Climate Change: UPSC Previous Year Questions (Environment and Ecology)
30 previous year UPSC Prelims questions on climate change appear here, from 2008 to 2025. The 2025 paper alone asked about cement emissions, COP28, Article 6, Direct Air Capture, per capita emissions and wet-bulb temperatures. UPSC also asks about carbon markets, geoengineering ideas and forest declarations. The explanations give the mechanism and the institution behind each.
Explanations state facts as of the year each question was asked; words like “recently” refer to that year.
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UPSC 2025Environment and Ecology · Climate Change
Q1. Consider the following statements: Statement I: Studies indicate that carbon dioxide emissions from cement industry account for more than 5% of global carbon emissions. Statement II: Silica-bearing clay is mixed with limestone while manufacturing cement. Statement III: Limestone is converted into lime during clinker production for cement manufacturing. Which one of the following is correct in respect of the above statements?
Explanation
Statement I is Correct: It is estimated that around 4-8 percent of the world’s carbon dioxide (CO₂) emissions come from the manufacture of cement, making it a major contributor to global warming
Statement II is correct but doesn’t explain statement I: Silica-bearing clay is mixed with limestone while manufacturing cement. Limestone, primarily composed of calcium carbonate (CaCO₃)₃), begins to decompose at temperatures around 825°C (1517°F). This process, called calcination, breaks down the limestone into calcium oxide (CaO) and carbon dioxide (CO₂). Thus the step of mixing Silica bearing clay and limestone contribute to the Carbon dioxide emission from cement industry.
Statement III is correct and explains Statement I: A significant portion of the emissions are an intrinsic part of the production of clinker. In the process of making cement clinker, limestone, which is primarily calcium carbonate (CaCO₃)₃), is heated to high temperatures (1450°C or 2640°F) in a kiln. This process, called calcination, decomposes the limestone into calcium oxide (CaO), commonly known as lime, and carbon dioxide (CO₂). The lime then reacts with other raw materials like clay and silica to form the clinker, which is the main ingredient in cement.
UPSC 2025Environment and Ecology · Climate Change
Q2. Consider the following statements: Statement I: At the 28th United Nations Climate Change Conference (COP28), India refrained from signing the ‘Declaration on Climate and Health’. Statement II: The COP28 Declaration on Climate and Health is a binding declaration; and if signed, it becomes mandatory to decarbonize health sector. Statement III: If India’s health sector is decarbonized, the resilience of its health-care system may be compromised. Which one of the following is correct in respect of the above statements?
Explanation
COP 28 was held in Dubai, UAE in December 2023. It introduced the COP28 Declaration on Climate and Health to reduce health sector greenhouse gas emissions, enhance climate-resilient health systems, and address climate-related health risks like air pollution and extreme weather. $1 billion was pledged by entities like the Rockefeller Foundation and Green Climate Fund for climate-health initiatives.
Statement I is correct: India abstained from signing due to concerns over reducing greenhouse gas emissions from cooling systems critical for healthcare infrastructure, especially in remote areas. Highlighted that cooling systems for vaccines and medicines ensure healthcare resilience, and decarbonization could disrupt service delivery. This aligned with India’s G20 presidency (2023) focus on resilient healthcare.
Statement II is incorrect: The COP28 Declaration is non-binding, encouraging voluntary actions like assessing health sector emissions, developing action plans, and promoting low-carbon health systems, active mobility, and sustainable diets. It operates outside UNFCCC/Paris Agreement frameworks, not mandating decarbonization. India raised concerns about cooling-related emissions feasibility, not mandatory requirements.
Statement III is correct: India argued that decarbonizing the health sector, particularly cooling systems for vaccine storage and hospitals, could compromise healthcare resilience in tropical climates and remote areas. A Kenyan delegate noted India’s concern that emission reductions could hinder medical demands in underserved regions. India’s G20 priorities (2023) emphasized healthcare access, medical countermeasures, and digital health platforms, supported by its low per-capita emissions (<4% of global GHG emissions) and developing nation status.
Exam tip:
For S2, UN Declarations (like COP outcomes) are typically non-binding. These are soft law instruments -- they express intent and global consensus but do not carry legal enforcement mechanisms. If a global declaration were legally binding, it would require parliamentary ratification, feature enforcement clauses, and likely cause wider international debate. Since none of that happened, the statement makes an extreme and unrealistic claim. Giving option C as correct.
