this system has been created considering the Earth a living planet.

The atmospheric tricellular circulation system is the primary mechanism by which the Earth redistributes solar heat from the equator to the poles. To examine this through the lens of a “living planet” (the Gaia hypothesis perspective), we must view these cells not as static mechanical loops, but as the planetary respiratory and circulatory system that maintains Earth’s thermal homeostasis.

Formation Mechanism

  • At the equator, the air near the surface is warm, winds are light, and the pressure gradient is weak. This region of monotonous weather is known as the doldrums. The warm air here rises, condensing into massive cumulonimbus clouds and thunderstorms, which release large amounts of latent heat as they form. The additional heat makes the air even more likely to rise, and provides the energy that drives the rising branch of the Hadley cell. This rising air reaches the stable tropopause, which blocks it from rising further, causing the air to diverge at upper levels and move poleward.
  • Due to the Coriolis force, this upper level poleward flow is deflected to the right in the Northern Hemisphere and to the left in the Southern Hemisphere, providing westerlies aloft (near the tropopause) in both hemispheres in the Hadley cell.
  • As air moves poleward from equatorial regions, it is constantly experiencing radiational cooling as it emits infrared radiation. Simultaneously, this air begins to converge and pile up as it approaches the mid-latitudes (around 30° latitude in both hemispheres). This convergence of air far above the surface increases the mass of air aloft, increasing the pressure at the surface. This increase in surface pressure results in a belt of high pressure centers called subtropical highsaround 30°N and 30°S. These latitudes are commonly known as the horse latitudes.
  • As this converging air above the subtropical highs slowly descends, it warms adiabatically by compression. This sinking air, dries the atmosphere creating generally clear skies and little rain. Over the oceans, weak pressure gradients in the high centers produce weak winds. Some of these lighter surface winds begin to move back toward the equator, and are deflected by the Coriolis force. This causes northeasterly winds in the Northern Hemisphere and southeasterly winds in the Southern Hemisphere in tropical regions. These winds are known as the trade winds.
  • Near the equator, the northeasterly and southeasterly trade winds converge at the surface at what is known as the intertropical convergence zone (ITCZ). Here, convergence further reinforces the rising branch of the Hadley cell.
  • Back at 30° latitude, while some of the air sinking along the subtropical highs goes equatorward to complete the Hadley cell, some  sinking air also moves poleward. This poleward moving surface air travels from from 30° to 60° and is again deflected by the Coriolis force. This results in the prevailing surface westerliesthat impact the mid-latitudes in both hemispheres. It is for this reason that weather moves west to east across the continental US. Often, this westerly flow is interrupted by high and low pressure systems that move with the mean surface flow. We’ll learn more about this in the next two chapters. As the surface air travels poleward from 30° to 60°, it collides with cold polar air moving equatorward. These air masses do not mix easily, and are separated by a boundary known as the polar front.
  • At the polar front, surface air converges and rises at the subpolar low, and storms and convection develop here. Some of this rising air goes all the way up to the tropopause where it moves back to 30° latitude and sinks at the subtropical high along with the descending branch of the Hadley cell. This circulation cell from 30° to 60° is known as the Ferrel cell, which is a thermally indirectcirculation in which cool air rises and warm air sinks.
  • Behind the polar front in the Northern hemisphere, cold surface polar air moves from the poles toward 60°. As the air moves equatorward, it is again deflected by the Coriolis force. In the Arctic regions, air typically flows from the northeast while in the Antarctic, air flows from the southeast. These are known as the polar easterlies. Along the polar front where cold polar air collides with warm air from the Ferrel cell, some of the rising air moves back toward the poles, which gets deflected as a westerly wind aloft. Eventually this air reaches the poles, sinks back to the surface, and flows back toward the polar front, which gives us thePolar cell.

The Tri-Cellular Structure

The system consists of three distinct cells in each hemisphere: the Hadley, Ferrel, and Polar cells. Their formation is driven by the interaction of differential solar heating, the Coriolis effect, and the pressure gradient.

