Closing the fossil carbon cycle: the Geological Net Zero Pact (FR : Boucler le cycle du carbone fossile : le pacte de Neutralité Géologique en Carbone)

Closing the fossil carbon cycle: the Geological Net Zero Pact. Working version 0.9 Climate disruption results first of all from the transfer of carbon accumulated over millions of years in geological reservoirs into the atmosphere, the ocean and the biosphere, at a pace that natural cycles cannot offset. The Geological Net Zero (GNZ) principle was proposed for COP26 in 2021 and has since been consolidated in the scientific literature. It draws an accounting rule from this: any extraction of fossil carbon must be balanced by a permanent and verified return of carbon to the geosphere. Between COP26 and COP31, the carbon budget compatible with 1.5 °C shrank from 420 to 170 billion tonnes of CO₂. This document reviews that period and explains why a pact between carbon actors is preferable to a resolution imposed from above. It then presents the GNZ Pact: implementation by segments of supply chains, spreading until a critical threshold is reached; its parties and its five commitments; its accounting and the economic model it induces; how it fits with atmospheric CO₂ removal and with fossil fuel transition roadmaps. It ends with a flexible action plan based on demonstrators and verifiable commitments. Contents of this record Founding article, French and English versions Perspective, condensed version for journal submission, French and English versions Status. Working version 0.9, released on the occasion of COP31 (Antalya, 9–20 November 2026) and subject to revision; version 1.0 is expected in December 2026. This is a scientific and public-policy proposal open for discussion. It does not refer to an adopted treaty or an existing certification scheme, and it does not reflect the position of any organisation or person cited. Website: geologicalnetzero.org