Agriculture, Climate Change and GM Crops

A real question on this chapter rarely asks "does agriculture affect climate change". It asks something narrower: which specific activity inside Indian agriculture emits the most, methane from livestock or nitrous oxide from fertilised soil, and it separately tests whether you know that Bt cotton remains India's only commercially cultivated GM crop while GM mustard's legal status is still sub judice, not settled either way. Both traps punish a general answer where a precise, current one is expected.

Agriculture's role in and vulnerability to climate change

Agriculture is not a minor player in India's own greenhouse gas accounting. Under India's 4th Biennial Update Report (BUR-4) to the UNFCCC, submitted 30 December 2024 with a national inventory year of 2020, the agriculture sector emitted 406 million tonnes of CO2 equivalent, or 13.72% of India's total emissions (excluding land use, land-use change and forestry), making it the second-largest emitting sector after energy. Within that agricultural total, the BUR-4 breaks emissions down by source, and this breakdown is the exact detail a precise question tests: enteric fermentation in livestock (methane from ruminant digestion) accounts for 54.84%, the single largest share; agricultural soils, primarily nitrous oxide released from nitrogen fertiliser application, account for 23.26%; rice cultivation, methane from flooded paddy fields, accounts for 16.68%; and manure management contributes the remaining 3.22%. The exam-relevant grouping is: methane comes overwhelmingly from livestock digestion and rice paddies (anaerobic decomposition in flooded soil), while nitrous oxide comes from fertilised soil, two distinct gases from two distinct agricultural activities, not a single undifferentiated "farm emissions" category.

The same sector that emits is also acutely vulnerable to the warming it contributes to, and this is the half of the question examiners use to test whether a candidate confuses cause and consequence. Responding to the Lok Sabha on 11 December 2023, the Ministry of Environment, Forest and Climate Change cited ICAR's National Innovations in Climate Resilient Agriculture (NICRA) project's projections, without adaptation measures: rainfed rice yields could fall 2 to 20% by 2050 and 10 to 47% by 2080; irrigated rice, better buffered, only 2 to 3.5% by 2050 and 2 to 5% by 2080; wheat, the crop ICAR flags as most exposed, could fall 8.4 to 19.3% by 2050 and 18.9 to 41% by 2080; and kharif maize 10 to 19% by 2050 and over 20% by 2080. Wheat's particular sensitivity comes from its narrow optimal temperature window during grain-filling, a terminal heat stress that shortens the grain-filling period and lowers yield even with adequate water and nutrients. The parliamentary answer named rice, wheat and maize specifically as the crops most affected, a detail a statement question can quietly swap for a different crop list.

Sustainable and conservation agriculture

Conservation agriculture is not one technique but a package built around three linked principles: minimal mechanical soil disturbance, permanent soil cover through crop residue retention, and diversified crop rotation. The most heavily tested component is zero tillage (also called no-till or zero-till farming): sowing the next crop's seed directly into the untilled soil and previous crop's residue using a specialised zero- till seed drill, skipping the ploughing and harrowing that conventional tillage requires between crops. This matters most in India's rice-wheat cropping belt of Punjab, Haryana and western Uttar Pradesh, where farmers must sow wheat within a narrow window immediately after rice harvest; zero tillage removes the weeks conventional tillage would otherwise consume, while also cutting the diesel and labour cost of field preparation.

The Indian government has backed this transition through the Sub-Mission on Agricultural Mechanization, which subsidises resource-conservation equipment including zero-till seed drills, laser levellers, rotavators and Happy Seeders (a machine that sows wheat directly through standing rice stubble). A dedicated Central Sector Scheme for Promotion of Agricultural Mechanization for In-Situ Management of Crop Residue, launched in 2018 for Punjab, Haryana, Uttar Pradesh and the NCT of Delhi, specifically funds this machinery so farmers manage rice residue in the field rather than burning it, tying conservation tillage directly to stubble-burning mitigation rather than leaving it as a separate soil-health measure. Both schemes sit inside the broader National Mission for Sustainable Agriculture (NMSA), one of the eight missions under the National Action Plan on Climate Change, whose objectives explicitly include soil health management based on soil-test data, soil and moisture conservation, and efficient water management aimed at "more crop per drop". Crop rotation, the third pillar, breaks pest and disease cycles that build up under continuous monocropping and, when a legume is included in the rotation, replenishes soil nitrogen through biological fixation rather than synthetic fertiliser, directly reducing the nitrous oxide source described above.

