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Climate change in UPSC Prelims is no longer a question about the greenhouse effect. In Tootler's bank of transcribed papers, 31 General Studies questions between 2008 and 2026 deal with climate change, spread across 16 different exam years. The early ones asked which gases warm the atmosphere. The recent ones ask what direct air capture is used for, whether carbon markets move money to the State, and what India's 2024 emissions report recorded.
That shift is the reason to study this topic by concept rather than by news item. This guide groups all 31 questions into four areas, explains the concept behind each using the definitions in the IPCC's own glossary, and shows the question UPSC built on it.
Source: Tootler's transcription of UPSC Prelims question papers.
This guide is part of Tootler's series on environment and ecology for UPSC, which maps all 284 environment questions in Prelims by topic.
Greenhouse gases: where they come from and how strongly they warm
The oldest questions in this set test sources and strength. In 2008, UPSC asked which of four activities release methane. The IPCC glossary covers most of the options: methane is the main component of natural gas and "associated with all hydrocarbon fuels", significant human emissions come from animal husbandry and paddy rice, and it is produced naturally wherever organic matter decays without oxygen, "such as in wetlands".
Consider the following : 1. Rice fields 2. Coal mining 3. Domestic animals 4. Wetlands
Which of the above are sources of methane, a major greenhouse gas?
Strength is measured by global warming potential, which the IPCC defines as the warming effect of a unit mass of a gas over a chosen time horizon, relative to carbon dioxide. It combines how long a gas stays in the atmosphere with how effectively it traps heat. That idea sits behind the 2010 question that listed soot, sulphur hexafluoride and water vapour. Soot, or black carbon, is a useful one to know precisely: the IPCC describes it as a product of incomplete combustion that stays in the atmosphere only for days or weeks yet has a strong warming effect, both in the air and when it settles on snow or ice.
Two other questions in this group are really about ozone. The 2011 question on the Antarctic ozone hole and the 2012 question on the uses of chlorofluorocarbons belong to the ozone-layer story under the Montreal Protocol. The link to climate came later: the Kigali Amendment of 2016 brought hydrofluorocarbons under the same protocol. UPSC asked about the uses of hydrofluorocarbons in 2023.
The impact questions round this area off: what ocean acidification does to corals and plankton (2012), what a rise of more than 3°C could do to the biosphere (2014), and what "carbon fertilization" means (2018). Each tests whether you can separate a real, documented effect from an exaggerated one in the options.
Carbon sinks and carbon removal: the fastest-growing area
Seven questions deal with taking carbon out of the air or keeping it out, and six of them are from 2017 onwards. This is where Prelims has moved fastest, so the vocabulary matters.
The IPCC calls the basic process sequestration, "the process of storing carbon in a carbon pool", and uses carbon dioxide removal for human activities that take CO2 from the atmosphere and store it durably in geological, land, ocean or product reservoirs. Carbon capture and storage at a factory or power plant is not removal on its own; it only becomes removal when combined with bioenergy or with capture from the air.
| Concept | What it means (IPCC) | Asked in |
|---|---|---|
| Soil carbon sequestration | Land management changes that raise soil organic carbon | 2012 |
| Solar radiation modification | Methods that limit warming by reducing incoming sunlight or changing cloud properties, not by cutting emissions | 2019 |
| Blue carbon | Carbon stored by marine systems, mainly mangroves, tidal marshes and seagrasses | 2021 |
| Enhanced weathering | Grinding silicate or carbonate rocks and spreading them on soil, beaches or the ocean to speed up natural CO2 removal | 2023 |
| Direct air capture | Chemically capturing CO2 directly from ambient air, followed by storage | 2025 |
The 2017 question, on which underground formations could store CO2, and the 2024 question on the world's largest tropical peatland test the same idea from the storage end.
The 2023 question is a good test of whether you know these terms or only recognise them. Spreading ground basalt on farmland is enhanced weathering; adding lime to the sea is ocean alkalinity enhancement, which the IPCC lists among removal methods:
Consider the following activities : 1. Spreading finely ground basalt rock on farmlands extensively 2. Increasing the alkalinity of oceans by adding lime 3. Capturing carbon dioxide released by various industries and pumping it into abandoned subterranean mines in the form of carbonated waters How many of the above activities are often considered and discussed for carbon capture and sequestration?
Show answer
(c) All three
From a third-party answer key, not yet checked against UPSC's official key.
Blue carbon is worth knowing exactly as the IPCC phrases it, because the 2021 options offered forests, fossil fuels and the atmosphere as distractors:
What is blue carbon?
Show answer
(a) Carbon captured by oceans and coastal ecosystems
From a third-party answer key, not yet checked against UPSC's official key.
The 2019 question on cirrus cloud thinning and sulphate aerosols belongs here too. Both are forms of solar radiation modification, which the IPCC describes as measures "not related to greenhouse gas mitigation that seek to limit global warming". They work on sunlight, not on carbon.
Carbon accounting and carbon markets
Five questions ask how emissions are measured and priced. They tend to be definitional, with options that sound similar.
