WMO Confirms 2023–2025 as Hottest Period on Record

The World Meteorological Organisation (WMO) has declared that the three years since 2023, along with the decade-long span from 2015 to 2025, have been the hottest periods ever recorded. In its “State of the Global Climate Update 2025”, the agency warned that 2025 is on track to become the second or third-warmest year in history, with global temperatures currently averaging 1.4°C above pre-industrial levels.

Record Heat and Ocean Changes

The WMO report highlights that the oceans are absorbing unprecedented amounts of heat, intensifying global warming impacts. Arctic sea ice reached its lowest winter extent ever recorded, while Antarctic ice remained significantly below average. Sea levels continue to rise globally, driven by warming oceans and melting glaciers, although temporary dips have occurred due to La Niña and related factors. The cumulative effect has increased the frequency and intensity of extreme weather events, including heatwaves, floods, and wildfires.

Temperature Patterns and El Niño Impact

Between January and August 2025, the mean near-surface temperature was recorded at 1.42°C above pre-industrial averages. The 26-month stretch from June 2023 to August 2025 broke monthly heat records almost continuously. While El Niño conditions boosted global temperatures during 2023 and 2024, 2025 saw a transition to neutral or La Niña phases. Despite this moderation, overall temperatures remained abnormally high, underscoring the persistence of human-driven climate change.

Sea-Level Rise and Glacier Loss

Ocean heat content in 2025 has surpassed last year’s record levels, absorbing over 90 per cent of the excess heat caused by greenhouse gases. The average sea-level rise rate has accelerated from 2.1 mm per year in the 1990s to about 4.1 mm annually since 2016. The hydrological year 2023–2024 marked the third consecutive year of glacier mass loss, with around 450 gigatonnes of ice melted — the largest ice loss since 1950 — contributing 1.2 mm to sea-level rise.

Exam Oriented Facts

• The WMO confirmed 2023–2025 as the hottest three-year period on record, with global temperatures 1.4°C above pre-industrial levels.
• Sea-level rise has nearly doubled from 2.1 mm per year in the 1990s to 4.1 mm since 2016.
• 2023–2024 saw a record glacier loss of 450 gigatonnes of ice, equivalent to 1.2 mm sea-level rise.
• CO₂ concentration reached 423.9 ppm in 2024 — a 53% increase since pre-industrial times.

Global Warming Outlook and Climate Action

WMO Secretary-General Celeste Saulo warned that limiting warming to 1.5°C is becoming increasingly difficult without briefly exceeding it. UN Secretary-General António Guterres, addressing the Belém Climate Summit (COP30), urged rapid global action to curb emissions, noting that every year above 1.5°C will deepen inequality and harm economies. The WMO emphasised the urgent need to expand multi-hazard early warning systems, which have doubled since 2015 but still leave 40 per cent of nations unprotected. As renewable energy capacity grows, accurate climate forecasting is seen as vital for building resilient and sustainable power systems worldwide.