changes in critical geographical features and biota

How water-bodies, ice-caps, coasts, vegetation and animal life are being altered by climate change and by direct human modification, and why the causes, costs and remedies of those changes are disputed.

What it is

The syllabus phrase covers two linked things. "Critical geographical features" are the physical elements of the earth's surface whose condition governs the habitability of a region — rivers, lakes, lagoons, wetlands and aquifers; glaciers, snowfields, permafrost, sea ice and the polar ice sheets; coastlines, deltas, estuaries, reefs and low-lying islands. "Biota" is the living cover that depends on them: flora and fauna, whether terrestrial, freshwater or marine. The Commission's wording adds the operative clause — "and the effects of such changes" — which signals that the paper wants mechanism and consequence, not inventory.

The subject sits between two families of cause that must be kept analytically apart. The first is anthropogenic climate change: warming of the atmosphere and ocean, thermal expansion of sea water, loss of land ice, changes in monsoon variability and in the intensity of tropical cyclones. The second is direct human modification of the feature itself: damming and diverting rivers, pumping aquifers, reclaiming wetlands, mining sand, clearing mangroves for aquaculture or ports, introducing invasive species, and fragmenting habitat with roads and canals. Most observed change in India is the product of both, in proportions that are genuinely disputed.

Institutionally the field is anchored in assessment bodies rather than in a single statute. Globally, the Intergovernmental Panel on Climate Change compiles the physical evidence, including its Special Report on the Ocean and Cryosphere (2019) and the Sixth Assessment cycle; the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services performs the same function for living systems. Treaty architecture runs through the Ramsar Convention on Wetlands, the Convention on Biological Diversity and its Kunming-Montreal Global Biodiversity Framework, the UN Framework Convention on Climate Change, and the UN Convention on the Law of the Sea, which fixes maritime zones to coastal baselines. In India the corresponding machinery includes the Central Ground Water Board's periodic assessment of aquifers, the Forest Survey of India's biennial forest and mangrove reporting, the India Meteorological Department's cyclone monitoring, the Wildlife (Protection) Act of 1972 and the Biological Diversity Act of 2002, and the Wetlands (Conservation and Management) Rules of 2017.

Why it is contested

The first contest is attribution, and it is not academic. If the shrinking of a lake or the salinisation of a delta is read primarily as a climate signal, the remedy is global mitigation plus local adaptation finance, and local authorities are absolved. If it is read primarily as local mismanagement, the remedy is regulation of pumping, encroachment, sand mining and effluent, and the political cost falls on identifiable domestic constituencies. The Aral Sea, drained largely by Soviet-era irrigation withdrawals from the Amu Darya and Syr Darya, and Loktak in Manipur, whose hydrology was transformed by the Ithai barrage, show how far a water-body can be altered with little help from the atmosphere. Equally, glacier retreat across most of the Himalaya and the rise in ocean heat content are not explicable by local land use. A candidate who collapses everything into "climate change" loses the analytical distinction the paper is testing.

The second contest is between present livelihoods and the physical basis of future ones. The decline of the Ganga plain's groundwater is the clearest case: assured procurement, subsidised or free electricity for pumping and a paddy-wheat rotation in Punjab, Haryana and western Uttar Pradesh underwrote national food security and rural incomes, and simultaneously drew down the aquifer that makes those harvests possible. Restraint means lower incomes now for water later, and the losers are concentrated and organised while the beneficiaries are diffuse and future. The same structure recurs on the coast, where mangroves buffer storm surge but occupy land wanted for ports, aquaculture and housing, and in the Himalaya, where run-of-river hydropower is defended as low-carbon energy in a seismically active, glacially unstable landscape.

The third contest is distributional and international. Small island developing states contribute a negligible share of cumulative emissions and face the loss of territory, freshwater lenses and, arguably, statehood; they press for mitigation, adaptation finance and compensation for loss and damage. Large emitters, historical and current, resist open-ended liability. Within countries the same asymmetry repeats: in the Sundarbans and on the Kerala and Odisha coasts it is the poorest households on the most exposed land that absorb erosion and salinity first.

The fourth contest is over conservation itself. Protecting biota through inviolate protected areas conflicts with the recognised rights of forest-dwelling communities and with the reality that species now need to move as climatic zones shift, which fixed reserves do not accommodate. Data are also disputed: headline figures on wildlife decline rest on monitored population indices whose method is criticised, forest-cover accounting that counts plantations alongside natural forest is criticised for masking degradation, and projections of sea-level rise carry a wide range precisely because ice-sheet behaviour is poorly constrained.

The competing positions

Those who foreground global climate attribution — the IPCC assessment community, the Alliance of Small Island States, and most climate scientists working on the cryosphere and ocean — argue that the changes are systemic, already committed for decades by past emissions, and beyond the reach of any local regulator. Sea-level rise, warming sea surface temperatures and glacier mass loss are basin- and hemisphere-scale phenomena; treating them as local failures both misdiagnoses the cause and lets emitters escape. On this view the priorities are deep mitigation, predictable adaptation finance, and a loss-and-damage mechanism with real money in it.

Those who foreground local drivers — many Indian hydrologists, wetland ecologists and administrators, and much of the river-basin literature — argue that the tractable variable is almost always domestic. Aquifers fell because pumping was unpriced, lagoons silted because catchments were deforested and mouths blocked, floods worsened because floodplains were built on, and species were lost to habitat conversion and invasive plants such as lantana and prosopis long before warming became measurable. Their case is that Chilika's partial recovery after its sea mouth was reopened demonstrates what local hydrological intervention can achieve, and that invoking a global cause becomes an alibi for inaction.

