As global temperatures push beyond the Paris Agreement’s central threshold, scientists and climate experts are exploring a new strategy: limit the overshoot, reach a peak and bring temperatures back down.
In 2015, nearly every country on Earth agreed on a deceptively simple goal: keep global warming well below 2°C above pre-industrial levels while pursuing efforts to limit the increase to 1.5°C.
The adoption of the Paris Agreement represented an extraordinary moment of international cooperation.
More than a decade later, however, the world is approaching a point the agreement was designed to prevent.
Continued fossil fuel consumption and record greenhouse gas emissions mean that the 1.5°C threshold is increasingly expected to be breached in the coming years.
A new report from the United Nations Environment Programme (UNEP) argues that the failure to remain permanently below 1.5°C does not mean the climate goal should be abandoned.
Instead, the world may need a new strategy: overshoot, peak and decline.
Under this approach, global temperatures would temporarily rise beyond 1.5°C, reach a peak and eventually decline back below the threshold — potentially by the end of the century.
The longer the world remains above the threshold, however, the greater the risks.
Every Fraction of a Degree Matters
Climate change does not suddenly become dangerous at 1.5°C.
The risks increase progressively as temperatures rise.
Every additional fraction of a degree can intensify extreme heat, heavy rainfall, drought, wildfires and other climate-related hazards.
It can also increase pressure on coastal communities and small island states while accelerating the loss of biodiversity and ecosystems.
The consequences are already visible.
Recent catastrophic flooding in Nepal, which has killed more than 1,300 people and left thousands missing, has highlighted the vulnerability of communities exposed to rapidly changing environmental conditions, including the effects of melting glaciers.
Tom Rivett-Carnac, who helped shape the Paris Agreement, says an overshoot is increasingly difficult to avoid.
But avoiding a larger and longer overshoot remains critical.
The objective, he argues, should be to make the period above 1.5°C as limited and as brief as possible.
That requires immediate and sustained reductions in greenhouse gas emissions rather than treating the breach of the threshold as a reason to give up.
The Paris Agreement Has Made a Difference
The situation may appear bleak, but there has been meaningful progress since 2015.
Global temperature projections have improved considerably.
According to Rivett-Carnac, forecasts that once suggested warming of roughly 3°C to 3.5°C have fallen to around 2.3°C to 2.5°C under current policies and commitments.
The Paris Agreement helped accelerate investment in clean energy and significantly changed expectations about the future of renewable power.
But technological progress has not been matched by political action.
The original assumption was that as renewable energy became cheaper, governments would naturally become more ambitious about reducing fossil fuel use.
That transition has not happened quickly enough.
Fossil Fuels Remain at the Centre
Despite the rapid expansion of renewable energy, global fossil fuel consumption continues to rise.
International Energy Agency data cited in the report shows that carbon dioxide emissions increased again in 2025, reaching approximately 38.4 billion tonnes.
That is roughly 5 percent higher than in 2019.
The contradiction is becoming increasingly difficult to ignore.
Renewable technologies have become dramatically cheaper, yet the global economy remains heavily dependent on coal, oil and natural gas.
Solar power, for example, is now around 90 percent cheaper than it was in 2010, according to the International Renewable Energy Agency.
Renewables have also become the most cost-competitive option for new electricity generation in many markets.
More than 90 percent of utility-scale renewable projects commissioned in 2025 reportedly produced electricity at a lower cost than the cheapest new fossil-fuel alternative available in their respective markets.
The technology exists.
The economics are increasingly favourable.
What remains missing is the political willingness to move quickly enough.
“Political Courage” Is the Missing Ingredient
Mohammed Adow of Power Shift Africa argues that the central problem is no longer a lack of technological solutions.
The world knows how to produce cleaner electricity. It knows how to improve energy efficiency and reduce emissions.
The challenge is deploying those solutions at the scale and speed required.
That also means addressing the financial needs of developing countries, many of which face the greatest climate risks while having contributed comparatively little to historical emissions.
