New Delhi, Sept 2 (NVI) United Nations Environment Programme (UNEP) has predicted that global temperatures are likely to rise above 1.5°C from pre-industrial levels within the next few years.
In a report, titled Limiting Overshoot, the UNEP says the focus of climate action needs to shift towards limiting how far temperatures rise above the threshold and bringing them down again as quickly as possible as there are now no plausible scientific pathways that can keep global warming below 1.5°C.
The 1.5°C target is a central pillar of the 2015 Paris Agreement where nations pledged to keep global warming well below 2°C while striving to limit it to 1.5°C.
Although the threshold was breached temporarily in 2024, when global temperatures averaged 1.55°C above pre-industrial levels to mark the warmest year on record, the World Meteorological Organization (WMO) emphasizes that the Paris target measures long-term warming over decades rather than a single year.
However, the UNEP warns that annual temperatures could soon stay consistently above 1.5°C. With long-term global warming already reaching approximately 1.4°C, the multi-decade threshold could be crossed within a few years.
UNEP says the amount of warming the world sees will depend on how quickly countries cut greenhouse gas emissions.
About 1.8°C: This is the most optimistic scenario and would require countries to fully meet their current climate pledges and long-term commitments.
More than 2°C: If countries do less than this, global temperatures could rise above 2°C.
About 2.6°C: If current government policies continue without stronger action, warming could reach a median estimate of 2.6°C by 2100.
This means the world is likely to cross 1.5°C even in the most optimistic scenario. However, UNEP stresses that every fraction of a degree matters.
The higher temperatures rise, and the longer they stay elevated, the greater the risks to people, ecosystems and the planet.
UNEP says Climate Action must now prepare for an “overshoot, peak and decline” pathway. This means temperatures would first exceed 1.5°C, then reach a peak before gradually falling again.
However, returning below the threshold will be difficult and highly uncertain. It would require rapid reductions in greenhouse gas emissions as well as large-scale removal of carbon dioxide that is already present in the atmosphere.
Carbon dioxide removal could include measures such as reforestation and technologies designed to capture carbon from the atmosphere.
Yet UNEP stresses that carbon removal cannot replace deep cuts in emissions, while existing carbon removal efforts have so far had limited impact.
Even optimistic scaling is unlikely to reduce temperatures by more than a few tenths of a degree this century.
Crossing 1.5°C does not mean that a single new climate disaster will occur suddenly. Instead, existing risks are expected to become more severe and frequent as global temperatures continue to rise.
These include:
More intense heatwaves and extreme weather
- Greater pressure on glaciers and ecosystems
- Rising risks for low-lying coastal cities
- Greater threats to food, water and livelihoods
- Increasing chances of irreversible environmental damage
UNEP warns that even if temperatures eventually fall below 1.5°C, some losses and changes may be permanent.
UNEP says the world must now focus on making the period above 1.5°C as small and as short as possible.
To make this possible, UNEP calls for:
- Rapid cuts in greenhouse gas emissions, including methane, to reach net-zero as soon as possible
- Faster transition from fossil fuels to renewable energy, which can also improve air quality and public health
- Stronger adaptation measures to help communities, economies and infrastructure cope with worsening climate impacts
- Responsible carbon dioxide removal, including afforestation and other methods, to help bring temperatures down after the peak. (NVI)
