SYLLABUS
GS-3: Environment Conservation, environmental pollution and degradation, environmental impact assessment.
Context: The UN Environment Programme (UNEP), in its report Limiting Overshoot, warns that the world is likely to cross 1.5°C of global warming within the next few years.
More on the News
- Report puts best-case scenario peak temperature rise at 1.8°C; others suggest over 2°C
- Above 1.5°C, climate impacts and risks of tipping points intensify with every fraction of a degree.
- ‘Overshoot, peak and decline’ pathway best remaining option to help vulnerable nations and communities cope and return to below 1.5°C .
Why is 1.5°C Important?
- The 1.5°C limit under the Paris Agreement represents an important effort to limit climate risks.
- UNEP warns that once warming exceeds this level, climate impacts and risks increase with every additional fraction of a degree and every passing year.
- The most optimistic scenario in the report projects a peak temperature rise of 1.8°C, while most other scenarios indicate higher peaks.
- Higher warming could intensify extreme weather, ecosystem loss and damage to human health, food security, water supplies, infrastructure, cities and economies. It could also increase risks to Small Island Developing States and low-lying coastal cities.
Why Is the Breach Considered Inevitable?
- Shrinking Carbon Budget: Earlier IPCC assessments provided a narrow window to limit warming to 1.5°C, but UNEP now says this is no longer scientifically plausible.
- Carbon Budget Exhaustion: The Indicators of Global Climate Change report estimates that the 1.5°C carbon budget could be exhausted in around three years if emissions continue at current levels.
- New Priority: The focus is now on limiting the extent of warming beyond 1.5°C.
Recent Temperature Trends
- 2024 Breach: Global temperature reached around 1.55°C above pre-industrial levels, making 2024 the warmest year recorded.
- Monthly Breaches: Several months between July 2023 and December 2024 recorded temperatures of at least 1.5°C above pre-industrial levels.
- Role of El Niño: The 2024 record was significantly influenced by El Niño, while warming declined to around 1.45°C in 2025.
- Long-Term Concern: UNEP warns that annual temperatures are now moving towards consistently remaining above 1.5°C.
Growing Risk of Climate Tipping Points
- The magnitude and duration of higher temperatures also increase the likelihood of crossing irreversible climate tipping points.
- These include the destabilisation of major ice sheets, degradation of the Amazon rainforest and disruption of the Atlantic Meridional Overturning Circulation (AMOC), which transports warm surface water northward and cold deep water southward.
- Some impacts could occur abruptly, while others may accumulate gradually.
Mitigation and Adaptation: Two Sides of Climate Action
- UNEP stresses that mitigation and adaptation must advance together.
- Rapid emissions reductions and a transition away from fossil fuels towards renewable energy can limit warming while also providing benefits such as better air quality, improved public health, lower energy costs and greater electricity access.
- At the same time, adaptation must reduce the vulnerability of communities, economies and societies to current and future climate impacts. The report calls for transformational and responsive adaptation, particularly as climate risks can become non-linear or emerge suddenly.
- Measures that provide both mitigation and adaptation benefits, such as nature-based cooling, should receive greater attention.
Role of Carbon Dioxide Removal
- The report considers net-zero a milestone towards net-negative emissions. CDR will be necessary for bringing temperatures below 1.5°C, but it must be used in addition to sustained emissions reductions, not as a substitute for them.
- CDR can credibly contribute to a return below 1.5°C only if peak warming remains well below 2°C and residual emissions are reduced.
- Strong governance will also be required to address concerns related to environmental integrity, equity and scale.
Way Forward
- Climate action should focus on sustained emissions reduction, responsible scaling of CDR, stronger climate finance, and unified global action to minimise the 1.5°C overshoot.
- The success of this pathway depends on strong political will, multilateralism, effective policies, inclusive governance and adequate finance. Equity and justice must remain central to climate responses.
- Countries with greater responsibility for climate change should undertake faster and more ambitious action.