If the 1.5°C threshold is temporarily exceeded, abandoning the target altogether would be the wrong response, Adow argues.
Instead, the world should focus on reducing the overshoot and returning temperatures below the threshold as quickly as possible.
The United States and a Changing Climate Policy Landscape
Political decisions in major economies remain one of the biggest obstacles.
US climate policy has shifted sharply under Donald Trump, including withdrawal from the Paris Agreement.
The change in Washington has weakened momentum within global climate diplomacy at a time when international cooperation is considered increasingly important.
At the same time, global energy demand is changing.
One of the fastest-growing sources of electricity consumption is artificial intelligence.
The expansion of AI has triggered a massive increase in demand for data centres, which require enormous quantities of electricity to operate and cool their computing equipment.
In 2024, data centres supporting AI were estimated to account for approximately 1.5 percent of global electricity consumption.
That figure is expected to increase substantially by 2030.
AI’s Hidden Energy Problem
The technology industry’s climate ambitions are increasingly being tested by the energy demands of artificial intelligence.
Large technology companies are investing heavily in data-centre infrastructure, but many facilities continue to rely directly or indirectly on fossil-fuel-generated electricity.
Jan Rosenow, professor of energy and climate policy at the University of Oxford, argues that technology companies need to do more to ensure the rapid expansion of AI does not translate into an equivalent expansion of emissions.
One possible solution is making better use of waste heat.
Data centres generate enormous quantities of heat, much of which is currently released into the environment.
In some countries, including Sweden, waste heat from data centres is already being incorporated into district heating systems.
Such circular energy systems could help reduce wasted energy while lowering emissions.
The scale of the challenge, however, is enormous.
Reports have suggested that the combined emissions of major technology companies have risen substantially as AI infrastructure expands.
In the United States, proposed gas-fired power plants intended to supply growing data-centre demand could generate hundreds of millions of tonnes of greenhouse gas emissions each year.
The AI revolution could therefore become a significant new pressure on the world’s already strained climate targets.
Can Carbon Removal Buy Time?
If global temperatures temporarily exceed 1.5°C, reducing atmospheric carbon dioxide will become increasingly important.
The UNEP report therefore highlights carbon dioxide removal as one part of a future climate strategy.
Some approaches are relatively established, including reforestation, ecosystem restoration and other methods that increase natural carbon absorption.
Others are more controversial.
Carbon capture and storage technologies seek to capture carbon dioxide before or after it enters the atmosphere and store it underground.
Supporters argue that such technologies could help address emissions that are difficult to eliminate completely.
Critics point to the cost, technological challenges and enormous scale required to make them effective.
Rosenow argues that carbon removal can play a role, but it should not become an excuse to delay cutting emissions.
The logic is straightforward: preventing a tonne of carbon dioxide from entering the atmosphere is generally cheaper and more reliable than trying to remove it later.
A New Climate Strategy for a Warmer World
The 1.5°C target was never simply a number.
It represented an attempt to establish a boundary beyond which the risks of climate change could become increasingly severe and difficult to manage.
The world now appears increasingly likely to cross that boundary.
But crossing it does not necessarily mean the goal has become meaningless.
The emerging strategy of “limit overshoot, peak, decline” reflects a more complicated climate reality: temperatures may rise beyond 1.5°C, but the duration and magnitude of that overshoot will still matter enormously.
Every fraction of a degree avoided represents lives, ecosystems, food systems and economies potentially protected from greater damage.
The technologies needed to change course are increasingly available.
Renewable energy is cheaper than ever. Clean technologies are advancing rapidly. Carbon removal is developing. Even the energy-intensive technology sector has opportunities to redesign how it consumes and recycles power.
What remains uncertain is whether governments, businesses and societies will move quickly enough.
The climate window has narrowed, but it has not disappeared.
The challenge now is no longer simply to prevent 1.5°C.
It is to ensure that if the world crosses it, the overshoot is as small and as short-lived as possible — and that global temperatures eventually begin moving in the other direction.
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