The Hadley Cell (The Tropical Engine) Role- Acts as the primary heat pump, transporting energy from the tropics to the subtropics.

The Ferrel Cell (The Atmospheric Gear) –It creates the prevailing westerlies, moving heat and moisture toward the poles.

The Polar Cell (The Thermal Sink) –Serves as the planetary cooling system, pulling cold air away from the poles and replacing it with warmer air from lower latitudes.

The “Living Planet” Perspective: Gaia and Homeostasis

The Gaia Hypothesis

Proposed by James Lovelock , the Gaia hypothesis posits that the Earth’s surface, atmosphere, and biosphere function as a single, unified, self-regulating organism.

Life doesn’t just adapt to the environment; life actively modifies the physical environment (atmosphere, ocean salinity, temperature) to keep it suitable for its own survival.

The Analogy: If Earth were a living body, the atmosphere is its breath, the oceans are its circulatory system, and the forests are its lungs.

Example: The regulation of atmospheric oxygen levels at a steady ~21%. If it were much higher, the Earth would spontaneously combust; if lower, complex life could not breathe. Gaia theory argues that biological life (plants/plankton) manages this balance through photosynthesis and respiration.

Homeostasis (Planetary Equilibrium)

Homeostasis is the biological process by which a living system maintains internal stability while adjusting to external changes. In Earth science, it is the state of dynamic equilibrium.

The Mechanism: Homeostasis relies on Feedback Loops:

Negative Feedback (Stabilizing): These loops act like a thermostat. As the temperature rises, the system triggers a reaction that cools it down.

Example: Higher temperatures lead to more evaporation – more clouds – higher albedo (reflectivity) – cooling of the surface.

Positive Feedback (Destabilizing): These loops accelerate a trend, potentially pushing the system toward a “tipping point.”

Example: Warming melts polar ice – the dark ocean is exposed -heat absorption increases – more ice melts.

Viewing Earth as a living planet—where biological, chemical, and physical processes function in concert to maintain conditions for life—we can interpret these cells as vital organs:

  • Thermoregulation (Homeostasis): Just as a human body sweats to cool down or shivers to warm up, the tricellular system is the Earth’s mechanism for “planetary thermoregulation.” Without this movement, the equator would be uninhabitably hot and the poles perpetually frozen, rendering the planet’s biosphere largely inert.
  • Metabolic Exchange: The system is essentially a “respiratory system.” It facilitates the exchange of heat, moisture (water vapor), and kinetic energy across latitudes. This circulation allows for the creation of diverse biomes—from the lush rainforests fueled by the rising air of the Hadley cell to the arid deserts located beneath the sinking limbs of the same cell.
  • Dynamic Equilibrium: The system is self-correcting. If one region becomes too warm, the circulation intensity increases to redistribute that energy. This is a manifestation of the Le Chatelier principle applied to planetary science, where the system acts to counteract any local destabilizing force.

Conclusion

Tricellular system is the geographical manifestation of the Earth’s self-regulating capacity, proving that the atmosphere, hydrosphere, and lithosphere act in a symbiotic, life-sustaining, unified whole.

  • Climate Change as a “Systemic Fever”: Anthropogenic global warming acts like a pathogen introducing heat into a stable system. The tricellular system attempts to compensate, which manifests as intensified storm tracks, shifting jet streams, and expanded desertification zones (e.g., the expansion of the Hadley cell is causing arid zones to move into previously temperate regions).
  • Jet Streams as the “Circulatory Pathways”: The boundaries between these cells (the subtropical and polar jet streams) are the “highways” of the system. Their recent “meandering” or “blocking patterns” are symptoms of the planetary system struggling to maintain stability under the stress of rapid warming.
Geography Answer Writing Program

Discuss the mechanism and origin of Monsoon

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Discuss the mechanism and origin of Monsoon winds and explain the role of El Nino on Monsoon circulation.

Introduction The Indian Monsoon is a seasonal reversal of winds driven by complex thermal and pressure gradients. Rather than a single local event, it is a global atmospheric phenomenon involving the interaction between land, ocean, and the upper-tropospheric circulation. Its origin is explained by two primary schools of thought: the Classical (Thermal) theory and the Modern (Dynamic) theory.