Biochar

Biochar is a stable, carbon-rich solid produced by heating biomass (crop residue, wood waste, manure, or other organic material) through pyrolysis: thermal decomposition in an oxygen-limited or oxygen-free environment, typically at temperatures between roughly 300 and 700 degrees Celsius, as distinct from ordinary combustion, which occurs in the presence of oxygen and releases carbon back to the atmosphere as CO2. Lower pyrolysis temperatures (around 300 to 400 degrees Celsius) tend to produce a more acidic biochar, while higher temperatures (closer to 700 degrees) produce a more alkaline one, so a given biochar's soil effect depends on how it was made, not just what it was made from.

Biochar's climate role rests on a specific mechanism: converting biomass into biochar locks a large share of its carbon into a chemically stable (recalcitrant) form that resists microbial decomposition for a very long time, peer-reviewed estimates put the more stable fraction's residence time at several hundred years, rather than the years to decades over which that same biomass would otherwise decompose and release its carbon as CO2 or methane. This is the distinction to hold onto for the exam: biochar does not prevent carbon emission, it changes the timescale over which stored carbon returns to the atmosphere, converting a fast biological carbon cycle into a much slower one. Applied to soil, biochar also functions as a soil conditioner in its own right, independent of its climate role: its porous structure and high cation exchange capacity improve a soil's ability to retain both water and nutrients (documented increases in water-holding capacity and cation exchange capacity in sandy and loamy soils), while also supporting greater microbial enzyme activity. In the Indian context, biochar is increasingly discussed as a dual-purpose answer to crop residue burning and declining soil health simultaneously: residue that would otherwise be burned in the field, releasing its carbon immediately along with particulate pollution, can instead be pyrolysed into biochar and returned to the same soil as a slow-release carbon store and conditioner.

Genetically modified crops in India

Bt cotton remains India's only genetically modified crop approved for commercial cultivation, cleared by the Genetic Engineering Appraisal Committee (GEAC) in 2002. It carries a gene from the soil bacterium Bacillus thuringiensis that expresses a toxin lethal to the cotton bollworm, reducing dependence on chemical pesticide sprays against that pest specifically. Government data cited by the Ministry put Bt cotton's share of India's total cotton-growing area at over 96%, making it the default cotton variety in practice even though it remains, formally, the sole approved case rather than one of several.

The GEAC is the statutory body that approves this and any other GM crop's environmental release. It functions under the Rules for the Manufacture, Use, Import, Export and Storage of Hazardous Microorganisms or Genetically Engineered Organisms or Cells, 1989, framed under the Environment (Protection) Act, 1986, and sits within the Ministry of Environment, Forest and Climate Change. GEAC clearance is a mandatory, non-optional gate before any GM crop can be released into the Indian environment, whether for field trial or commercial cultivation, and courts have held that GEAC's decisions remain open to judicial review, a point made explicit in the mustard litigation below.

A third crop worth knowing for contrast is Bt brinjal: GEAC itself cleared it for commercial release, but the then Environment Minister imposed an indefinite moratorium in February 2010, before any commercial cultivation began, after a round of public consultations raised unresolved safety concerns. That moratorium remains in force, so Bt brinjal is a case of a GEAC-approved GM crop that never reached the market, a different regulatory outcome from Bt cotton (approved and cultivated) and from GM mustard (approval recommended, cultivation stayed by court order, described next). Illegal, unapproved cultivation of both herbicide-tolerant Bt cotton and Bt brinjal has been separately reported in several states, a compliance failure distinct from the formal regulatory status of any of these three crops and worth not conflating with it in an answer.

