Scientists have published a fresh set of global emission pathways that will underpin climate research and the upcoming IPCC assessment. The notorious high‑emission case RCP8.5, once the benchmark for worst‑case warming, has been officially retired after 15 years.
Key Developments
- Retirement of RCP8.5: The scenario is deemed implausible because renewable energy has expanded rapidly and major economies are peaking or reducing emissions.
- New highest pathway: The latest suite projects a warming of about 3.5 °C by 2100, lower than the earlier 5 °C estimate linked to RCP8.5.
- No feasible 1.5 °C pathway: Even the most optimistic new scenarios require temporary overshoot of the 1.5 °C limit under current policies.
- Paris Agreement goals at risk: Achieving the agreement’s temperature ceiling without overshoot is impossible unless emissions fall far faster than today.
Important Facts
The seven scenarios were produced by a global consortium of earth‑system modelers and released in April 2026. They replace the older SSP5‑8.5 pathway that projected about 4.4 °C warming. The shift reflects three trends: (i) a swift transition to renewables in China, the world’s top emitter; (ii) peaking and declining emissions in the United States and Europe; (iii) plateauing emissions in China.
These scenarios feed into the CMIP7 model suite, which underpins the next IPCC report. They are used to simulate temperature rise, rainfall changes, sea‑level rise, glacier melt and other impacts.
UPSC Relevance
Understanding these pathways is vital for GS3 – Environment and Climate Change. The retirement of RCP8.5 shows how scientific assessments evolve with policy and technology, a point often asked in essay and answer‑writing questions. The continued risk of >2 °C warming highlights the need to study India’s exposure to extreme events, a frequent topic in case‑study based questions. Moreover, the