Airlines and CORSIA
Aviation emits about 2–3% of global CO₂. Airlines report fuel burn per flight and convert it at 3.16 kg CO₂ per kg of jet fuel, then divide by passengers and cargo to give per-seat footprints shown at booking.
The ICAO CORSIA scheme requires airlines on international routes to offset growth above a baseline (85% of 2019 emissions from 2024) with approved credits, or cut emissions with sustainable aviation fuel (SAF). Book-and-claim systems let a buyer claim SAF used elsewhere in the network. Non-CO₂ effects such as contrails roughly double aviation's warming impact, which some calculators include as a multiplier.
A short history
- 1992 — Rio Earth Summit creates the UN climate convention (UNFCCC).
- 1997 — Kyoto Protocol sets binding targets for rich countries and creates the Clean Development Mechanism (CDM), under which many Indian hydro and wind projects earned credits.
- 2005 — EU Emissions Trading System launches, the world's first major carbon market.
- 2015 — Paris Agreement; Article 6 allows countries to trade emission reductions.
- 2016 — ICAO adopts CORSIA for aviation.
- 2023–24 — India launches CCTS; EU CSRD and the SEC climate rule bring mandatory corporate carbon reporting.