Mechanisms and Origin of Monsoon Winds

The Classical Theory (Edmond Halley)

This theory views the monsoon as a giant land-sea breeze.

  • Summer Monsoon: During summer, the sun is overhead the Tropic of Cancer. The vast landmass of Asia (specifically the Tibetan Plateau) heats up intensely, creating a low-pressure zone. Simultaneously, the Indian Ocean remains relatively cooler (high pressure). Air moves from the high-pressure ocean to the low-pressure land, bringing moisture-laden winds.
  • Winter Monsoon: The process reverses in winter as the sun moves to the Tropic of Capricorn. The land cools rapidly (high pressure), while the ocean retains heat longer (low pressure), causing winds to blow from land to sea.

The Modern Theory (Dynamic)

Modern meteorology attributes the monsoon to the seasonal migration of planetary pressure and wind belts, specifically the Inter-Tropical Convergence Zone (ITCZ).

Shift of the ITCZ: During the summer, the ITCZ shifts north of the equator to create  Monsoon Trough. This draws the southeast trade winds across the equator. As they cross, the Coriolis force deflects them to the right, transforming them into the Southwest Monsoon.

The Role of Jet Streams:

  • Tropical Easterly Jet (TEJ): In summer, a powerful easterly jet stream flows at high altitudes (near the tropopause) from East to West over the Indian peninsula. It is believed to assist in the “pumping” of air, intensifying the low-pressure system over the Indian subcontinent, thereby strengthening the monsoon.
  • Sub-Tropical Westerly Jet (STWJ): During winter, the STWJ blows south of the Himalayas. For the monsoon to set in (summer), this jet must retreat northwards (tibetan plateau heating is a catalyst for this shift).

The Role of El Niño on Monsoon Circulation

El Niño is a periodic warming of the sea surface temperatures (SST) in the central and eastern equatorial Pacific Ocean, which disrupts the normal Walker Circulation and acts as a major atmospheric “spoiler” for the Indian Monsoon.

Mechanism of Disruption

  1. Normal Conditions (Walker Circulation): Under normal conditions, strong trade winds push warm water toward the Western Pacific (near Indonesia/Australia). This creates a low-pressure area (warm, rising air) in the west and a high-pressure area (cool, sinking air) in the east. This helps maintain the monsoon moisture transport toward India.
  2. El Niño Conditions: The trade winds weaken or reverse. Warm water surges toward the South American coast. The convective “rising air” center shifts from the Western Pacific toward the Central/Eastern Pacific.
  3. Impact on India: This shift triggers a descending (subsiding) air limb over the Indian Ocean and the Indian subcontinent. High-pressure conditions over India inhibit the moist convection required for rainfall, leading to weak monsoon performance, drought, or delayed onset.

The ENSO-Monsoon Link

  • Teleconnections: The atmosphere acts as a bridge. The change in Pacific heating alters the global pressure distribution, which pushes the Tibetan High (the upper-air high-pressure cell that drives the monsoon) out of position or weakens it.
  • Inverse Correlation: Historically, strong El Niño years have frequently correlated with sub-par rainfall in India. However, the correlation is not always linear, as other factors like the Indian Ocean Dipole (IOD) can sometimes offset the negative impacts of El Niño.

  Supplementary Factors: IOD and MJO

While El Niño is a major driver, the monsoon is also modulated by:

  • Indian Ocean Dipole (IOD): A “positive” IOD (warmer western Indian Ocean relative to the east) can act as a buffer against El Niño, effectively “pulling” the monsoon toward India even when Pacific conditions are unfavorable.
  • Madden-Julian Oscillation (MJO): An eastward-moving pulse of cloud and rainfall near the equator that can bring “active” and “break” phases to the monsoon cycle on a 30-60 day timescale.