On conservation practice, the exclusionary or fortress position holds that core habitat must be free of human use if large fauna are to survive, and cites tiger recovery in well-protected reserves. The rights-based position, grounded in the Forest Rights Act and in community conservation experience, holds that securing tenure produces better outcomes at lower coercive cost and that landscape connectivity beyond reserve boundaries matters more than the boundaries themselves. On coasts, an engineering school favours seawalls, groynes and reclamation; a nature-based school favours mangrove and dune restoration, arguing that hard structures displace erosion rather than end it. For island states, one strand argues for elevation, land reclamation and in-situ adaptation to preserve sovereignty and identity; another accepts planned migration with dignity, as in Tuvalu's arrangement with Australia and Kiribati's land purchase in Fiji, and presses for legal recognition of maritime zones and statehood even if territory becomes uninhabitable.

How it developed

The modern framing began with the wetlands convention agreed at Ramsar in 1971 and the Stockholm conference the following year, which established that habitat and species loss were international questions. India legislated on wildlife protection in the same period and later added forest conservation and, after the Rio conference of 1992, biodiversity legislation. Rio itself produced the two conventions — on climate and on biological diversity — that still structure the argument.

Meanwhile the drivers accelerated. Post-independence dam building and canal irrigation reordered river hydrology; the Green Revolution and rural electrification from the late 1960s onward turned groundwater from a supplement into the mainstay of Indian irrigation, with abstraction rising through the 1980s and 1990s until satellite gravimetry and official assessment both recorded severe depletion in the north-west. Coastal Kerala, Tamil Nadu and the Sundarbans saw mangrove conversion and embankment; wetlands inside cities were built over.

From the late 1980s the scientific machinery matured: the IPCC was established in 1988, satellite records of Arctic sea ice accumulated from 1979, and biodiversity hotspot mapping identified the Western Ghats, the Himalaya, Indo-Burma and Sundaland as global priorities, all touching India. Successive assessments hardened the cryosphere and ocean findings, culminating in the ocean and cryosphere special report and the Sixth Assessment cycle. India's response ran through a national climate action plan in 2008 with dedicated missions on water and the Himalayan ecosystem, wetland rules in 2017, aquifer-focused schemes, and mangrove and wetland programmes announced in the mid-2020s. Internationally the period produced the Paris Agreement, the 2022 global biodiversity framework with its target of conserving thirty per cent of land and sea by 2030, and the agreement at successive conferences of parties to establish and operationalise a loss-and-damage fund. Recent events — the Sikkim glacial lake outburst that destroyed a hydropower project, record low Antarctic sea-ice extent, repeated coral bleaching — have kept the subject in the news.

Where it stands

The direction of change is not seriously disputed; the rates and the local expression are. Global mean sea level is rising and accelerating, with projections for 2100 spanning roughly a third of a metre to about a metre depending on emissions, and higher outcomes not excluded if marine ice-sheet instability in West Antarctica proceeds faster than modelled. Himalayan glaciers are losing mass overall, though the Karakoram has behaved anomalously, and the downstream question — whether flows first rise, then peak, then fall — remains unsettled and matters enormously for the Indus and the Ganga's upper tributaries. Sea surface temperatures in the north Indian Ocean are rising, and there is credible evidence of more intense and more rapidly intensifying cyclones and of increased cyclone activity in the Arabian Sea, though frequency trends are noisier than intensity trends.

Domestically, the Gangetic aquifer decline continues in its north-western reach, with contamination by arsenic and fluoride compounding the quantity problem; crop diversification away from paddy is announced more often than achieved. Wetland and lagoon management has improved in specific well-studied cases and remains weak in aggregate. Forest cover is reported stable or rising while ecologists dispute whether natural forest quality is being maintained. Legally, the status of maritime zones and of statehood for territory that becomes uninhabitable is open, with international tribunals only beginning to opine on states' climate obligations. Financing for adaptation and for loss and damage remains far below stated need.

Taking a view

The distinction that earns marks is between driver, feature and effect, and between global and local drivers within that chain. Name the mechanism explicitly: warmer sea surface temperature and deeper ocean heat content supply latent heat and reduce the cooling effect of storm-induced mixing, which is why cyclones intensify faster; thermal expansion plus land-ice melt raises sea level, which drives not only inundation but saline intrusion into aquifers and paddy land, higher storm-surge reach, and coastal erosion; groundwater over-abstraction lowers the water table, raises pumping cost, dries shallow wells first and therefore hits small farmers before large ones. A question about island nations wants the freshwater lens, the reef, the fishery, maritime entitlements and migration, not only the image of submergence.

The usual trap is to write a general climate-change essay. The paper is asking about geographical features, so the answer should be grounded in named features and their specific physics — the Sundarbans, Chilika, Loktak, the Gangetic aquifer, Gangotri, the Lakshadweep reefs, the Arabian Sea. The second trap is the undifferentiated list of effects. Sort them: physical, ecological, economic, and where relevant legal or geopolitical.

Take a position rather than balancing. A defensible one, briefly stated, is that mitigation is where the ultimate causes lie but local governance of water, coasts and habitat is where the tractable levers are, and that treating global attribution as a reason to defer domestic reform is the more damaging error in the Indian case. If you argue instead that adaptation without mitigation is futile beyond a certain warming, say so and accept the implication — that the priority is finance and compensation, not local regulation. Either view is answerable; refusing to choose is not.