TL;DR: The United Nations now says breaching 1.5°C of warming within the next few years is unavoidable, and urges an "overshoot, peak and decline" strategy to limit the peak and return below 1.5°C by the end of the century.

UN declares 1.5°C breach unavoidable

In a strategic retreat in the fight against climate change, the United Nations acknowledged on Sept. 2, 2026, that Earth has lost its chance to prevent some of the worst harms of global warming, according to The Associated Press via NBC News.

Earth is soon going to exceed the safe temperature threshold agreed upon by the world in the 2015 Paris climate accord because of warming from the burning of coal, oil and gas, according to the bleak first-of-its-kind report issued Wednesday by the United Nations Environment Programme.

The report, titled Limiting Overshoot, examines the implications of entering an era of 1.5°C overshoot and the choices that remain available, according to the UNEP publication page for Limiting Overshoot - Navigating exceedance of 1.5°C and pathways towards return.

UNEP describes overshoot as a dynamic pathway encompassing the exceedance of 1.5°C, peak warming and subsequent temperature decline, according to that UNEP publication page.

The finding marks a shift from years in which U.N. officials maintained that the 1.5-degree window was still open despite experts saying there was no way to limit warming to that level, according to The Associated Press via NBC News.

Wednesday's report finally admitted that the world will cross the 1.5 threshold "in the next few years," according to The Associated Press via NBC News.

UNEP said global temperature rise is set to cross 1.5°C, likely within the next few years, pushing climate risks and impacts to increasingly dangerous heights, according to the UNEP press release titled UNEP: World set to cross 1.5°C global warming, but can still limit, adapt to and return from higher temperatures.

The report identifies an "overshoot, peak, and decline" pathway as the best remaining option to minimize the magnitude and duration of this overshoot and try to return to below 1.5°C as soon as possible, according to that UNEP press release.

"Humanity is speeding past the limit to avoid climate catastrophe," United Nations Secretary-General António Guterres said, according to The Associated Press via NBC News.

In his video message on the launch of the UNEP overshoot report, Guterres said leaders pledged 10 years ago in Paris to limit temperature rise to 1.5°C, described as the threshold scientists say is critical to avoiding the worst climate devastation, according to the UN Meetings Coverage account of his message.

That UN account states that Guterres said the world is failing to keep that promise and is set to breach the 1.5°C limit within the next few years.

Where temperatures stand now

After the Paris climate accord, the United Nations ordered its climate science arm to study different warming limits, according to The Associated Press via NBC News.

A goal of 1.5 Celsius (2.7 Fahrenheit) above mid-19th century temperatures became generally accepted after scientists found dramatic impacts that affect people and the planet at 2 degrees Celsius (3.8 degrees Fahrenheit) but not at 1.5 degrees, according to The Associated Press via NBC News.

The world is now at 1.4 C (2.5 F) above pre-industrial levels, as calculated by some scientists, according to The Associated Press via NBC News.

That measure is based on a 20-year average, rather than a single year's temperatures, according to The Associated Press via NBC News.

The year 2024 was the first year the threshold was exceeded every month but until a long-term exceedance was recorded, the UN held that the agreement was not breached, according to The Irish Times.

UNEP states that limiting global warming to 1.5°C remains a cornerstone of the Paris Agreement, yet under current policies and alternative near-term trajectories, exceedance of 1.5°C is now widely assessed as unavoidable, according to the UNEP publication page.

The goal of limiting average global temperature rise to 1.5 degrees above pre-industrial levels — before fossil fuel use accelerated — was set in the 2015 Paris Agreement, signed by almost all the world's countries, according to The Irish Times.

How high the peak could go

The report said the most optimistic scenario has warming peaking at 1.8 C (3.2 F) around midcentury if countries pursue ambitious climate goals, according to The Associated Press via NBC News.

That optimistic case assumes full implementation of all national climate plans plus meeting additional net-zero targets, according to the UNEP publication page summary.

Governments' current policies should push temperatures to 2.6 C (4.7 F) above pre-industrial levels by 2100, according to The Associated Press via NBC News.

Current policies point to a rise of about 2.6°C by 2100, with a range of 1.9–3.6°C, according to The Hindu.

The most optimistic scenario will see temperature rise peak at 1.8°C above pre-industrial levels, above the goal set by the Paris Agreement, while most other scenarios predict higher peaks, according to the UNEP press release.

The report envisions that global temperatures will pass 1.5 "within the next few years," follow a hump-shaped path of more warming, peak, then gradually cool to below the 1.5 mark, ideally by the end of the century, according to The Associated Press via NBC News.

The report and experts call that pattern "overshoot," according to The Associated Press via NBC News.

The overshoot is expected to last several decades, with the "most optimistic scenario" — if behaviours change immediately and dramatically — marking a temperature rise kept to 1.8 degrees, according to The Irish Times.

A reversal to 1.6 degrees could then be possible by the end of the century under that optimistic framing, according to The Irish Times.

However, the report's international team of authors warn most scenarios predict a rise of more than 2 degrees and a return to or below 1.5 degrees is uncertain, according to The Irish Times.

The news journal Nature reported Sept. 2 that Earth will breach the long-standing target before the end of the decade and that the best the planet can hope for on its current emissions trajectory is warming of about 1.8°C above pre-industrial levels this century, according to Nature.

The plan to come back down

So instead of preventing warming of 1.5 degrees, now the U.N. said it wants policymakers to "prepare for and navigate a future" in which the globe crosses that limit and then corrects course and cools temperatures, according to The Associated Press via NBC News.

