climate change

Climate change denotes the long‑term alteration of Earth’s average temperature and the statistical distribution of weather events, driven primarily by anthropogenic greenhouse‑gas emissions. Its significance lies in the cascading impacts on cryospheric melt, sea‑level rise, biodiversity loss, and human systems ranging from agriculture to urban infrastructure, making it a defining challenge of the 21st century. ## Scientific Basis and Mechanisms The greenhouse effect, first quantified by Svante Arrhenius in 1896, explains how gases such as carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O) trap infrared radiation. Atmospheric CO₂ concentrations rose from 280 ppm in pre‑industrial times to 421 ppm in 2023, a 50 % increase documented by the Mauna Loa Observatory. This rise correlates with a global mean surface temperature increase of 1.1 °C above the 1850‑1900 baseline, as reported in the IPCC Sixth Assessment Report (AR6, 2021). Oceanic heat uptake accounts for roughly 90 % of excess energy, leading to a measured sea‑level rise of 3.3 mm yr⁻¹ since 1993, according to satellite altimetry. Simultaneously, Arctic sea‑ice extent has contracted by about 13 % per decade since 1979, amplifying albedo feedbacks. The combined effect of thermal expansion, glacial melt, and ice‑sheet dynamics threatens low‑lying coastal megacities such as Mumbai and New York with inundation by the end of the century under high‑emission scenarios. ## Historical Development of the Concept The term “climate change” entered scientific parlance in the early 1970s, but the first international policy response emerged with the United Nations Framework Convention on Climate Change (UNFCCC) in 1992, signed by 154 states at the Earth Summit in Rio de Janeiro. The 1997 Kyoto Protocol introduced legally binding emission caps for 37 industrialised countries, targeting a collective 5 % reduction relative to 1990 levels by 2012. After the Kyoto commitment period lapsed, the 2015 Paris Agreement established a bottom‑up architecture of Nationally Determined Contributions (NDCs), aiming to limit warming to well below 2 °C and pursue 1.5 °C. Subsequent IPCC assessment cycles—most notably the 2014 Fifth Assessment Report (AR5) and the 2021 AR6—provided increasingly granular attribution studies, confirming that human influence accounts for >99 % of observed warming since 1950. These scientific milestones have spurred a proliferation of climate‑finance mechanisms, including the Green Climate Fund (established 2010) which disbursed US$10.3 billion to developing nations by 2022. ## Global Governance and Agreements The Paris Agreement’s “global stocktake” scheduled for 2023 evaluated collective progress and reaffirmed the need for net‑zero emissions by mid‑century. As of 2024, 195 parties have submitted updated NDCs, with the European Union pledging a 55 % emissions cut by 2030 relative to 1990 levels. The United Nations Climate Change Conference (COP28) in Dubai 2023 introduced a “loss and damage” fund, earmarked for vulnerable nations facing irreversible impacts such as small‑island states. India and Norway exemplified bilateral climate diplomacy in 2023 by upgrading their cooperation to a “Green Strategic Partnership,” committing US$1.5 billion toward renewable‑energy projects, hydrogen research, and forest‑carbon initiatives. The partnership aligns with Norway’s 2022 climate‑action plan, which targets a 55 % reduction in domestic emissions by 2030, and underscores the role of high‑income nations in supporting emerging economies. ## India's Climate Policy Landscape India’s National Action Plan on Climate Change (NAPCC), launched in 2008, comprises eight missions ranging from solar energy to sustainable agriculture. The country’s NDC, submitted in 2021, pledges a 40 % reduction in emissions intensity (grams CO₂ per kWh of GDP) by 2030 and an increase in renewable‑energy capacity to 450 GW by the same year. By 2022, solar installations reached 58 GW, accounting for 12 % of total electricity generation, while wind capacity stood at 39 GW. In response to extreme heatwaves and flood events, Delhi initiated a month‑long fire‑safety compliance drive in 2024 after the Malviya Nagar tragedy, integrating climate‑resilience standards into building codes. Simultaneously, the Ministry of Environment, Forest and Climate Change (MoEFCC) launched an AI‑driven early‑warning platform in 2023 that reduced flood‑prediction lead times by 30 % across the Ganges basin, illustrating the convergence of technology and policy. ## Technological and Societal Responses Renewable‑energy technologies have scaled rapidly: global solar‑photovoltaic capacity grew from 40 GW in 2010 to 940 GW in 2023, according to the International Renewable Energy Agency (IRENA). Battery storage, exemplified by the 2 GWh