Climate change — greenhouse effect, global warming & impacts

Climate change in UPSC is not a single science fact; it is the meeting point of atmospheric physics, ecology, law, economics and global equity.

• Climate change: a long-term shift in temperature, rainfall, wind, ocean conditions and extreme events. It may arise naturally, but present warming is mainly human-driven.
• Weather vs climate: weather is short-term atmospheric condition; climate is the long-term pattern normally assessed over about 30 years. A cold week does not disprove long-term warming.
• Greenhouse effect: incoming short-wave solar radiation largely passes through the atmosphere; Earth emits long-wave infrared radiation; greenhouse gases absorb and re-emit part of it, keeping the lower atmosphere warm.
• Enhanced greenhouse effect: human activities add extra greenhouse gases and disturb carbon, nitrogen and water cycles. The natural blanket becomes thicker, so less heat escapes to space.
• Global warming: the rise in global mean surface temperature. IPCC AR6 states that human activities have unequivocally caused warming, with 2011-2020 about 1.1°C above 1850-1900.
• Climate change is wider than warming: it includes heatwaves, intense rainfall, drought, cyclones, glacier retreat, ocean warming, sea-level rise, acidification, crop stress, disease range shifts and biodiversity disruption.
• Constitutional basis in India: Article 21 supports the right to life and a clean environment; Article 14 matters because climate harms fall unequally; Article 48A directs the State to protect the environment; Article 51A(g) makes environmental protection a citizen duty.
• Legal basis: the Environment Protection Act, 1986 gives broad central powers after the Bhopal disaster; the Air Act, 1981 and Water Act, 1974 regulate pollution; the Forest Conservation Act, 1980 and Wildlife Protection Act, 1972 protect carbon sinks and habitats; the National Green Tribunal Act, 2010 creates a specialist forum.
• Prelims trap: the Constitution does not contain a separate climate-change article. Climate protection is read through existing rights, duties, directive principles and environmental statutes.
• Scope limitation: climate law in India is still dispersed. India has climate policy, missions and commitments, but no single umbrella climate-change statute comparable to an all-in-one climate code.
• Terms under the Environment Protection Act: climate change is not named as a separate offence in the Act, but the Act’s broad definitions of environment, environmental pollutant and environmental pollution allow regulation of activities that degrade air, water, land and ecological systems. Rules on waste, coastal zones, environmental clearance and industrial standards are therefore indirectly climate-relevant.
• Schedules and lists: the constitutional Seventh Schedule distributes subjects such as forests, protection of wild animals and birds, electricity, water, agriculture and public health across Union, State and Concurrent responsibilities. Climate action therefore needs cooperative federalism rather than one central command.
• International law status: treaty commitments normally need domestic implementation through law, policy or executive action. A UPSC statement saying that every Paris pledge is directly enforceable in an Indian court should be treated cautiously.