UPSC 2025Environment and Ecology · Climate Change
Q3. Consider the following statements: Statement I: Article 6 of the Paris Agreement on climate change is frequently discussed in global discussions on sustainable development and climate change. Statement II: Article 6 of the Paris Agreement on climate change sets out the principles of carbon markets. Statement III: Article 6 of the Paris Agreement on climate change intends to promote inter-country non-market strategies to reach their climate targets. Which one of the following is correct in respect of the above statements?
Explanation
Article 6 of the Paris Agreement (2015, COP21) provides a framework for international cooperation to achieve climate goals through market-based and non-market-based mechanisms, enabling countries to meet their Nationally Determined Contributions (NDCs). It’s central to discussions on climate finance, GHG reduction, and SDG alignment.
Statement I is correct:
Article 6 is a cornerstone of the Paris Agreement, frequently discussed at COP summits--COP26 (Glasgow, 2021) and COP29 (Baku, 2024). It enables international cooperation for NDCs, addresses carbon markets and non-market approaches (NMAs), and mobilizes up to $1 trillion in climate finance by 2050. Highlighted by the World Bank and UNFCCC, it ensures environmental integrity and supports sustainable development. In India, with <4% of global GHG emissions, Article 6 is key in climate negotiations. Delays in rule finalization--e.g., COP25 (Madrid, 2019)--due to concerns like double counting underscore its importance.
Statement II is correct:
Article 6.2 allows bilateral trading of ITMOs with corresponding adjustments to avoid double counting. Article 6.4 sets up a UN-supervised Paris Agreement Crediting Mechanism (PACM), succeeding the Kyoto Protocol’s CDM, issuing A6.4ERs with 2% cancellation and 5% share for the Adaptation Fund. As per the World Bank and IISD, these rules--finalized at COP26 and advanced at COP29--enhance market integrity and climate finance. This explains Statement I, as carbon markets drive debates on market integrity, double counting, and private sector investment (e.g., $1 trillion potential by 2050).
Statement III is correct:
Article 6.8 promotes non-market approaches (NMAs) like tech transfers, policy coordination, and adaptation finance. Recognized by UNFCCC and Legal Response International, NMAs support equity, climate resilience, and SDGs, especially for nations like India, making Article 6 central in climate talks. This also explains Statement I, as NMAs address equity and cooperation, key topics in climate negotiations, especially for developing nations like India
UPSC 2025Environment and Ecology · Climate Change
Q4. With reference to Direct Air Capture’, an emerging technology, which of the following statements is/are correct? I. It can be used as a way of carbon sequestration. II. It can be a valuable approach for plastic production and in food processing. III. In aviation, it can be a source of carbon for combining with hydrogen to create synthetic low-carbon fuel. Select the correct answer using the code given below.
Explanation
Direct Air Capture (DAC) is an emerging negative emission technology that extracts carbon dioxide (CO₂) directly from the atmosphere. It is gaining attention for its potential to mitigate climate change by enabling carbon sequestration, utilization in products, and synthetic fuel production
Statement I is correct:
DAC uses chemical processes with liquid solvents (e.g., potassium hydroxide) or solid sorbents to extract CO₂ from the atmosphere. Captured CO₂ is sequestered in deep geological formations like saline aquifers or depleted oil/gas reservoirs for permanent storage, preventing atmospheric release. As of 2024, 27 DAC plants capture about 0.01 Mt CO₂/year, with plans for 130 facilities targeting 65 Mt CO₂/year by 2030 (IEA Net Zero Emissions scenario). DACCS is critical for carbon dioxide removal (CDR), essential to limit warming to 1.5°C (NASA, IPCC). Especially important for hard-to-abate sectors (e.g., aviation). India’s low per-capita emissions (<4% global GHG) make DACCS a strategic offset tool.
Statement II is correct:
CO₂ is a feedstock for industrial uses:
Plastics production (polycarbonates, polyurethanes) locks CO₂ for decades to centuries, offering durable sequestration. Food processing: carbonation of beverages, modified atmosphere packaging, with a global CO₂ market of 230 Mt/year. WRI highlights CO₂ use in plastics/concrete as more durable than short-term uses like beverages. DAC CO₂ use supports India’s food processing sector (Make in India focus). Despite costs ($400-740/tCO), policy support (e.g., US 45Q tax credits) enhances viability.
Statement III is correct:
DAC CO₂ combined with renewable hydrogen produces synthetic kerosene (power-to-liquid fuels) via processes like Fischer-Tropsch. SAFs are drop-in fuels compatible with existing aircraft, helping decarbonize aviation. DACCU mitigates CO₂ and non-CO₂ effects (contrails). Costs currently $1.50-4.50/gallon, expected to fall by 2050. India emits about 2% global aviation GHG, potentially benefiting from SAF adoption to meet CORSIA goals.
