The world is likely to breach the 1.5C warming limit again soon, according to a new forecast from the World Meteorological Organization (WMO) and the UK Met Office. Scientists predict a 91 per cent chance that at least one year in the five-year period from 2026 to 2030 will temporarily exceed this critical threshold, and a 75 per cent likelihood that the average temperature across those five years will be more than 1.5C above the 1950–1990 average.
The 1.5C target was enshrined in the Paris Agreement, adopted in 2015, which commits nations to holding global temperature rise to “well below 2C” above pre-industrial levels and to pursue efforts to limit it to 1.5C. The threshold is not a physical cliff edge but a point beyond which the risks of severe impacts to ecosystems and human systems increase significantly, scientists warn. Every increment of warming above 1.5C matters, raising the likelihood and severity of climate impacts such as water stress, desertification, damage to major crops, and species extinction. Crucially, exceeding 1.5C – even temporarily – raises the chance of crossing climate “tipping points”, critical thresholds beyond which Earth systems may undergo abrupt, self-perpetuating and potentially irreversible changes, such as the collapse of ice sheets or disruption of ocean currents. The concept of “overshoot” – temporarily exceeding 1.5C and then returning – is a growing concern, because even if temperatures come back down, the world will be more damaged than if the limit had never been breached, with irreversible consequences for ecosystems and potentially higher long-term vulnerability for societies.
The WMO and Met Office forecast that annual global mean near-surface temperatures between 2026 and 2030 will range between 1.3C and 1.9C above the pre-industrial baseline of 1850–1900. There is also an 86 per cent chance that one of those years will surpass 2024 as the warmest year on record worldwide. The El Niño phenomenon, predicted for late 2026, could make 2027 a record-breaking year. The primary driver of the rising temperatures is the accumulation of heat-trapping greenhouse gases in the atmosphere, the report states.
The 75 per cent probability that the five-year average from 2026 to 2030 will exceed 1.5C marks a stark escalation. The past 11 years – 2015 to 2025 – were the 11 warmest on record, and 2025 was confirmed as one of the three warmest years, with the consolidated three-year average of 2023–2025 standing at 1.48C above pre-industrial levels.
The warning follows 2024’s temporary breach of the 1.5C limit, the first single year in which global average surface temperature exceeded that benchmark. Scientists describe such single-year or monthly exceedances as early warning signs and “clarion calls for increasing ambition and accelerating action”. While the Paris Agreement goal refers to a long-term average over decades, the 2024 breach and the latest forecast underscore how close the world is to sustained warming above the agreed limit.
Global and UK implications
The WMO forecast is global, but its repercussions are felt locally. The Met Office’s UK Climate Projections (UKCP18) provide detailed data on how Britain’s climate may change. By 2070, under a high emissions scenario, summer maximum temperatures in the UK are projected to increase by 3.8C to 6.8C, with hot summer days becoming sixteen times more frequent over southern parts of the country. Summers are expected to become generally drier, yet the intensity of summer rainfall events is projected to increase, with the frequency of hourly rainfall exceeding 30mm per hour doubling by 2070 – raising the risk of more frequent and severe flooding. Winters are expected to be wetter, and sea levels around the UK are projected to rise, with potential increases of up to 1.15m for London by the end of the century under high emissions.
The UK government is legally required to adapt to climate change under the Climate Change Act 2008. The third National Adaptation Programme (NAP3) sets out actions for 2023–2028 to boost resilience to temperature extremes, flooding and water scarcity. However, the Climate Change Committee (CCC) has highlighted that current adaptation efforts are insufficient and has called for increased investment in cooling, flood preparedness and water management. On mitigation, the UK has a legally binding target to reach net zero greenhouse gas emissions by 2050, and a target for clean power to meet 100 per cent of electricity demand by 2030, with at least 95 per cent from low-carbon sources. But the UK’s 2030 target is noted as being 2 per cent short of 1.5C compatibility, and current policy projections need acceleration, according to assessments cited in the research briefing.
Public concern about climate change remains high – 77 per cent of UK adults expressed concern in Winter 2025 – but has declined since 2021, with the cost-of-living crisis and NHS worries overshadowing environmental priorities for some. Support for renewable energy is still around 80 per cent, though the intensity of that support has softened. Support for specific policies such as low-traffic neighbourhoods and taxes on flying has fallen. There is a “perception gap”: the public underestimates the level of backing for climate action, potentially inducing hesitancy, while most people do not identify as climate sceptics or activists.
Scientific consensus on human-caused climate change stands at between 98.7 per cent and 100 per cent among climate experts. Scientists have long warned that exceeding 1.5C raises the risk of crossing climate tipping points. While some literature suggests certain tipping points may already have been triggered at current warming levels of around 1.1C, more are likely if the 1.5C threshold is surpassed, though debate continues over the certainty and immediacy of each.
