Global warming is approaching a critical threshold, with the world increasingly likely to experience temperatures above 1.5°C of pre-industrial levels. A new assessment from the United Nations Environment Programme (UNEP) says governments must respond with faster emissions cuts, stronger adaptation measures and long-term efforts to restore climate stability.

The warning comes as climate change continues to intensify heatwaves, wildfires, floods, droughts and other extreme events across different parts of the world. UNEP’s latest Limiting Overshoot report says crossing 1.5°C should not be treated as a permanent destination. Instead, countries should work to keep the temperature overshoot as low and short-lived as possible before attempting to bring global temperatures back down.

A New Climate Reality

The 1.5°C target has been a central element of international climate policy since the adoption of the Paris Agreement. But UNEP now says exceeding that level is becoming increasingly difficult to avoid.

The organization’s most optimistic pathway projects global warming peaking around 1.8°C, while several other pathways point to substantially higher temperatures. The difference between these outcomes matters because every additional fraction of a degree can increase risks to ecosystems, economies, infrastructure, food supplies and human health.

The report emphasizes that temperature overshoot should be viewed as a trajectory rather than a single moment. How high temperatures rise, how long they remain elevated and whether they eventually decline will depend heavily on decisions made during the coming years.

Three Priorities for the Global Response

The emerging climate challenge requires action on several fronts at the same time.

1. Immediate Action

The first priority is a rapid reduction in greenhouse gas emissions. Governments need to accelerate the transition away from fossil fuels, expand renewable energy and cut methane emissions.

UNEP argues that reaching net-zero emissions is essential for stopping further warming, but net-zero alone will not necessarily return global temperatures below 1.5°C after an overshoot. Faster emissions reductions now can reduce the eventual temperature peak and limit the damage caused by climate change.

2. Containment of Climate Risks

The second priority is preventing the temperature overshoot from becoming larger and lasting longer than necessary.

UNEP says mitigation and adaptation cannot be treated as separate climate policies. Communities must reduce emissions while simultaneously preparing cities, agriculture, water systems, infrastructure and economies for increasingly severe climate impacts.

Keeping the temperature peak as low as possible can also make adaptation more manageable and less expensive.

3. Long-Term Resilience and Recovery

The third priority is building resilience for a future in which some climate impacts may no longer be reversible.

UNEP warns that even if temperatures eventually decline, the planet will not simply return to its previous state. Rising seas, ecosystem changes, ice loss, species decline and human displacement can continue for decades or longer because different parts of the Earth system respond at different speeds.

This means governments will need long-term strategies that address climate resilience, economic adjustment, relocation and protection of vulnerable communities.

Carbon Removal Has a Role — But Cannot Replace Emission Cuts

The UNEP assessment also highlights carbon dioxide removal as one potential component of a pathway back toward lower temperatures.

Carbon removal can involve approaches such as restoring forests and improving soil carbon storage, as well as technologies designed to capture carbon dioxide directly from the atmosphere. But UNEP stresses that these methods should supplement, rather than replace, deep reductions in greenhouse gas emissions.

Technological carbon removal remains expensive and faces significant challenges involving energy use, land requirements, permanent storage and governance. For this reason, relying heavily on future removal technologies while delaying emissions cuts could increase climate risks.

Equity Must Be at the Centre

Climate change does not affect every country or community equally. Vulnerable populations often face the greatest consequences despite having contributed relatively little to historical emissions.

UNEP therefore emphasizes that equity and justice must be built into climate action. Countries with greater responsibility for accumulated emissions should move faster and demonstrate stronger ambition, while developing nations require adequate financial and technical support to protect their populations and transition toward cleaner economies.

This also creates difficult questions about the future. If certain regions become increasingly difficult to inhabit, governments will have to address migration, livelihoods, infrastructure and the distribution of resources.

Stronger International Cooperation Needed

The scale of the climate challenge means individual countries cannot solve it independently. UNEP identifies political commitment, effective multilateral cooperation, inclusive governance and climate finance as important conditions for success.

International cooperation will be particularly important for accelerating renewable energy, reducing methane emissions, financing adaptation and developing responsible carbon-removal systems.

The report’s message is not that crossing 1.5°C means the climate fight is over. Instead, it argues that every fraction of a degree avoided matters.

The Window for Action Is Narrowing

The world is entering a period in which climate decisions will have consequences lasting far beyond the current generation. A higher temperature peak would increase the likelihood of severe and potentially irreversible changes, while a shorter period of warming above 1.5°C could reduce some of those risks.

UNEP’s central message is therefore straightforward: governments must act immediately, strengthen resilience and cooperate internationally rather than treating climate overshoot as an excuse for inaction.

The challenge is no longer simply preventing every possibility of crossing 1.5°C. It is also determining how high temperatures rise, how long they remain elevated and how quickly humanity can bring them down again.

The choices made now will shape that trajectory for decades to come.