Overview
- A multi‑author modeling paper published this spring concludes the extreme RCP8.5 (SSP5‑8.5) pathway is now implausible because renewable costs, deployment and recent emission trends changed realistic energy trajectories.
- The revised scenario set lowers the top‑end projection to about 3.5°C of warming by 2100 while the best‑case path now temporarily exceeds the Paris 1.5°C goal, peaking near 1.7°C unless large‑scale carbon removal is deployed.
- Scientists emphasize that dropping the extreme pathway reduces the most apocalyptic outcomes but does not remove major risks from warming, climate feedbacks or rising sea levels and extreme weather.
- The change has immediate policy and research consequences because thousands of studies, regulations and infrastructure plans treated RCP8.5 as a baseline and will need reassessment while extreme scenarios remain for low‑probability risk planning.
- Political and media actors have framed the revision variably—from presidential celebration to claims of overstated alarmism—prompting scientists to clarify that the update reflects progress in energy trends, not the end of climate harms.