Beyond 1.5°C: Putting people at the heart of policy

Climate overshoot on the horizon

A recent United Nations Environment Programme (UNEP) report, Limiting overshoot: Navigating exceedance of 1.5°C and pathways towards return, has made headlines for its shocking conclusions: global action to cut greenhouse gas emissions has not been fast enough, and warming is set to exceed 1.5°C above pre-industrial levels within the next few years. Even in the most optimistic situation – where every national climate plan is fully implemented and all additional net-zero targets are delivered upon – the expected peak warming is around 1.8°C.

No scenarios above 1.5°C are easy to come to terms with: sea levels rising at a faster pace; a higher likelihood of ecosystem collapse, including coral reefs, more extreme heat and wildfires; and profound changes to the cryosphere (ice sheets, sea ice, glaciers, permafrost and snow). Glaciers could lose more than a quarter of their mass by 2100, raising sea levels by 9 to 12.5 cm and permanently altering water availability across whole regions. Some Small Island Developing States (SIDS) and low-lying coastal cities face partial or complete submersion. Without effective adaptation, global food production could decline by up to 14% by 2050. More frequent and intense heatwaves, more nutrition-related disease and greater risk of pathogen spillover will drive illness and death. And the risk grows of crossing irreversible tipping points in the West Antarctic and Greenland ice sheets, the Atlantic Meridional Overturning Circulation (the system of currents that moves warm surface water north and cold deep water south, playing a key role in regulating the climate) and the Amazon rainforest. These are thresholds that would reshape the world permanently.

The ‘peak and decline’ imperative

It is tempting to read this as the crossing of a point of no return, where nothing can be done and humanity’s only option is to surrender to the inevitable.

That reading is wrong, and resisting it matters.

Since exceeding the 1.5°C threshold is now inevitable, a shift in focus is unavoidable. The aim now must be to limit how high temperatures rise, ensure that they stay above the threshold for as short a period as possible, and bring them back down as soon as possible. The UNEP report describes this not as resignation but as ‘constrained agency’. The logic is simple and unforgiving. The lower the peak, the lower the risk. The shorter the overshoot, the lower the chance of crossing irreversible thresholds. The sooner emissions fall, the more future loss and damage can be avoided. And the report’s central operational lesson is that mitigation and adaptation can no longer be sequenced: they are mutually supporting pillars that must advance together.

An undeniable reality for Europeans

For Europeans, climate overshoot is no longer a projection. The scorching summer of 2026 has shown that its implications are already part of ordinary life. While the EU has legislated for carbon neutrality by 2050, current projections suggest the 2030 target of a 55% reduction on 1990 levels will be narrowly missed, with a further 6.5 percentage points of the projected reduction dependent on planned measures not yet enacted in legislation.

While policymakers are grappling with this new reality, policy design routinely underestimates an important factor, compounded by the urgency highlighted by UNEP. Climate policy instruments are frequently designed for a citizen who does not exist: one who is fully informed, unburdened by distractions or anxiety, able to absorb upfront costs and capable of navigating bureaucracy.

Across the EU, 84% of citizens agree that human activity causes climate change, and 94% recognise the urgent need to adapt. Often, however, citizens who, in principle, hold pro-environmental values and support environmental objectives do not translate them into everyday choices about energy, mobility, food and consumption.

A to-do list for policymakers

Eurofound’s research paper Mapping green behavioural public policy in the EU explains why and what policymakers could actually leverage in a context of constrained agency. While many interventions are possible, three overarching lessons lay the foundations for green behavioural public policy.

Make shared beliefs visible: support for collective action matters most when it is recognised and shared by others. This may be the cheapest lever available. Collective pro-environmental motivation within a group is a predictor of a greater willingness to invest in renewable energy and accept renewable energy policies, and the effect is stronger among those who identify strongly with the group. This holds at every level, from the municipality to the country to EU citizenship itself. People are also more willing to change their own behaviour when they believe others, particularly those who are better off, are changing theirs. Yet they systematically underestimate how much others are willing to contribute. One study found that once young people realised that they had underestimated the level of climate concern among older generations, they gained a stronger belief in collective action; telling them instead about generational differences in causes and impacts simply made them more worried. The lesson is that accurate information about our neighbours, communities and groups is more motivating than more information about the climate.

Don’t focus solely on the negative, but highlight also the positive steps that are being taken. Worry translates into action far more reliably when people believe action affects both their own lives and everyone else’s. This means worry must be paired with agency and effectiveness. Furthermore, evidence suggests that government efficacy – trust in the state’s capacity to actually reduce emissions – matters more than personal efficacy in shaping climate attitudes. That is a directly implementable finding for policymakers: visibly delivering on a climate commitment is not merely good administration, it is itself a behavioural intervention.

Choose the messenger with care, and protect and nurture trust in the evidence, the rule-maker and the implementer. This lesson is not new for policymakers; however, evidence has shown that at least three critical trust systems matter for the just green transition. Trust in scientists and environmental organisations shows the strongest association with pro-environmental behaviour, while trust in institutions generally is less important and only weakly related to private-sphere behaviour such as household energy use. Trust in government does something different: it does not change behaviour directly but it predicts whether citizens will accept policies designed to influence their behaviour, such as nudges (gentle design changes that steer behaviour without forbidding options or changing economic incentives) and defaults (automatic options that occur if a person does nothing). Without that acceptance, green behavioural policy lacks legitimacy. And trust in the specific actors delivering a project – the developer or the municipality, for example – predicts its local acceptance.

Trust in the evidence, trust in the rule-maker and trust in the implementer are not interchangeable, and citizens may not always have trust in all three. In practice, this means that policymakers must know who is trusted, by whom, and on what. Failures have been well documented: in one EU energy-efficiency support scheme, promotional material fronted by politicians backfired because public trust was low, while welfare officers who already had relationships with the target households were able to convey the information more successfully.

The power of policy and behaviour

Climate overshoot can read as a narrowing of the space for action. It should, however, be read as the opposite. UNEP’s framing is that every fraction of a degree avoided, every year by which exceedance is shortened and every investment in resilience preserves future options. Overshoot is not a reason to lower ambition; it is a reason to heighten it.

It is also a statement about policy design. If each year and each tenth of a degree matter, then the rate at which policy converts into actual change matters more than it did before. This is where behavioural public policy earns its place, not as an alternative to regulation, pricing and investment, but as the layer that determines whether those instruments land. Designing for human beings as they actually are is not a softer agenda than emissions targets. It is part of what makes targets deliverable, fairer, more accessible and more actionable in the process.