New UN report says breaching the Paris Agreement threshold is now effectively unavoidable, but rapid emissions cuts could still limit the peak and eventually bring temperatures back below 1.5°C

New Delhi: Global warming is set to cross the critical 1.5°C threshold within the next few years, pushing climate risks and impacts to increasingly dangerous levels, the United Nations Environment Programme (UNEP) has warned in a major new assessment.

The new UNEP report, Limiting Overshoot – Navigating Exceedance of 1.5°C and Pathways Towards Return, says that exceeding 1.5°C is now widely assessed as unavoidable under current policies and near-term climate trajectories. However, the report stresses that crossing the threshold does not mean the fight against climate change is over.

The central challenge now is to ensure that any overshoot is as small and short-lived as possible and that the world retains the possibility of returning below 1.5°C later this century.

The warning comes as the planet is already experiencing unprecedented levels of warming. The World Meteorological Organization (WMO) says 2015–2025 were the 11 warmest years on record, while 2025 was the second or third warmest year ever recorded, with global temperatures around 1.43°C above the 1850–1900 pre-industrial average.

1.5°C threshold increasingly within sight

The 1.5°C figure became a central benchmark under the 2015 Paris Agreement, under which countries agreed to hold the increase in global average temperature to well below 2°C above pre-industrial levels while pursuing efforts to limit warming to 1.5°C.

The latest UNEP assessment, however, reflects a fundamental change in the climate outlook. The world has continued to emit large quantities of greenhouse gases, particularly carbon dioxide from fossil fuels, while emissions reductions have not been fast enough to keep warming below the 1.5°C level.

UNEP’s latest assessment says the world must therefore prepare for a period of temporary exceedance—or “overshoot”—of the 1.5°C threshold, while simultaneously pursuing much faster emissions reductions.

The distinction is important. The 1.5°C threshold is not a physical cliff beyond which climate impacts suddenly become catastrophic. Rather, every additional fraction of a degree increases risks, and the longer temperatures remain elevated, the greater the likelihood of severe and potentially irreversible consequences.

What happens when warming rises further?

The consequences of additional warming will be felt across virtually every major environmental and human system.

The Intergovernmental Panel on Climate Change (IPCC) has established that climate change is already affecting ecosystems, food systems, water resources, human health and infrastructure. As temperatures rise further, these risks become more severe.

A warmer atmosphere can hold more moisture, increasing the potential for intense rainfall in some regions, while changes in atmospheric circulation and precipitation patterns can worsen drought conditions elsewhere.

The IPCC has warned that climate change is intensifying the water cycle, contributing to more intense rainfall and flooding as well as more severe droughts in many regions.

Heatwaves are also becoming a major threat. Higher average temperatures raise the baseline from which extreme heat events develop, increasing risks to outdoor workers, older people, children and vulnerable communities.

Oceans, glaciers and coastal cities under mounting pressure. The consequences extend far beyond temperature records. Rising global temperatures contribute to glacier and ice-sheet loss and thermal expansion of seawater, driving long-term sea-level rise. Low-lying coastal regions and island nations are particularly exposed.

The IPCC says small islands are already experiencing increasing impacts from higher temperatures, tropical cyclones, storm surges, drought, changing rainfall patterns, sea-level rise, coral bleaching and invasive species.

For Small Island Developing States (SIDS), the threat is “existential”. Rising seas, coastal erosion, saltwater intrusion and increasingly damaging storms can undermine freshwater supplies, agriculture, housing, infrastructure and livelihoods.

Low-lying coastal cities around the world also face growing risks to roads, ports, drainage systems, electricity networks and buildings.

Food security could become increasingly fragile. Agriculture is another frontline of climate change. Higher temperatures, changing rainfall, drought, floods and increasingly frequent extreme weather events can reduce agricultural productivity and increase instability in food systems.

IPCC assessments indicate that crop productivity generally becomes increasingly vulnerable as warming progresses, although impacts vary between crops and regions.

For developing countries that are heavily dependent on rain-fed agriculture, climate shocks can translate directly into food insecurity, income losses and displacement.

The risks extend beyond crops. Warmer oceans, marine heatwaves, ocean acidification and ecosystem changes can also affect fisheries and other sources of food and livelihoods.

Biodiversity faces a compounding crisis. Nature is simultaneously a victim of climate change and a critical part of the solution.

Forests, wetlands, mangroves, grasslands, coral reefs and other ecosystems absorb and store carbon while providing essential services such as water regulation, coastal protection, pollination and food.

But ecosystems themselves have limits. As warming increases, species are pushed beyond the climatic conditions to which they are adapted. Coral reefs are particularly vulnerable to marine heatwaves and bleaching. Forest ecosystems face increasing pressure from heat, drought, wildfire, pests and changing rainfall.

The danger is that climate change and biodiversity loss can reinforce one another. When ecosystems deteriorate, their ability to store carbon and provide protection against climate impacts can also decline, potentially creating a vicious cycle.

The emissions gap remains enormous

The scale of the challenge is illustrated by UNEP’s latest emissions assessments. The 2025 Emissions Gap Report estimated that full implementation of countries’ climate pledges would still put the world on a pathway toward around 2.3–2.5°C of warming this century, while continuation of current policies could result in warming of up to 2.8°C.

That is substantially above the Paris Agreement’s temperature goals. UNEP has also estimated that achieving a 1.5°C-compatible pathway would require global greenhouse-gas emissions to fall by roughly 55% by 2035, compared with current levels—a scale of reduction far beyond existing commitments..

India and the developing world face a complex challenge

For countries such as India, the climate challenge involves balancing rapid development with a transition toward a low-carbon economy.

India is already experiencing multiple climate pressures, including extreme heat, changing rainfall patterns, floods, droughts and risks to agriculture, water security, health and infrastructure.

The country’s enormous development needs mean that climate action cannot be separated from questions of energy access, jobs, poverty reduction and economic growth.

The answer increasingly lies in accelerating clean-energy deployment while improving efficiency, building resilient infrastructure and protecting natural ecosystems.

The most important message from the latest UNEP assessment is that crossing 1.5°C should not be interpreted as a point of no return for climate action.

The scientific reality is more complicated

Some climate impacts may become irreversible on human timescales, while others can be reduced if warming is brought down. The longer and higher the overshoot, however, the greater the damage and the more difficult the recovery.

The world may no longer be able to prevent a temporary breach of 1.5°C, but it can still determine how far temperatures rise beyond it, how long they remain there and how much damage is ultimately locked in.

The difference between 1.6°C, 1.8°C, 2°C and higher warming is not merely a number on a thermometer. It represents different levels of risk for people, ecosystems, economies and future generations.

As UNEP’s latest assessment makes clear, the objective now must be to cut emissions as rapidly as possible, limit the overshoot, protect vulnerable communities and preserve the possibility of returning below 1.5°C. The climate window has narrowed dramatically, but it has not disappeared.