RCP2.6: exploring the possibility to keep global mean temperature increase below 2°C

TLDR

RCP2.6 is a low‑emission mitigation pathway that limits global mean temperature rise to 2 °C, represents the most stringent scenarios in the literature, and often requires negative emissions in the second half of the 21st century. The study examines how the climate system responds to a peak radiative forcing, whether society can achieve the necessary emission‑reduction rates amid political and social inertia, and how non‑CO₂ emissions can be further curtailed. Using the IMAGE integrated assessment model, RCP2.6 is shown to be technically feasible from a medium‑emission baseline with full global participation, requiring a 70 % reduction in cumulative GHGs from 2010 to 2100, with bio‑energy and reforestation measures driving land‑use changes and prompting recommendations for further low‑emission research.

Abstract

The RCP2.6 emission and concentration pathway is representative of the literature on mitigation scenarios aiming to limit the increase of global mean temperature to 2°C. These scenarios form the low end of the scenario literature in terms of emissions and radiative forcing. They often show negative emissions from energy use in the second half of the 21st century. The RCP2.6 scenario is shown to be technically feasible in the IMAGE integrated assessment modeling framework from a medium emission baseline scenario, assuming full participation of all countries. Cumulative emissions of greenhouse gases from 2010 to 2100 need to be reduced by 70% compared to a baseline scenario, requiring substantial changes in energy use and emissions of non-CO2 gases. These measures (specifically the use of bio-energy and reforestation measures) also have clear consequences for global land use. Based on the RCP2.6 scenario, recommendations for further research on low emission scenarios have been formulated. These include the response of the climate system to a radiative forcing peak, the ability of society to achieve the required emission reduction rates given political and social inertia and the possibilities to further reduce emissions of non-CO2 gases.