Conclusion The Indian Monsoon is a highly resilient but sensitive system. While the origin of the monsoon is fundamentally tied to the thermal heating of the Tibetan Plateau and the shifting of the ITCZ, its variability is governed by complex global teleconnections. El Niño serves as a primary disruptor of the atmospheric circulation, proving that the rainfall in rural India is deeply interconnected with the ocean-atmospheric dynamics of the distant Pacific.

Geography Answer Writing Program

“The Himalaya is still rising.

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Introduction Unlike older, relict mountain systems like the Appalachians or the Urals, the Himalayas are young fold mountains born out of a colossal tectonic collision The Himalayas and the Tibetan Plateau to the north have risen very rapidly. In just 50 million years, peaks such as Mt. Everest have risen to heights of more than 9 km. The impinging of the two landmasses has yet to end. The Himalayas continue to rise more than 1 cm a year — a growth rate of 10 km in a million years! Scientists believe that the Eurasian Plate may now be stretching out rather than thrusting up, and such stretching would result in some subsidence due to gravity..

The Tectonic Setting: Continent-Continent Collision

The primary driving force behind the continuous rise of the Himalayas is explained by the theory of Plate Tectonics.

  • The Mechanism: The Himalayas are located at a convergent plate boundary, specifically characterizing a continental-continental collision between the northward-moving Indian Plate and the relatively stationary Eurasian Plate.
  • The Tethys Ocean Squeeze: Before the collision, the Tethys Ocean separated the two landmasses. As the Indian plate drifted north, the oceanic crust subducted beneath the Eurasian plate. Once the ocean closed, the two buoyant continental masses collided.
  • Crustal Shortening and Thickening: Because continental crust is too buoyant to subduct deeply into the mantle, the intense compressive forces caused the crust to crumple, fold, and fault. This led to massive crustal shortening and a doubling of the crustal thickness (reaching up to 70–80 km beneath the Tibetan Plateau), forcing the landmass upward.

Geological Processes Driving the Uplift

The continuous vertical growth of the Himalayas is sustained through a combination of structural faulting and deep-seated crustal dynamics:

Major Thrust Fault Systems

The immense compression has sliced the northern edge of the Indian plate into massive rock slices bounded by south-verging thrust faults. As the Indian plate continues to push north, it slips underneath these faults, stepping up and lifting the mountain blocks above them. From north to south, these zones include:

  • Indo-Tsangpo Suture Zone (ITSZ): The structural line marking the initial zone of collision.
  • Trans Himalayan Fault (THF): The line between Trans Himalayas and Himadri
  • Main Central Thrust (MCT): An older fault zone that propelled the crystalline rocks of the Greater Himalayas
  • Main Boundary Thrust (MBT): The fault zone primarily responsible for the uplift of the Lesser (Middle) Himalayas.
  • Main Frontal Thrust (MFT) / Himalayan Frontal Thrust (HFT): The youngest, southernmost fault system where the Shiwaliks (Outer Himalayas) meet the Indo-Gangetic plains. Active slip along the MFT is the principal contributor to the current rising of the outer mountain ranges.
  1. Isostatic Rebound
  • The towering Himalayan peaks undergo intense denudation (erosion) driven by glaciers, heavy monsoon rainfall, and powerful river systems.
  • As massive amounts of rock and sediment are stripped off the mountain tops and transported to the plains, the load on the underlying crust decreases.
  • To compensate for this loss of mass, the Earth’s mantle pushes the deep, buoyant continental “root” of the mountains upward to maintain isostatic equilibrium (akin to a ship rising in water as cargo is unloaded). This interaction between surface erosion and deep crustal processes accelerates the uplift.

