The United Nations has warned that a triple-whammy of the hottest years on record threatens irreversible damage, as nations prepare for the Cop30 climate summit in Brazil. The UN World Meteorological Organization (WMO) said 2023, 2024 and 2025 are set to be the three hottest years in 176 years of records, with 2025 on course to be the second or third hottest. The past 11 years, back to 2015, will also be the 11 warmest on record, demonstrating the depth of the climate crisis.
The WMO said limiting global heating to the Paris agreement target of 1.5C above preindustrial levels is now virtually impossible. Celeste Saulo, the WMO secretary-general, stated: “The unprecedented streak of high temperatures, combined with last year’s record increase in greenhouse gas levels, makes it clear that it will be virtually impossible to limit global warming to 1.5C in the next few years without temporarily overshooting this target.” However, she added that it remains possible to bring temperatures back down to 1.5C by the end of the century through carbon dioxide removal, such as growing new forests and using technology to capture and bury CO2.
UN Secretary-General António Guterres described missing the 1.5C target as a moral failure, saying: “Each year above 1.5C will hammer economies, deepen inequalities and inflict irreversible damage.” He urged action to make any overshoot as small, short and safe as possible. Scientists fear that overshooting the target could trigger climate tipping points and cause catastrophic damage.
Despite the accelerating rollout of renewable energy and electric vehicles, nations are falling drastically short of the action needed to cut carbon emissions. The WMO reported in October that CO2 levels in the atmosphere soared by a record amount in 2024. Scientists are concerned that natural carbon sinks, such as forests and oceans, are weakening due to global heating, potentially creating a vicious circle that drives temperatures up faster.
The WMO report also highlighted that the hydrological year up to October 2024 saw the largest loss of glacier ice since records began in 1950, with 450 billion tonnes of ice lost, pushing up sea levels. Extreme weather is becoming more intense and frequent due to the climate crisis, making early warning systems more vital. The number of countries with multi-hazard early warning systems has more than doubled since 2015, from 56 to 119 in 2024, but 40% of countries still lack them, and urgent action is needed to meet the UN goal of universal coverage by 2027.