Additional insight:
DAC uses fans to pull air over sorbents/solvents; CO₂ is released with heat (~600°C). High energy use (6-10 GJ/tCO) is mitigated by renewable energy integration. Global DAC plants include Stratos (USA), Mammoth (Iceland), Kollsnes (Norway); India could deploy DAC in solar-rich states like Gujarat and Rajasthan. Key challenges: High costs, energy intensity; policy incentives like US 45Q tax credit ($20/tCO sequestration, $10/tCO enhanced oil recovery) and carbon markets drive adoption. India’s renewable energy push (450 GW target by 2030) and growing industrial sectors align with DAC for decarbonization.
Exam tip:
You can try, The "NOT" approach for all statements, this tests the improbability of negating a statement--if denying its impact seems highly unlikely, the statement is plausibly true. For example: Can DAC CO₂ be used in manufacturing? Yes --captured CO₂ is being tested in synthetic polymers, carbonated beverages, and even lab-grown food products. Denying its utility in these areas seems too rigid and ignores experimental applications. Similarly apply this in all three statements and observe that all are likely true.
UPSC 2025Environment and Ecology · Climate Change
Q5. Consider the following statements: I. Carbon dioxide (CO₂) emissions in India are less than 0.5 t CO₂/capita. II. In terms of CO₂ emissions from fuel combustion, India ranks second in Asia-Pacific region. III. Electricity and heat producers are the largest sources of CO₂ emissions in India. Which of the statements given above is/are correct?
Explanation
India, the third-largest global CO₂ emitter (2.8 Gt CO₂, 2023), has low per capita emissions (1.9-2.0 t CO₂/capita, 2022-2023) due to its 1.43 billion population (2022). Coal dominates power sector (75-76% electricity generation), followed by industry and transport.
Statement I is incorrect: Per capita CO₂ emissions measure annual emissions per person. IEA (2024) reports India’s at 2.0 t CO₂/capita (2023), Statista (2024) cites 1.89-2.0 t CO₂/capita (2022-2023), up from 1.79 t CO₂/capita (2021) due to economic growth and coal reliance. Our World in Data (2022) confirms 1.9 t CO₂/capita, below global average (4.6 t CO₂/capita) but above 0.5 t CO₂/capita. Worldometer (2022) notes 1.89 t CO₂/capita, historically 0.44 t (1980). Low emissions reflect large population and biomass use (13% lack electricity, Carbon Brief).
Statement II is correct: CO₂ emissions from fuel combustion (coal, oil, natural gas) reached 2.8 Gt CO₂ (2023, IEA), making India the second-largest emitter in Asia-Pacific after China (12.6 Gt CO₂). Emissions grew 7.2% (2023) due to coal-powered electricity (75% generation) and industrial growth (steel, cement).
Statement III is correct: Electricity and heat production, driven by coal-fired power plants (75% generation, 1,317 TWh, 2023, CEA Annual Report 2023-24), is India’s largest CO₂ source, contributing over 50% emission increase (1.4 Gt COe, Statista). Carbon intensity is 713 g CO₂/kWh, above global average (480 g CO₂/kWh). Industrial processes (cement, steel) and transport (oil-based) are secondary sources.
Exam tip:
The figure ‘less than 0.5 t CO₂/capita’ doesn’t align with India’s current scale of industrial activity, power consumption, and global rankings. Less than 0.5 tons is too low. Hence more probable to be false. Eliminating options A and D.
UPSC 2025Environment and Ecology · Climate Change
Q6. The World Bank warned that India could become one of the first places where wet-bulb temperatures routinely exceed 35°C. Which of the following statements best reflect(s) the implication of the above-said report? I. Peninsular India will most likely suffer from flooding, tropical cyclones and droughts. II. The survival of animals including humans will be affected as shedding of their body heat through perspiration becomes difficult. Select the correct answer using the code given below.
Explanation
Wet-bulb temperature is the lowest temperature that air can reach through the process of evaporation of water under current atmospheric conditions. It is measured by wrapping a thermometer bulb in a wet cloth and exposing it to air flow; as water evaporates from the cloth, it cools the thermometer, and the resulting temperature is the wet-bulb temperature.