"Let's be very clear, 1.5 target is still the goal. But now we need to approach it differently from above," UNEP Executive Director Inger Andersen said, according to The Associated Press via NBC News.

After a period of over-the-limit warming, the new strategy envisions getting back below the limit by ending fossil fuel use and developing some kind of way to suck industries' carbon dioxide out of the air, according to The Associated Press via NBC News.

That pathway would minimize peak temperature rise through immediate and sustained cuts to greenhouse gas emissions, including methane, on the road to net-zero, according to the UNEP press release.

It would then bring down temperatures through long-term net-negative emissions, with carefully governed Carbon Dioxide Removal — the process of removing carbon from the air and storing it through afforestation or other means — described as an essential part of the mix, according to that UNEP press release.

The report emphasizes that net-zero is a milestone towards net-negative, with Carbon Dioxide Removal needed in addition to, not instead of, sustained reductions in greenhouse gas emissions, according to the UNEP press release.

That removal can only contribute credibly to a return below 1.5°C if peak warming remains well below 2°C and all residual emissions are reduced, according to the UNEP press release.

Strong governance frameworks for Carbon Dioxide Removal will be critical to allow responsible deployment and manage implications for environmental integrity, equity and scale, according to the UNEP press release.

"It's a reality check. We have to live with this warmer world," report co-author Richard Betts, a climate scientist at the University of Exeter, said, according to The Associated Press via NBC News.

Betts added that there is still a lot that can be done to limit warming, according to The Associated Press via NBC News.

Limiting how high temperatures go past the threshold is key, with Andersen saying it is most important to first limit the new peak temperature and then reduce the amount of time above 1.5 degrees, according to The Associated Press via NBC News.

The world likely will be in that overshoot period for "many, many decades," Betts said, according to The Associated Press via NBC News.

Every five years of delay in reducing emissions adds at least a tenth of a degree to peak warming, said report co-author Joeri Rogelj, a climate scientist at Imperial College London, according to The Associated Press via NBC News.

"If we act now we can limit overshoot," the report said. "Not a safe world, but safer than remaining above" 1.5 degrees for the long term, according to The Associated Press via NBC News.

What overshoot means for people and technology

During this overshoot period, more people will die or get sick because of worsening climate change and its extreme weather, the report said, according to The Associated Press via NBC News.

Food production will drop, people will go hungry, water shortages will worsen, economies will be hurt and species like coral will go extinct, the report said, according to The Associated Press via NBC News.

Instead of giving up, scientists and U.N. officials recommend trying to limit excessive warming and then bringing the temperature back down, but it still will mean decades of increased weather-related disasters, rising seas, extinctions and melting ice and glaciers, according to The Associated Press via NBC News.

Above 1.5°C, risks and impacts will intensify with every extra fraction of a degree and every year, with anticipated impacts including intensified extreme weather, ecosystem loss, and submersion of Small Island Developing States and low-lying coastal cities, according to the UNEP press release.

Severe damage to human health, food security, water supplies, nature, cities, infrastructure, and economies is expected, according to the UNEP press release.

The report warns that the likelihood of crossing irreversible tipping points increases with the magnitude and duration of higher temperatures, according to the UNEP press release.

Those include the destabilization of major ice sheets, degradation of the Amazon rainforest and disruption of the Atlantic Meridional Overturning Circulation, described as the system of currents that moves warm surface water north and cold deep water south and plays a key role in regulating the climate, according to the UNEP press release.

Permanent sea-level rise will also occur and disruption is expected to the Atlantic meridional overturning circulation, the currents that moderate weather in many countries including Ireland, according to The Irish Times.

Irreversible impacts include glacier loss, with more catastrophes such as the recent landslides in Nepal, according to The Irish Times.

Guterres said this summer's scorching heat, raging wildfires and deadly floods are a warning of what lies ahead and that every fraction of a degree will cost lives, destroy livelihoods, deepen inequality and push ecosystems closer to irreversible damage, according to the UN Meetings Coverage account.

Governments need to increase efforts to adapt to worsening warming, which hits the poor hardest, "because some impacts simply cannot be avoided," Andersen said, according to The Associated Press via NBC News.

The report calls this phase "coping and containment," according to The Associated Press via NBC News.

The 1.5 limit is not "some magical climate cliff" where it is just game over, said University of Victoria climate scientist Andrew Weaver, who was not part of the study, according to The Associated Press via NBC News.

Weaver said every tenth of a degree avoided still means less damage, according to The Associated Press via NBC News.

What leaders are asked to do next

Guterres said the overshoot must be made as small and short as possible, which demands an overshoot of ambition, according to the UNEP press release.

That demands accelerating the phaseout of fossil fuels and the renewables revolution, slashing methane pollution, and protecting land, forest and oceans, according to the UN Meetings Coverage account of his message.

Governments must over-deliver on national climate plans, net-zero commitments and beyond, according to that UN Meetings Coverage account.

Developed countries must triple adaptation finance and ensure it reaches those most at risk, according to that UN Meetings Coverage account.

Strong political will and multilateralism, effective policies, inclusive governance, and finance are all important enabling conditions for action — and equity and justice must underpin all responses, according to the UNEP press release.

Countries with greater responsibility for climate change should act the fastest with the greatest ambition, according to the UNEP press release.

Mitigation and adaptation, which are mutually reinforcing, must advance together, while being responsive to emerging risks, according to the UNEP press release.

Interventions that achieve both mitigation and adaptation goals — such as nature-based cooling — should be prioritized, according to the UNEP press release.

Sources referenced