Stabilizing time-lagged climate impacts requires net-negative emissions for centuries

[Geoengineering News]

https://iopscience.iop.org/article/10.1088/1748-9326/ae34ca

Authors: Johannes Bednar, Artem Baklanov, Justin Macinante, Jim W Hall, Thomas Gasser and Michael Obersteiner

07 January 2026

Abstract

In July 2025, the International Court of Justice (ICJ) affirmed that States must prevent significant harm to the environment, including the climate system. Some of the most critical climate impacts, such as sea level rise (SLR) and permafrost thaw (PFT), will intensify for centuries even under 1.5–2 °C stabilization. In the terms expressed by the ICJ, we argue a duty exists to pursue stabilization of impacts at the lowest attainable levels. Using ensembles from a coupled integrated assessment and earth system model emulator, we show that achieving this requires sustained global net-negative CO2 emissions well beyond the 23rd century. Crucially, delayed mitigation does not increase carbon debts as under overshootable temperature-based targets, but instead increases long-term impacts, the likelihood of extreme outcomes, and shifts mitigation burdens further to future generations. These findings suggest that Paris targets are milestones, not endpoints, and that sustained carbon removal must become a structural element of future climate governance. In the ICJ’s terms, this points to a plausible legal trajectory toward recognizing sustained global carbon removal obligations. Robust frameworks to define and fairly distribute these obligations, both among nations and across generations, are essential yet currently absent from international climate governance.

Source: IOP Science