Statement 1 is incorrect: Flooding, tropical cyclones and droughts in the Peninsular India are significant impacts of climate change. These are not the direct implications of the wet-bulb temperatures exceeding 35°C. The World Bank’s warning in its report titled Climate Investment Opportunities in India’s Cooling Sector, specifically relates to heat and humidity, not to hydrometeorological events like floods or cyclones.
Statement 2 is correct: This statement directly reflects the core implication of the World Bank’s report titled "Climate Investment Opportunities in India’s Cooling Sector". At wet-bulb temperatures above 35°C, humans and animals cannot cool themselves through sweating, leading to life-threatening conditions.
Additional insight:
Wet-bulb temperature reflects both heat and humidity in the air. When relative humidity is high, less evaporation occurs, so the wet-bulb temperature is closer to the actual air temperature. When humidity is low, more evaporation happens, making the wet-bulb temperature much lower than the air temperature. At 100% relative humidity, the wet-bulb and air temperatures are equal because no more evaporation can occur. Wet-bulb temperature is important because it indicates the limit at which humans and animals can cool themselves by sweating. If the wet-bulb temperature rises above 35°C, the body can no longer shed heat effectively, making survival difficult even for healthy individuals.
UPSC 2023Environment and Ecology · Climate Change
Q7. Consider the following statements: Statement-I: Carbon markets are likely to be one of the most widespread tools in the fight against climate change. Statement-II: Carbon markets transfer resources from the private sector to the State. Which one of the following is correct in respect of the above statements?
Explanation
Statement I is correct: Carbon markets are trading systems in which carbon credits are sold and bought. Companies or individuals can use carbon markets to compensate for their greenhouse gas emissions by purchasing carbon credits from entities that remove or reduce greenhouse gas emissions. One tradable carbon credit equals one tonne of carbon dioxide or the equivalent amount of a different greenhouse gas reduced, sequestered or avoided. Carbon markets, including compliance and voluntary markets, are widely recognized as effective tools for reducing greenhouse gas emissions. They incentivize emission reductions by allowing entities to trade carbon credits, making them a key mechanism in global climate action.
Statement II is correct: Carbon markets help reduce green-house gas emissions by assigning value to carbon and creating a market for trading carbon credits, which represent the right to emit a certain amount of greenhouse gases. They enable more efficient allocation of emission reduction efforts and facilitate the exchange of allowances between public and private entities, of-ten involving financial transactions. Carbon markets can generate revenue for governments through mechanisms like the sale of emission allowances in compliance markets. However, this is not their primary purpose, as carbon markets primarily facilitate trading between private entities to reduce emissions efficiently.
UPSC 2022Environment and Ecology · Climate Change
Q8. Consider the following statements: 1. "The Climate Group" is an international non-profit organization that drives climate action by building large networks and runs them. 2. The International Energy Agency in partnership with the Climate Group launched a global initiative "EP100". 3. EP100 brings together leading companies committed to driving innovation in energy efficiency and increasing competitiveness while delivering on emission reduction goals. 4. Some Indian companies are members of EP100. 5. The International Energy Agency is the Secretariat to the ’Under2 Coalition’. Which of the statements given above are correct?
Explanation
Statement 1 is correct: The Climate Group is an inter-national non-profit organization that works to accelerate climate action by building and running large networks of businesses, governments, and other organizations. It focuses on initiatives like RE100 (renewable energy), EP100 (energy productivity), and EV100 (electric vehicles).
Statement 2 is incorrect: The EP100 initiative is led by the Climate Group in partnership with the Alliance to Save Energy, not the International Energy Agency (IEA).
Statement 3 is correct: EP100 is a global initiative that encourages companies to commit to doubling their energy productivity (output per unit of energy consumed). This helps drive innovation, increase competitiveness, and reduce greenhouse gas emissions.
Statement 4 is correct: Several Indian companies, such as Mahindra & Mahindra, Godrej and Dalmia Cement, are members of EP100 and have committed to improving their energy productivity.
Statement 5 is incorrect: EP100 is a global initiative that brings together companies committed to improving energy productivity. The Under2 Coalition is a global alliance of state and regional governments committed to reducing greenhouse gas emissions. Its Secretariat is managed by Climate Group.
Exam tip:
You can try, The "NOT" approach for all statements, this tests the improbability of negating a statement--if denying its impact seems highly unlikely, the statement is plausibly true. For Example: CO₂ or O₃ are NOT released in crop burning? Absurd, unlikely.
