World heads for 2.8°C warming – and even climate pledges fall short

The world is heading for 2.8°C of warming by the end of this century under current climate policies, calculations published on Wednesday, 21 October, by the Nairobi-based UN Environment Programme (UNEP) show. Even if every announced climate measure were implemented, temperatures would rise by 2.6°C above pre-industrial levels. For Switzerland, the stakes are high: further warming threatens health, alters water availability and increases hazards in the mountains.

The central message is that existing efforts are insufficient, while political reversals affect the global temperature outlook. The projection under current policies is unchanged from last year. For the scenario covering all announced measures, it has worsened: the previous estimate was for warming of up to 2.5°C.

Three scenarios, none meets the goal

The temperature figures reflect different assumptions. The 2.8°C estimate follows from policies already in place. The 2.6°C figure assumes countries deliver the measures they have announced. In the most optimistic scenario, every country also fulfils its climate-neutrality targets. Even then, the planet would warm by 2.1°C by 2100.

That distinction matters. A long-term pledge does not itself cut emissions: it requires practical changes to energy supplies, transport, buildings and industry. These calculations are therefore not predictions of an unavoidable future. They show where different political and economic paths could lead.

The deterioration in the outlook for announced measures is largely due to the United States. Under President Donald Trump, the country has abandoned its previous climate plans. As the world’s second-largest emitter of greenhouse gases after China, it has a substantial influence on the global picture. Figures for past greenhouse gas emissions have also been revised upwards.

The 2015 Paris Agreement aims to keep warming well below 2°C while pursuing efforts to limit it to 1.5°C. Even the most favourable scenario exceeds those thresholds.

Why every fraction of a degree matters

The 1.5°C threshold has not yet been crossed in the sense used by the long-term climate goal. That depends on sustained warming, rather than a single exceptionally hot year. For 2023–2025, the European climate service Copernicus records average warming above 1.5°C across a three-year period for the first time. It is a warning, but not the same as a long-term breach.

Experts now generally expect that an overshoot can no longer be avoided. That brings a second task into focus: keeping it as small and brief as possible, before bringing global temperatures down again.

UN Secretary-General António Guterres stresses that overshooting does not mean surrender. Temperatures could still be brought back below 1.5°C by the end of the century, while limiting the scale and duration of the overshoot.

Doing so would require deep cuts. Compared with 2025 levels, global greenhouse gas emissions would need to fall by 18 per cent by 2030, 45 per cent by 2035 and 69 per cent by 2040. Yet full implementation of planned measures would deliver reductions of only up to eight per cent by 2030 and up to 15 per cent by 2035. Large quantities of CO₂ would also have to be removed from the atmosphere.

What a warmer world means for Switzerland

Global warming is not evenly distributed. Switzerland has already warmed more than the worldwide average. A global increase of 2.8°C therefore cannot be read as an identical temperature rise in every Swiss town or village.

The consequences reach both urban neighbourhoods and mountain communities. Heatwaves place particular strain on older people, those with chronic illnesses and people working outdoors. In densely built-up areas, buildings and roads retain heat. A lack of cooling overnight adds to the health burden.

In the Alps, shrinking glaciers change the seasonal availability of water. Thawing permafrost can destabilise rock faces, putting transport routes, settlements and tourism infrastructure at risk. Less reliable snow conditions also increase the pressure on winter tourism to adapt.

Not every individual natural event can be attributed solely to climate change. Nevertheless, a warmer atmosphere and changing conditions in the mountains influence the risks. For residents, the implications extend beyond hotter summers to the stability and reliability of the landscape and infrastructure around them.

Switzerland has enshrined its goal of net-zero greenhouse gas emissions by 2050 in law. How much the country warms will nevertheless depend heavily on developments worldwide. Cutting domestic emissions and preparing for unavoidable consequences therefore remain parallel responsibilities, rather than alternatives.

Pressure builds before the next climate summit

Despite the large gap between pledges and the cuts required, UNEP executive director Inger Andersen points to progress. Renewable energy has expanded considerably faster than expected since the Paris Agreement, particularly solar photovoltaics. Technological change is possible, but it must translate more quickly into falling emissions.

The next political opportunity is the forthcoming global climate conference in Antalya, Turkey. Its leadership is promoting a worldwide electrification target. The crucial question is how the additional electricity will be generated: electrification helps tackle climate change above all when it replaces fossil fuels with low-emission energy supplies.

Financing emissions reductions and adaptation in developing countries is equally important. Alongside the shift in energy systems, that will test whether long-term commitments become effective measures in time. For Switzerland, as elsewhere, the difference between the scenarios is not merely numerical: it shapes the scale of the changes people will have to prepare for.