Global warming will exceed limit, UN says in a report that maps path to get back below danger zone
A new United Nations Environment Programme (UNEP) report concludes that global warming will exceed the 1.5°C threshold above pre-industrial levels within the next few years, calling the breach effectively unavoidable
Current warming already stands at approximately 1.4°C above pre-industrial (mid-19th century) levels
The report, described as first-of-its-kind, maps an "overshoot, peak, and decline" pathway — warming crossing 1.5°C, peaking, and then gradually declining back below the threshold over subsequent decades
Under the most optimistic scenario modelled, warming would peak around 1.8°C by mid-century before declining; under current policy trajectories, warming could reach roughly 2.6°C by 2100
The report reframes global climate strategy from strictly preventing any breach of 1.5°C to minimising the magnitude and duration of the overshoot
The Paris Agreement (2015) and the 1.5°C Target
The Paris Agreement, adopted at COP21 in December 2015 under the UNFCCC, set the long-term temperature goal of holding the increase in global average temperature to well below 2°C above pre-industrial levels, while pursuing efforts to limit the increase to 1.5°C. It entered into force in November 2016 and India ratified it in October 2016. The 1.5°C figure was popularised as the "danger zone" threshold after the IPCC's 2018 Special Report on Global Warming of 1.5°C, which found that impacts (sea level rise, coral reef loss, extreme heat) escalate sharply between 1.5°C and 2°C.
Key Details
- Adopted: 12 December 2015 (COP21, Paris); entered into force 4 November 2016
- Legal form: binding agreement under the UNFCCC (1992), operating through voluntary Nationally Determined Contributions (NDCs) rather than binding national targets
- India's updated NDC (2022): reduce emissions intensity of GDP by 45% by 2030 from 2005 levels; achieve about 50% cumulative electric power installed capacity from non-fossil fuel sources by 2030
- The Paris Agreement itself does not define an "overshoot" mechanism — it is a scientific/policy concept developed in subsequent IPCC and UNEP assessments
The UNEP report does not abandon the Paris Agreement's 1.5°C goal but reinterprets the path to it — arguing the world must now approach 1.5°C "from above," through an overshoot-and-return trajectory, since staying permanently under the limit is no longer achievable given current emissions trends.
Overshoot Pathways in Climate Science
An "overshoot" scenario is one in which cumulative global emissions cause temperature to exceed a target threshold (like 1.5°C) before being brought back down through large-scale emission cuts and carbon dioxide removal (CDR). The IPCC's Sixth Assessment Report (AR6, 2021-2023) formally introduced overshoot pathways as a category of emissions scenarios, distinct from pathways that never exceed the target.
Key Details
- IPCC AR6 identifies overshoot magnitude and duration as key determinants of long-term climate risk — larger and longer overshoots risk triggering irreversible impacts (e.g., ice sheet loss, coral reef collapse)
- Carbon Dioxide Removal (CDR) technologies (afforestation, direct air capture, bioenergy with carbon capture) are central to any decline phase after peak warming
- The remaining global carbon budget for a 50% chance of staying within 1.5°C was estimated by the IPCC at roughly 500 gigatonnes of CO2 from 2020, a budget that recent assessments (including this UNEP report) confirm has now been largely exhausted
The report's "peak and decline" framing is a direct application of the IPCC's overshoot pathway concept to real-world emissions trajectories, using it to argue that a temperature peak followed by decades of decline is now the most realistic route back toward the Paris goal.
UNEP's Role in the Global Climate Architecture
The United Nations Environment Programme, headquartered in Nairobi, Kenya, is the UN's principal environmental authority, established in 1972 following the Stockholm Conference on the Human Environment. UNEP produces the annual Emissions Gap Report, which tracks the difference between countries' pledged emissions cuts and the cuts needed to meet the Paris temperature goals; this overshoot report extends that assessment work.
Key Details
- UNEP established: 1972, headquartered in Nairobi
- Annual flagship publication: Emissions Gap Report (since 2010), which quantifies the gap between current NDC pledges and required reductions
- UNEP works alongside the IPCC (established 1988, WMO/UNEP joint body) which provides the scientific assessments underpinning UNFCCC negotiations
This overshoot report is UNEP's latest contribution to the evidence base that informs UNFCCC Conference of Parties (COP) negotiations, signalling a shift in the diplomatic framing of the 1.5°C goal ahead of future COPs.
- Current global warming: approximately 1.4°C above pre-industrial levels
- Paris Agreement threshold: 1.5°C (aspirational), well below 2°C (binding long-term goal)
- Most optimistic scenario: warming peaks near 1.8°C around mid-century before declining
- Current policy trajectory: approximately 2.6°C of warming projected by 2100
- Paris Agreement adopted: 12 December 2015 (COP21); entered into force: 4 November 2016
- India's NDC target (2022 update): 45% emissions-intensity reduction by 2030 (from 2005 levels); ~50% non-fossil power capacity by 2030