Evidences of Continuous Rise

The assertion that the Himalayas are still rising is supported by robust empirical, geomorphological, and geophysical evidence:

  • Geodetic Data (GPS Measurements): High-precision satellite data show that the Indian plate is still moving northward into Asia at a rate of about 4 to 5 cm per year. This results in net Himalayan uplift rates ranging between 5 mm to 1 cm per year, depending on the specific structural zone.
  • High Seismic Activity: The Himalayan arc is one of the most earthquake-prone regions globally (classified under Zones IV and V of India’s seismic zoning map). Frequent earthquakes represent the sudden release of locked tectonic stress along active thrust faults, directly resulting in instantaneous physical displacement and vertical uplift.
  • Fluvial Geomorphology: Antecedent Drainage: Rivers like the Indus, Sutlej, and Brahmaputra existed before the mountains. As the land rose, these rivers carved deep, near-vertical gorges (such as the Indus Gorge) to maintain their original courses, proving that tectonic uplift outpaced the rivers’ lateral erosion.
  • River Terraces and Knickpoints: The presence of unpaired river terraces, steep waterfalls, and hanging valleys indicates structural rejuvenation, proving that the river beds are being uplifted repeatedly.
  • Marine Fossils at High Altitudes: The presence of Ammonite fossils (locally known as Shaligrams) in the high-altitude Spiti Valley and Muktinath (over 3,000 meters above sea level) proves that sedimentary rocks forming these peaks were once part of the marine Tethys ocean floor.

Conclusion The rising Himalayas serve as a living laboratory for structural geology and geodynamics. This continuous tectonic uplift is not merely a geological phenomenon; it actively dictates the South Asian monsoon patterns, feeds the perennial river systems sustaining over a billion people, and shapes the geo-hazard profile (landslides and earthquakes) of the entire Indian subcontinent. Developing infrastructure in this fragile, still-evolving landscape requires a deep synchronization with these ongoing earth processes.

 

Current Affairs

Explain the causes of glacial lake outburst flood.

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Explain the causes of glacial lake outburst flood. 2025

A glacial lake outburst flood (GLOF) is a release of meltwater from a moraine- or ice-dam glacial lake due to dam failure. GLOFs often result in catastrophic flooding downstream, with major geomorphic and socioeconomic impacts.

GLOFs have three main features:

  • They involve sudden (and sometimes cyclic) releases of water.
  • They tend to be rapid events, lasting hours to days.
  • They result in large downstream river discharges (which often increase by an order of magnitude).

Some of the largest floods in Earth’s history have been GLOFs. They have caused large-scale landscape change, and even altered regional climate by releasing huge quantities of freshwater to the oceans.

Today, GLOFs pose a risk downstream communities and infrastructure. In Peru alone, GLOFs were responsible for ~32,000 deaths in the 20th century. They have killed hundreds to thousands of people in other mountain regions (e.g. the Himalayas), and destroyed roads, bridges, and hydroelectric developments.

An increasing hazard

Importantly, the general global trend of glacier shrinkage through the 20th and 21st centuries has seen the number and size of glacial lakes increase, at the same time as human activities have expanded further into glaciated catchments. The study of how GLOFs occur and their impacts is therefore important for future hazard mitigation.

Glacial lake settings

There are two main settings in which glacial lakes form: (1) behind moraine dams, and (2) behind ice dams.

Moraine-dammed lakes

Moraine-dammed lakes form during periods of glacier retreat from a moraine. As a glacier margin retreats, water collects in the topographic low between the ice-front and the abandoned frontal and/or lateral moraine. Most existing moraine-dammed lakes (such as the Imja Tsho glacial lake in Nepal formed when mountain glaciers began to retreat from large moraine ridges constructed during the Little Ice Age

Moraine-dam failures

The failure of glacier and moraine dams depends on two main factors: (1) the integrity of the dam, and (2) the nature of trigger mechanisms

Moraine dams tend to be narrow and sharp-crested. As such, they are more likely to fail than broader dam types, such as ice-contact fans or landslides Most moraines are made up of loose, poorly sorted, permeable sediment, and some contain ice cores. Unconsolidated sediments are susceptible to failure, especially if saturated, while the melting of ice cores may cause moraines to subside over time. Despite these weaknesses, where a moraine is low, wide, and armoured by large rock material it may survive intact for hundreds or even thousands of years.

Displacement waves

Outburst floods in moraine-dammed settings are often caused by the sudden input of material into a lake causing displacement of water and overtopping of the dam. Displacement (or seiche) waves are commonly triggered by avalanches or rockfalls, or calving of a lake-terminating glacier.

