{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"9b774aa0fa47b22839c23e6b4686611ac1a806fd1607db52106029c5077cda20","created":"2026-10-03T07:18:02Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"f3ca5c1e89487f290744e9b839f1c7cd3e39b53bb073f64e537da7f7ec39d650","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"value","assisted_by":[],"external_id":"earth.climate-sensitivity.ecs-value","kind":"well-posed","literature_status":"partially-resolved","n":"1","parents":[],"plain":"Doubling CO2 will warm Earth by somewhere around 2.5 to 4 degrees once the oceans catch up. Narrowing that range has proved hard for decades.","posed_since":"1896","precise":"Equilibrium climate sensitivity (ECS) is the equilibrium global-mean surface air temperature change for doubled CO2 (forcing about $4\\mathrm{e}3\\,\\mathrm{erg}/(\\mathrm{s}\\,\\mathrm{cm}^{2})$). The 2020 multi-evidence assessment gives a 66 percent range of about $2.6\\ \\text{to}\\ 3.9\\,\\mathrm{K}$ and the 2021 IPCC assessment a likely range of $2.5\\ \\text{to}\\ 4\\,\\mathrm{K}$. An answer is a 66 percent range narrower than $1\\,\\mathrm{K}$ consistent with process, historical and paleoclimate evidence.","problem_ref":null,"references":"","settled_by":"Process-level constraints on cloud feedbacks combined with paleoclimate and historical energy-budget estimates that agree within a sub-kelvin range.","status_note":"","title":"What is Earth's equilibrium climate sensitivity?","topic_ref":"9825ae6297d7163c036f24262af4c46a63835d02712ce8b2f6de7b3820ec47e6"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"0c7c9ed5e2d8fd1bd3bece5152d8c6e1a644e52fc34fec7edad9f38e0680915e","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"4bb2a9092bcad7819d8e2b125409a8409273674af4dc5ea9d1bec61753a52562","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"w7bvv5ok7cnFWmMuRAH58_8w1uwGGNCncoBFBnMBhcUcQddS6v0LFWSHSa8SbcB7pzfskM95DE_6xjsYKFHkAg"},"schema":"pubphys.envelope/1"},"record_hash":"0c7c9ed5e2d8fd1bd3bece5152d8c6e1a644e52fc34fec7edad9f38e0680915e","leaf_index":1297}