The Greenhouse Gas Protocol (asked in 2016) is a set of standards, guidance and tools for businesses and governments to measure and manage their emissions, not a treaty with targets. The carbon price, in the IPCC's words, is the price for avoided or released CO2, which "may refer to the rate of a carbon tax, or the price of emission permits". Carbon markets, asked as a pair of statements in 2023, are the permit side of that definition. The social cost of carbon (2020) is the net present value of the climate damage caused by one more tonne of carbon, a money measure of harm rather than of fuel use or personal footprint:
Which one of the following statements best describes the term 'Social Cost of Carbon'? It is a measure, in monetary value, of the
Show answer
(a) long-term damage done by a tonne of CO2 emissions in a given year.
From a third-party answer key, not yet checked against UPSC's official key.
India now has its own version. A 2022 amendment to the Energy Conservation Act gave the legal basis for the Carbon Credit Trading Scheme, notified in June 2023, with the Bureau of Energy Efficiency as administrator. Its compliance side is an intensity-based baseline-and-credit system: covered industries in eight energy-intensive sectors earn tradeable carbon credit certificates, each worth one tonne of CO2-equivalent, when they beat their emissions-intensity targets, and must surrender units when they miss them. Knowing that design helps with statement questions like the 2023 one, which turn on who pays whom in a carbon market.
Two other questions in this group, on the UNEP-supported Common Carbon Metric (2021) and the Greendex survey (2010), show the same pattern: UPSC picks a named index from the news and asks what it measures.
India's climate policy
Policy questions have appeared regularly since 2016, including both climate questions in the 2026 paper. Two documents and one forest framework cover most of them.
The National Action Plan on Climate Change, released on 30 June 2008, is built on eight national missions. UPSC has asked about two of them: the National Water Mission (2012) and the Green India Mission (2016), which the government describes as responding to climate change "by a combination of adaptation and mitigation measures".
Which of the following best describes/describe the aim of 'Green India Mission' of the Government of India? 1. Incorporating environmental benefits and costs into the Union and State Budgets thereby implementing the 'green accounting'. 2. Launching the second green revolution to enhance agricultural output so as to ensure food security to one and all in the future. 3. Restoring and enhancing forest cover and responding to climate change by a combination of adaptation and mitigation measures. Select the correct answer using the code given below.
Show answer
(c) 3 only
From a third-party answer key, not yet checked against UPSC's official key.
India's Long-Term Low Emission Development Strategy, submitted to the UNFCCC in 2022, sets out the path to net-zero emissions by 2070 and notes that India updated its nationally determined contribution in August 2022. The 2026 paper tested this strategy alongside India's fourth Biennial Update Report:
Consider the following statements with reference to India’s response to climate change :
I. India’s Long-Term Low Emission Development Strategy (LT-LEDS) is a crucial tool for achieving net-zero emissions by 2070.
II. India’s 4th Biennial Update Report (BUR-4) submitted in December, 2024 recorded around 8% decrease in Greenhouse gas emissions in 2020 over 2019.
III. Climate-resilient development necessarily depends on quick and short-term achievement of emission reduction targets.
Which of the following relationships among the above statements is/are correct ?
1. Statement I is empirically supported by statement II.
2. Statement III contradicts the approach implicit in statement I.
3. Statement I and statement III together establish the premise of long-term sustainability.
Select the answer using the code given below :
Forests connect the two documents. REDD+, the framework for reducing emissions from deforestation and forest degradation, appeared in 2016 and again in 2026, the second time asking which Indian project was first certified under it.
How to prepare climate change for Prelims
Treat this topic as vocabulary plus a short list of documents. Learn the IPCC definitions of the removal and accounting terms above until you can tell enhanced weathering from ocean alkalinity enhancement and a carbon price from the social cost of carbon. Then read the NAPCC missions and India's long-term strategy once, slowly, and note the numbers and dates in them.
News items will keep changing, but they almost always hang on one of these concepts. When a new term appears in your current affairs reading, ask which of the four areas it belongs to and file it there. That is how the questions above were built.
Frequently asked questions
How many questions on climate change has UPSC Prelims asked?
In Tootler's bank of transcribed papers, 31 General Studies questions from 2008 to 2026 deal with climate change, spread over 16 different exam years. The topic is rising: 2023 to 2026 alone account for nine of them, mostly on carbon removal, carbon markets and India's climate policy.
What is blue carbon?
The IPCC defines blue carbon as biologically driven carbon fluxes and storage in marine systems that are amenable to management. Coastal blue carbon refers to mangroves, tidal marshes and seagrasses, which bury carbon quickly in their soils and sediments and release most of it if they are degraded or lost.
What is the difference between carbon capture and storage and carbon dioxide removal?
Carbon dioxide removal takes CO2 out of the atmosphere and stores it durably, for example through forests, enhanced weathering or direct air capture. Carbon capture and storage on its own only stops CO2 from an industrial or energy source reaching the air; the IPCC notes it removes CO2 only when combined with bioenergy or direct air capture.
When does India aim to reach net zero?
India's Long-Term Low Emission Development Strategy, submitted to the UNFCCC in 2022, sets out a path to net-zero emissions by 2070. The same document notes that India updated its nationally determined contribution in August 2022 to reflect the targets announced at Glasgow.
What are the missions under India's National Action Plan on Climate Change?
The National Action Plan on Climate Change, released on 30 June 2008, has eight missions: Solar, Enhanced Energy Efficiency, Sustainable Habitat, Water, Sustaining the Himalayan Ecosystem, Green India, Sustainable Agriculture, and Strategic Knowledge for Climate Change. UPSC has asked about the Green India and Water missions.