Other triggers include, the rapid input of meltwater from an glacier upstream, heavy rainfall or snowmelt events that rapidly raise the lake level, or earthquakes that destabilise the moraine dam

 

Geography Answer Writing Program

Discuss major doctrines of departures in Humanism.

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Discuss major doctrines of departures in Humanism.

Scientific approaches like positivism, empiricism, and quantification tend to minimize the role of human awareness and knowledge. Humanistic geography, by contrast, especially tries to understand how geographical activities and phenomena reveal the quality of human awareness. Humanistic geography does not consider human being as an ‘economic man.

The propounder of humanistic geography (Tuan) explored five themes of general interest to geographers, namely:

  • geographical knowledge (personal geographies),
  • territory and place,
  • crowding and privacy,
  • livelihood and economics, and

Geographical Knowledge (Personal Geographies): Man is the superior form of life and has special capacity for thought and reflection. The primary task of humanistic geographers, therefore, is the study of articulated ideas (geographical knowledge). In general, broadly conceived knowledge of geography is necessary to biological survival. All animals must have it, and even the migratory birds have a mental map.

Territory and Place: Territory and place is also an important animal instinct. Some species of animals, like honeybee, tiger, lion, etc., defend their living space against intruders. They behave as they regard certain areas as their own; they appear to have a sense of territory. Human attitudes and attachment to territory and to place bear a clear resemblance to those of other animals. All animals, including human beings, occupy and use space.

Crowding and privacy : Crowding of a place leads to physical and psychological stress. It has been observed that the behaviour of animals at a crowded place becomes abnormal. Same is the case with man. Culture, social institutions and infrastructures, however, help in reducing these stresses. For example, people in crowded Hong Kong are no more prone to crime than people living in relatively spacious American, European and Australian cities. Contrary to this, in the Kalahari Desert, the Bushmen are crowded by choice, and biological indicators of stress are absent despite the high density at places where water is available.

Livelihood and Economics : Man sustains himself by doing some economic and social activities. All human activities appear to be economic and functional in the sense that they support the social system outside of which people cannot live. Whether it is worship of the sacred cow or ritual human sacrifice, they may be shown to have important economic consequences, and hence they are not beyond the economic rationale.

Religion : Religion is present at varying degree in all cultures. It appears to be a universal trait. In religion human beings are clearly distinguished from other animals.

The philosophical departures of Humanistic tradition includes:

Phenomenology is a philosophical approach that studies human consciousness and experience. Geographers began to adopt aspects of phenomenology in the 1960s and 1970s, partly to challenge the abstraction and generalization of prevailing spatial scientific approaches and partly to provide a more invigorated sense of human agency within geographical theory. Phenomenological approaches emphasize the significance of human subjectivity, the complexity of geographical knowledge production, and, in some quarters, the search for shared categories through which the world may be apprehended. In recent years phenomenological approaches have been critiqued for an overemphasis on human subjectivity, while some have questioned the extent to which phenomenological philosophy challenges the positivism of spatial science.

Existentialism is a philosophy that emphasizes individual existence, freedom and choice. It is the view that humans define their own meaning in life, and try to make rational decisions despite existing in an irrational universe. It focuses on the question of human existence, and the feeling that there is no purpose or explanation at the core of existence. It holds that, as there is no God or any other transcendent force, the only way to counter this nothingness (and hence to find meaning in life) is by embracing existence.

Idealism is the metaphysical and epistemological doctrine that ideas or thoughts make up fundamental reality. Essentially, it is any philosophy which argues that the only thing actually knowable is consciousness (or the contents of consciousness), whereas we never can be sure that matter or anything in the outside world really exists. Thus, the only real things are mental entities, not physical things (which exist only in the sense that they are perceived).

Idealism is a label which covers a number of philosophical positions with quite different tendencies and implications, including Subjective Idealism, Objective Idealism, Transcendental Idealism and Absolute Idealism, as well as several more minor variants or related concepts (see the section on Other Types of Idealism below). Other labels which are essentially equivalent to Idealism include Mentalist and Immaterialism.

