UNEP Report Details Pathways to Limit Global Warming to 1.5°C

The United Nations Environment Programme (UNEP) published a report on September 2, 2026, stating that global temperatures are projected to surpass 1.5 °C above pre-industrial levels within the next few years. The report examines available strategies to address this projected overshoot and outlines the requirements for returning temperatures below this threshold.

According to the UNEP report, the only remaining viable route to limit warming involves an “overshoot, peak, and decline” pathway. This approach requires first limiting the maximum temperature increase, then reducing global temperatures back below 1.5 °C by mid-century through a combination of sustained emission reductions and long-term net-negative emissions using Carbon Dioxide Removal (CDR) methods.

The report emphasizes that while CDR is necessary, its contribution to reducing temperatures this century is limited to a few tenths of a degree. UNEP states that CDR cannot replace the need for substantial and immediate reductions in greenhouse gas emissions, including methane, to meet the 1.5 °C target.

To achieve a return to below 1.5 °C this century, the report states that peak warming must be limited to approximately 1.8 °C. Without immediate and sustained emission cuts, combined with carefully managed CDR, UNEP warns that the 1.5 °C goal will not be met.

What the numbers show

• Emissions must fall by 55% by 2035 compared to 2019 levels to align with the 1.5 °C pathway.
• Current national pledges do not meet the required emission reduction levels.
• Returning to 1.5 °C by 2100 is technically possible with faster and larger emissions reductions and reliance on CDR.

UNEP’s Emissions Gap Report 2025 found that, to stay on track for the 1.5 °C target, global emissions need to be reduced by more than half by 2035 compared to 2019 levels. However, the report notes that current national commitments are insufficient to achieve this reduction.

The Emissions Gap Report 2025 also states that limiting the period of overshoot and returning to 1.5 °C by the end of the century remains technically possible. Achieving this would require accelerated and larger-scale emissions reductions, as well as increased reliance on carbon dioxide removal technologies, which remain uncertain in their effectiveness and scalability.

Background information from the Intergovernmental Panel on Climate Change (IPCC) indicates that all analyzed pathways limiting warming to 1.5 °C with no or limited overshoot depend on CDR to neutralize emissions that cannot be otherwise mitigated. These pathways often require achieving net-negative emissions after a peak in warming to return to the target threshold.

The IPCC also states that delays in reducing carbon dioxide emissions increase the likelihood of exceeding the 1.5 °C threshold and necessitate greater reliance on net-negative emissions technologies later in the century. This underscores the importance of immediate and sustained mitigation efforts alongside the development of CDR solutions.

* This article is based on publicly available information at the time of writing.