IPCC

1. Mandate and place in climate governance

The IPCC assesses the state of knowledge on climate change through comprehensive reviews of scientific, technical and socioeconomic literature. Its central questions concern the causes of warming, observed and projected consequences, and options for adaptation and mitigation. It evaluates evidence rather than generating new experimental findings. Thousands of experts contribute as authors and reviewers, generally without remuneration from the IPCC.

Its assessments are policy-relevant but not policy-prescriptive. They may compare the consequences, costs and feasibility of alternative pathways, but do not instruct governments to adopt a particular tax, energy technology or development model. This distinction allows scientific findings to inform choices while leaving political decisions to governments.

The IPCC is not a treaty body of the United Nations Framework Convention on Climate Change. The UNFCCC, adopted in 1992, provides the negotiating framework within which the Kyoto Protocol and Paris Agreement were adopted. IPCC assessments supply scientific inputs to those negotiations. India participates in the IPCC as a member government, and Indian researchers contribute across its reports.

• IPCC: assesses climate science and response options.
• UNFCCC and its governing bodies: organise negotiations and oversee implementation of climate agreements.
• WMO: supports international cooperation in meteorology, climatology and related observations.
• UNEP: coordinates and supports the wider environmental agenda within the United Nations system.

2. Organisation and assessment products

The Panel, consisting of representatives of member governments, takes major decisions in plenary sessions, including report outlines and the election of the Bureau. The Bureau provides scientific and technical guidance. Working Groups and the inventory Task Force are supported by Technical Support Units, while the Secretariat facilitates the overall assessment process.

Working Group I assesses the physical science basis: greenhouse gases, radiative forcing, observations, modelling, attribution and projections. Working Group II assesses impacts, adaptation and vulnerability across ecosystems, settlements and economic sectors. Working Group III evaluates mitigation, including energy systems, transport, land use, industry, demand-side measures and policy instruments.

Assessment Reports bring together the Working Group contributions and a Synthesis Report integrating their findings. Special Reports examine focused themes. Important examples include Global Warming of 1.5°C in 2018, and the 2019 reports on Climate Change and Land and The Ocean and Cryosphere in a Changing Climate.

Methodology Reports support greenhouse gas accounting. The 2006 IPCC Guidelines for National Greenhouse Gas Inventories, supplemented by the 2019 Refinement, provide methods for estimating emissions and removals. These methodologies underpin national inventories; they are not rankings of countries’ climate performance.

3. How reports are prepared and uncertainty is expressed

An assessment begins with scoping and governmental agreement on an outline. Governments and observer organisations nominate experts; the Bureau selects authors with attention to expertise and geographical and gender balance. Author teams assess published evidence, while review editors help ensure that substantive review comments receive appropriate consideration.

Drafts undergo expert review and government review at specified stages. The IPCC primarily assesses peer-reviewed research but can also use other literature, subject to procedures for evaluating its quality and validity. Thus, the statement that it uses only peer-reviewed journal articles is incorrect.

Summaries for Policymakers undergo line-by-line approval by governments in dialogue with authors. Approval must remain consistent with the underlying scientific assessment. The full Working Group reports are accepted rather than negotiated line by line. Government participation gives the summaries intergovernmental standing without converting them into legally binding commitments.

Calibrated language distinguishes confidence from likelihood. Confidence reflects the strength of evidence and degree of agreement, expressed from very low to very high. Likelihood expresses an assessed probability: likely means 66–100%, very likely 90–100%, and virtually certain 99–100%. A statement of high confidence is therefore not automatically a numerical probability.

4. Major findings of the Sixth Assessment Report

The Sixth Assessment Report concluded that human activities, principally greenhouse gas emissions, have unequivocally caused global warming. Global surface temperature in 2011–2020 was approximately 1.1°C above the 1850–1900 baseline. This is a multi-year assessment, not the anomaly of a particular recent year.

Every increment of warming intensifies multiple and concurrent hazards. Human-caused climate change already affects weather and climate extremes across regions, including hot extremes and heavy precipitation. Around 3.3–3.6 billion people live in contexts highly vulnerable to climate change. Vulnerability is shaped by inequality, poverty, weak governance and inadequate access to services, not merely physical exposure.

Limiting human-caused warming requires net-zero carbon dioxide emissions alongside strong reductions in other greenhouse gases. In modelled pathways limiting warming to 1.5°C with no or limited overshoot, global greenhouse gas emissions fall by about 43% by 2030 from 2019 levels. This is a global pathway finding, not an identical reduction obligation for every country.

Adaptation becomes less effective as warming increases, and some systems already face adaptation limits. Climate-resilient development integrates adaptation and mitigation with sustainable development. Overshooting a warming level may create irreversible impacts even if temperatures subsequently decline through sustained net-negative carbon dioxide emissions.

5. Relevance for India and examination distinctions

For India, IPCC findings inform analysis of heat stress, monsoon variability, intense rainfall, Himalayan cryosphere changes, coastal risks and agricultural vulnerability. These interacting hazards require regional assessments: a global projection cannot be mechanically applied to a particular district. Exposure, infrastructure and socioeconomic vulnerability determine how hazards translate into losses.

IPCC evidence can support implementation of the National Action Plan on Climate Change, State Action Plans, resilient infrastructure and coastal planning. It also informs debates on equity, historical emissions, development needs and finance. However, India’s nationally determined contribution and long-term strategy are governmental submissions under the Paris Agreement, not targets assigned by the IPCC.

A carbon budget is the estimated cumulative net carbon dioxide emissions compatible with a temperature limit at a specified probability, subject to assumptions about non-CO2 warming and Earth-system responses. Allocating that budget among countries involves ethical and political judgements. Similarly, a scenario describes a conditional future; it is not a forecast that must occur.

• Mitigation addresses emissions and sinks; adaptation addresses actual or expected climate impacts.
• Net-zero CO2 and net-zero greenhouse gases are distinct concepts.
• A single year above 1.5°C does not by itself establish that the Paris Agreement’s long-term temperature threshold has been crossed.
• IPCC findings inform the Paris Agreement’s Global Stocktake but do not themselves constitute its negotiated outcome.

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