Types of Idealism:

Epistemological Idealism asserts that minds are aware of, or perceive, only their own ideas (representations or mental images), and not external objects, and therefore we cannot directly know things in themselves, or things as they really are. All we can ever have knowledge about is the world of phenomenal human experience, and there is no reason to suspect that reality actually mirrors our perceptions and thoughts. This is very similar to the doctrine of Phenomenalism.

Actual Idealism is a form of Idealism developed by the Italian philosopher Giovanni Gentile (1875 – 1944) that contrasted the Transcendental Idealism of Kant and the Absolute Idealism of Hegel. His system saw thought as all-embracing, and claimed that no-one could actually leave their sphere of thinking, or exceed their own thought. His ideas were key to helping the Fascist party consolidate power in Italy, and gave Fascism much of its philosophical base.

Practical Idealism is a political philosophy which holds it to be an ethical imperative to implement ideals of virtue or good (it is therefore unrelated to Idealism in its other senses). Its earliest recorded use was by Mahatma Gandhi ,although it is now often used in foreign policy and international relations, where it purports to be a pragmatic compromise between political realism (which stresses the promotion of a state’s narrow and amoral self-interest), and political idealism (which aims to use the state’s influence and power to promote higher liberal ideals like peace, justice and co-operation between nations).

Geography Answer Writing Program

Brief analysis of Schaefer- Hartshorne debate

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Brief analysis of Schaefer- Hartshorne debate.

Although Hartshorne and Schafer both opposed the practice of emphasizing only one element in the systematic and the regional approach while ignoring the other. Their preferences or discourses led to a different inclination for the two in their final position. Even this tendency determines their methodological interests and positions.

Hartshorne’s regional geography. Hartshorne strongly treats the regional geography as the foundation, core and ultimate goal of geography. For example, he not only cites Hettner’s point of view, “only engaged in systematic geography work and does not cultivate regional geography, but such geographers also risk the complete departure from the geography base. People who do not understand regional geography not a true geographer”. Thus, ultimately, geography is attributed to “the science of describing and interpreting the variability between the various parts of the Earth as a human world”.

From this point of view, both Hettner and Hartshorne tend to regard regional geography as the core of geography. Although Hartshorne complained too many critics of the Nature of Geography and ignored his emphasis on systematic geography, his expression of the nature of geography, his  narrative history of thoughts. The interest finally reflects that he still puts the “center of gravity” of geography on regional research. That is to say, although the formal rules and purpose requirements of the methodology make him reject the dualism, his personal interest and the weight of the historical view of thought are added to the regional geography, which in essence leads him to the geographical nature. The understanding is still focused on regional geography.

Schaefer’s systematic geography. Schaefer draws on the examples of the development of natural science and economics and will seek the law of space. To do the ultimate goal of geography, we believe that “geography must pay attention to the spatial arrangement of regional phenomena, not the phenomenon itself; spatial relations are specialized fields of geographers, and non-spatial relations are specialized in other fields” (Schaefer, 1953). On this basis, Schaefer criticized the regional school’s view that the regional geography application is regarded as the core of geography and that the application is also the implementation of the law, rather than the study of unique regions.

Differences between Hartshorne and Schafer’s geography

Hartshorne’s view of geography history. Hartshorne’s geography of history is concentrated in his 1958 documentary on the concept of geography. In this classic paper, Hartshorne traces the understanding of the concept of geography from Kant to Hettner, and divides this history into different stages. On the basis of different stages of the development, the views are basically consistent with general conclusions (Hartshorne, 1958). From this division, Hartshorne thinks that the evolution of the history of geography depends on the discipline itself and the modelling of geographers. He tries to find similarities between Kant, Humboldt, and Hettner. Therefore, Hartshorne’s geography history view is “geography (home)” and seeks unity.