UPSC 2022Environment and Ecology · Climate Change
Q9. "Climate Action Tracker" which monitors the emission reduction pledges of different countries is a:
Explanation
Option (a) is correct: The Climate Action Tracker (CAT) is an independent scientific project that monitors government climate action and measures it against the globally agreed Paris Agreement aim of "holding warming well below 2°C, and pursuing efforts to limit warming to 1.5°C." It is a collaboration between Climate Analytics and the New Climate Institute. CAT has been providing assessments since 2009. It evaluates countries’ emission reduction pledges, policies, and their impact on global warming. Options (b), (c) and (d) are incorrect:
The Climate Action Tracker is neither a part of the Intergovernmental Panel on Climate Change (IPCC) nor the UNFCCC. The IPCC is a separate body that assesses scientific, technical, and socio-economic information related to climate change. The UNFCCC is an international treaty that provides the framework for global climate negotiations. The Climate Action Tracker is not funded or promoted by the United Nations Environment Programme (UNEP) or the World Bank. It is an independent initiative run by research organizations.
UPSC 2021Environment and Ecology · Climate Change
Q10. With reference to the ‘New York Declaration on Forests’, which of the following statements are correct? 1. It was first endorsed at the United Nations Climate Summit in 2014. 2. It endorses a global timeline to end the loss of forests. 3. It is a legally binding international declaration. 4. It is endorsed by governments, big companies and indigenous communities. 5. India was one of the signatories at its inception. Select the correct answer using the code given below.
Explanation
Statement 1 is correct: The NYDF was launched and endorsed at the United Nations Climate Summit in New York on September 23, 2014. It was a significant global effort to address deforestation and promote forest conservation.
Statement 2 is correct: The NYDF sets a global timeline to end natural forest loss by 2030 and to restore 350 million hectares of degraded forest and agricultural land by the same year. It also aims to halve deforestation by 2020 (though this target was not met).
Statement 3 is incorrect: The New York Declaration on Forests (NYDF) is a voluntary and non-legally binding international declaration aimed at ending global deforestation.
Statement 4 is correct: The NYDF has been endorsed by a wide range of stakeholders, including national governments, multinational companies, NGOs, and indigenous communities. Over 200 entities have pledged their support.
Statement 5 is incorrect: India was not a signatory to the NYDF at its inception. While many countries, including the United States, Canada, and several European nations, endorsed the declaration, India has still not joined as a signatory.
Exam tip:
For S3, since when declarations become legally binding? Aren’t treaties there for that? Legally binding is strong requirement, seldom international declaration are legally binding, hence more likely false. Eliminating options B and C. Now as compare to S5(much more specific and hence easy to manipulate) S2 is much more general and practical to be false.
Answer key for these questions
Q
UPSC year
Correct answer
1
2025
(b) Both Statement II and Statement III are correct but only one of them explains Statement I
2
2025
(c) Only one of the Statements II and III is correct and that explains Statement I
3
2025
(a) Both Statement II and Statement III are correct and both of them explain Statement I
4
2025
(c) I, II and II
5
2025
(c) II and III only
6
2025
(b) II only
7
2023
(b) Both Statement-I and Statement-II are correct and Statement-II is not the correct explanation for Statement-I
8
2022
(b) 1, 3 and 4 only
9
2022
(a) Database created by coalition of research organisations
10
2021
(a) 1, 2 and 4
What UPSC has tested in Climate Change
Article 6 of the Paris Agreement deals with carbon markets and cooperative approaches between countries.
Direct Air Capture extracts carbon dioxide directly from the atmosphere and can be used for carbon sequestration.
Cirrus cloud thinning is suggested by some scientists as a way of reducing the global warming.
Climate Action Tracker is a database created by climate research organisations that monitors countries’ emission pledges.
The World Bank has warned that India could become one of the first places where wet-bulb temperatures exceed human tolerance.
Frequently asked questions
How many previous year UPSC questions are there on Climate Change?
This page covers 30 previous year UPSC Prelims GS Paper-I questions on Climate Change (Environment and Ecology), asked from 2008 to 2025. Each has the correct answer and an explanation.
What does Article 6 of the Paris Agreement cover?
Voluntary cooperation between countries to meet their climate targets, including carbon markets in which emission reductions can be traded and used toward national contributions, along with non-market approaches.
What is Direct Air Capture?
A technology that removes carbon dioxide directly from the ambient air using chemical solvents or solid sorbents. The captured carbon can be stored underground or used in fuels and products, so it can help cut atmospheric carbon.
What is a wet-bulb temperature?
A measure that combines heat and humidity. When the wet-bulb temperature approaches 35 °C, the human body can no longer cool itself by sweating, so even healthy people can die within hours without relief.