GM mustard (DMH-11, Dhara Mustard Hybrid 11), developed by scientists at Delhi University, would be India's first GM food crop if it clears every remaining hurdle, and its status is genuinely unsettled rather than approved or rejected. The GEAC recommended DMH-11 for environmental release in October 2022, but the Supreme Court had already put the matter under a status quo order from 3 November 2022, meaning no commercial release could proceed while the case was heard. On 23 July 2024, a two-judge Supreme Court bench (Justices B.V. Nagarathna and Sanjay Karol) delivered a split verdict: Justice Karol upheld GEAC's approval process as lawful, while Justice Nagarathna held that GEAC had relied on foreign safety studies without adequate India-specific data and had not applied the precautionary principle correctly. Because the two judges disagreed, the matter was referred to a larger three-judge bench, and the same July 2024 order directed the central government to frame a national policy on GM crops, covering research, cultivation, trade and commerce, in consultation with states, farmer groups and independent experts. A three-judge bench (Justices Abhay S. Oka, Sudhanshu Dhulia and Ujjal Bhuyan) began substantive hearings from 15 April 2025. As of this note, no final Supreme Court ruling on DMH-11's environmental release and no completed national GM crop policy have been confirmed: commercial cultivation of GM mustard remains stayed and the matter remains sub judice, a live regulatory question rather than a settled fact, and this note deliberately does not state a resolution it cannot verify.

Exam angle

This chapter tests two different skills depending on the section. The climate-change section rewards knowing agriculture's exact emission breakdown by source (livestock enteric fermentation, then agricultural soils, then rice, then manure, in that order by share under BUR-4) rather than a vague "farming causes methane and nitrous oxide" answer, and separately rewards distinguishing agriculture as an emitter from agriculture as a victim of the warming it contributes to. The conservation agriculture and biochar sections reward mechanism, not just vocabulary: knowing that zero tillage skips soil disturbance rather than skips fertiliser, and that biochar's climate value comes from slowing carbon's return to the atmosphere rather than from preventing emission outright. The GM crops section is the sharpest current-affairs trap in the chapter, because the honest answer is "unresolved": a question may present GM mustard as already commercially approved (it is not) or as permanently banned (it is not that either); the accurate position is conditional GEAC clearance for environmental release, under an unresolved Supreme Court challenge, with commercial cultivation on hold. Anchor any answer to Bt cotton's confirmed 2002 approval and treat GM mustard's status as current and subject to change, not as settled history.

Quick revision points

• India's agriculture GHG share (BUR-4, 2020 data, submitted 30 Dec 2024): 406 MtCO2e, 13.72% of India's total (excluding LULUCF). Breakdown: enteric fermentation (livestock methane) 54.84%, agricultural soils (fertiliser N2O) 23.26%, rice cultivation (methane) 16.68%, manure management 3.22%.
• Climate vulnerability (ICAR-NICRA, cited to Lok Sabha 11 Dec 2023, no-adaptation projections): wheat down 8.4-19.3% by 2050 (worst-hit major crop); rainfed rice down 2-20% by 2050; irrigated rice down 2-3.5% by 2050; kharif maize down 10-19% by 2050. Rice, wheat and maize named as most-affected crops.
• Conservation agriculture: zero tillage, residue retention, crop rotation. Government-subsidised via the Sub-Mission on Agricultural Mechanization and the 2018 in-situ crop-residue-management scheme (Punjab, Haryana, UP, Delhi); both sit under the National Mission for Sustainable Agriculture.
• Biochar: made by pyrolysis (biomass heated without oxygen, roughly 300-700 degrees C); locks carbon in a stable form for centuries rather than preventing its release; also raises water-holding capacity and cation exchange capacity in soil.
• Bt cotton: GEAC-approved 2002, India's only commercially cultivated GM crop, over 96% of cotton area.
• GM mustard (DMH-11): GEAC recommended environmental release October 2022; Supreme Court status quo order since 3 November 2022; split verdict 23 July 2024 referred the case to a three-judge bench (hearings from 15 April 2025); national GM crop policy directed but not yet finalised; commercial cultivation still stayed as of this note.

Hold the GM crops timeline loosely rather than as a fixed fact, since this is one of the few genuinely live regulatory questions on the syllabus.