It seems that even in the case of Schafer’s fierce criticism of his methodology, Hartshorne emphasis is still on the subjective nature of geography: the region, and more emphasis on the importance of this “discipline characteristics.” From the 1939s to the 1959s, during the 20 years of Hartshorne’s main content, his basic ideas on the methodology of geography have not changed much. This paper of 1958 may verify the correctness of Schafer’s criticism from another level. In a sense, Schaefer’s critique and some of the shortcomings of the intellectual history knowledge exposed in the process prompted Hartshorne to further strengthen his methodological beliefs.

Schaefer’s view of geography history. Contrary to Hartshorne’s first person who sees Kant as the concept of determining geography, Schaefer believes that Kant is the initiatorof the exception theory. Schaefer believes that Kant-Hettner-Hartshorne is in the same vein and forms the historical chain of geography “exceptionalism”. Hettner not only jumps out of Kant’s circle but also coincided with Kant’s geography and delighted that their authority and great prestige have made the “exceptional theory” deeply in grained. This has caused geography to be “non-scientific and even anti-scientific.” Therefore, Schaefer’s geography history view is “the (integral) science” standard, and it is considered that there is a major difference in geography history rather than a unified theme, which is completely contrary to Hartshorne’s and regional schools. Now, Schaefer is clearly a staunch supporter of “scientism,” and the actual history of geography has denied his extreme “scientism” arguments (such as humanistic geography).Therefore, another main reason for this controversy lies in two different positions and perspectives on the history of geography: Schaefer’s perspective is based on the current state of geography and other trends in scientific development and is critical to history while Hartshorne’s perspective is based on the historical characteristics of the discipline. It is mainly affirmative of history and believes that the history of the discipline is basically unified. Inheriting this historical characteristic is to maintain the basic nature of geography, and that this is the direction of geographers’ efforts. On the whole, it can be said that different values (personal interests, preferences and purposes) and historical views determine the difference in methodology.

The reverberation of the debate. The net outcome of Schaefer-Hartshorne Debate was that geography had come increasingly to be viewed as a science requiring the use of the scientific method’ so that like other sciences, it could also develop laws and theories relevant to its field of study .This brought about a distinctive shift in emphasis from ‘regional’ to ‘systematic’ studies. This meant that geography there after began increasingly to be viewed in a nomothetic perspective. This also involved a shift from ‘areal’ to ‘locational’ studies; from ‘absolute’ to ‘relative’ locations; and from ‘areal differentiation’ to ‘spatial interaction’ .With the rise of the “quantitative revolution” wave, the regional school gradually lost its momentum. However, the status of positivist geography emphasizes systematic ideas and methods which is not strong. Positivism geography has almost the same experience as the regional school of the 1960s. But it is worth noting that in the 1980s, there were some renewed calls for the revival of “regional geography” in the geography community. Representative of the American Association of Geographers, John Hart (1979) argued on his paper entitled “The Highest Form of Geographer Art”, even caused him and the positivist debate on behalf of the president of the association. It is worth pondering that this argument is strikingly similar argument with Schaefer, but the impact is relatively small. It can be said that it is the aftermath of the regional and systematic dualism debate.

Unlike most other presidents’ speeches, Hart’s paper on this speech has caused much controversy. In this article, Hart reiterates the traditional view that geography focuses on the study area, and criticizes the “scientism” formed in the “quantitative revolution” (i.e. “narrowly believe that only the use of mathematical (quantitative) methods is correct, only in ‘scientific’” advocacy), and “geography cannot lose its vitality in order to excessively pursue ‘science’. Thus, systematic geography provides a general theory of regional studies, and regional geography validates this theoretical basis from reality. The regional thinking is the basic theme of the different branches of geography; the highest form of geographer art is to produce a vivid description that is easy to understand and evaluate… a geographer should respect the philosophical positions, values, and beliefs of other geographers and avoid Forcing others; geography and geographers should be more tolerant than coercive and have a portal” (Hart, 1982).Compared with the previous regional and systematic dualism debate, Hartshorne’s article and its controversy have a much lesser influence. In fact, it may be only the aftermath of “Schaefer-Hartshorne debate”, which is the regional and systematic dualism.

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