UNEP Warns World Will Cross 1.5°C Global Warming Threshold, But Return Below It Is Still Possible – Indian PSU

The world is likely to cross the critical 1.5°C global warming threshold within the next few years, exposing communities and ecosystems to increasingly severe climate risks. However, a new report by the United Nations Environment Programme (UNEP) says it is still possible to limit the duration and magnitude of this overshoot and eventually bring global temperatures back below 1.5°C.

The UNEP report, “Limiting Overshoot: Navigating Exceedance,” identifies an “overshoot, peak and decline” pathway as the best remaining option for reducing the scale of warming beyond 1.5°C and improving the prospects of returning below the Paris Agreement temperature goal.

The most optimistic scenario assessed in the report projects global warming peaking at around 1.8°C above pre-industrial levels, while several other scenarios foresee a peak of more than 2°C.

Every Fraction of a Degree Matters

UNEP warns that once warming exceeds 1.5°C, climate-related risks will increase with every additional fraction of a degree and every additional year spent at higher temperatures.

The consequences could include more intense heatwaves, wildfires and floods, accelerating ecosystem degradation, threats to food and water security, damage to infrastructure and economies, and growing risks to human health.

Small Island Developing States and low-lying coastal cities are particularly vulnerable to rising seas and other climate impacts.

The report also highlights increasing risks of climate tipping points as temperatures rise and remain elevated for longer periods. These include destabilization of major ice sheets, degradation of the Amazon rainforest and disruption of the Atlantic Meridional Overturning Circulation (AMOC), a major system of ocean currents that helps regulate the global climate.

Some of these changes could occur abruptly, while others could build progressively over decades.

Immediate Emission Cuts Critical

UNEP says the overshoot, peak and decline pathway requires immediate and sustained reductions in greenhouse gas emissions, including rapid cuts in methane emissions, followed by achieving net-zero emissions.

In the longer term, net-negative emissions would be required to bring global temperatures down. Carefully governed Carbon Dioxide Removal (CDR) could play an important role by removing carbon dioxide from the atmosphere and storing it through approaches such as afforestation and other removal technologies.

However, UNEP stresses that carbon removal must complement—not replace—deep and sustained reductions in greenhouse gas emissions.

CDR could contribute credibly to returning temperatures below 1.5°C only if peak warming remains well below 2°C and residual emissions are brought down substantially.

Adaptation Must Happen Alongside Mitigation

The report emphasizes that reducing emissions alone will not be enough. Countries and communities must simultaneously strengthen their ability to cope with the climate impacts that are already occurring and those expected in the future.

Adaptation measures can reduce vulnerability and limit economic and social damage, although UNEP warns that adaptation has limits. Some climate impacts could become irreversible, particularly if temperatures remain elevated for extended periods.

Measures that provide both mitigation and adaptation benefits should therefore receive priority. UNEP points to nature-based cooling as one example of interventions capable of delivering benefits on both fronts.

Guterres Calls for an “Overshoot of Ambition”

UN Secretary-General António Guterres said the extreme weather experienced around the world is a warning of what lies ahead.

“This summer’s scorching heat, raging wildfires and deadly floods are a warning of what lies ahead,” Guterres said, stressing that the overshoot above 1.5°C must be made “as small and short as possible.”

UNEP Executive Director Inger Andersen similarly warned that there are no good outcomes from remaining above 1.5°C.

“Across the globe, extreme heatwaves are already proving that climate impacts will strike faster, hit harder, and last longer,” Andersen said, calling for stronger action to cut emissions, strengthen resilience and ensure that any exceedance of 1.5°C is as limited and short-lived as possible.

Climate Action Requires Finance, Equity and Political Will

UNEP says the transition will depend not only on technology but also on political will, effective policies, multilateral cooperation, inclusive governance and adequate climate finance.

The report places particular emphasis on equity and justice. Countries that have contributed most to historical greenhouse gas emissions, it argues, should move fastest and demonstrate the greatest ambition.

Mitigation and adaptation must also progress together and remain responsive to emerging risks.

A rapid shift away from fossil fuels towards renewable energy could provide benefits beyond climate mitigation, including cleaner air, improved public health, potentially lower energy costs and expanded access to electricity.

A Return Below 1.5°C Will Not Erase the Damage

Even if the world eventually succeeds in bringing temperatures back below 1.5°C, UNEP warns that the period of overshoot would leave lasting consequences.

Some ecosystems and communities could experience irreversible losses. People may be forced to relocate, livelihoods could change permanently and governments may face difficult decisions over resources, compensation, adaptation and resettlement.

The report therefore frames the overshoot, peak and decline pathway as a next-generation climate frontier—but one that requires action now.

The longer governments delay substantial emissions reductions, the higher the eventual peak is likely to be and the harder, more expensive and more disruptive the journey back below 1.5°C could become.

The central message from UNEP is clear: crossing 1.5°C is increasingly likely, but the size and duration of the overshoot are still within humanity’s ability to influence. Immediate, sustained and coordinated climate action will determine what happens next.

The writer of this article is Dr. Seema Javed, an environmentalist & a communications professional in the field of climate and energy