2025 Set to Be Among Hottest Years Ever as WMO Warns of Escalating Climate Crisis

The report reveals that the ocean heat content—which represents over 90% of trapped climate energy—continued its record-breaking rise in 2025, building on 2024’s unprecedented levels.

The World Meteorological Organization (WMO) has released its State of the Global Climate Update for 2025, painting a grim picture of the Earth’s rapidly warming climate system. According to the report, 2025 is on track to be the second or third warmest year ever recorded, capping an alarming trend of 11 consecutive years of record-breaking heat from 2015 to 2025—each now ranking among the 11 warmest years since global temperature records began in 1850.

Between January and August 2025, the global near-surface temperature averaged 1.42°C (±0.12°C) above pre-industrial levels, further narrowing the margin toward the 1.5°C threshold established in the Paris Agreement—a marker that, once surpassed, signals more frequent and devastating climate impacts.

Overshoot of 1.5°C Increasingly Likely

Speaking at the UN Climate Change Conference (COP30) in Belém, Brazil, WMO Secretary-General Celeste Saulo warned that unless global emissions fall drastically, temporary overshoot of 1.5°C is virtually unavoidable in the near term. However, she emphasized that stabilizing the climate below this level by century’s end remains possible with urgent and coordinated global action.

UN Secretary-General António Guterres, citing the WMO’s findings at the Belém Climate Summit, echoed this concern:

“Each year above 1.5 degrees will hammer economies, deepen inequalities and inflict irreversible damage. We must act now, at great speed and scale.”

Ocean Heat and Sea Levels Rising at Alarming Rates

The report reveals that the ocean heat content—which represents over 90% of trapped climate energy—continued its record-breaking rise in 2025, building on 2024’s unprecedented levels. This silent but powerful indicator has far-reaching consequences:

• Accelerates melting of glaciers and sea ice

• Weakens the ocean’s role as a carbon sink

• Fuels stronger tropical storms

• Contributes to the collapse of marine ecosystems

This rising heat directly fuels sea level rise, which has nearly doubled since the 1990s, from 2.1 mm/year (1993–2002) to 4.1 mm/year (2016–2025). While a brief dip occurred in 2025 due to La Niña effects, long-term projections remain sharply upward.

Polar Ice Reaching New Lows

Arctic and Antarctic sea ice continued to dwindle:

• Arctic sea-ice extent hit a record low winter maximum of 13.8 million km² in March and declined to 4.6 million km² in September—well below the long-term average.

• Antarctic sea-ice extent was the third lowest on record in both February (2.1 million km²) and September (17.9 million km²).

Glaciers in Global Retreat

Data from the World Glacier Monitoring Service showed net mass loss across all monitored glacial regions for the third year in a row. The 2023/2024 season witnessed a mass balance of -1.3 meters water equivalent, contributing around 1.2 mm to sea level rise—the largest ice loss recorded since 1950.

Greenhouse Gases Hit Record Highs

Levels of carbon dioxide, methane, and nitrous oxide—the primary greenhouse gases—reached record concentrations in 2024 and are projected to climb even higher in 2025. Notably:

• CO₂ levels rose to 423.9 ppm in 2024, up 53% from pre-industrial levels.

• The year-on-year increase of 3.5 ppm from 2023 to 2024 marked a record spike.

These figures underscore the widening gap between climate targets and actual emission trends.

Catastrophic Climate Extremes Disrupt Lives

Throughout 2025, a series of extreme climate-related events wreaked havoc across continents:

• Devastating floods swept parts of Africa and Asia

• Wildfires raged through Europe and North America

• Prolonged heatwaves battered populations globally

• Tropical cyclones triggered mass displacement and infrastructure loss

The cumulative effect of these events undermines food systems, economies, and public health, compounding inequality and forcing climate-induced migration.

Energy Sector Stretched by Extreme Heat

The record heat of 2024 triggered a 4% spike in global energy demand relative to the 1991–2020 average. Regions such as Central and Southern Africa experienced demand surges of up to 30%, putting strain on energy systems.

With renewable energy expansion underway, the WMO stresses that climate-informed planning is critical to building resilient and flexible clean energy infrastructure.

Progress and Gaps in Climate Services and Early Warning

The WMO report highlights mixed progress in climate services and early warning systems:

• Multi-Hazard Early Warning Systems (MHEWSs) have doubled in use—from 56 countries in 2015 to 119 in 2024. Yet, 40% of nations still lack them, posing a major vulnerability.

• Climate services—such as seasonal outlooks and heat-health alerts—are now offered by two-thirds of National Meteorological and Hydrological Services (NMHSs), compared to just 35% five years ago.

As part of the UN’s Early Warnings for All (EW4All) initiative, efforts are underway to reach universal coverage by 2027. However, sustained investment is critical to closing the remaining gaps, especially for Least Developed Countries (LDCs) and Small Island Developing States (SIDSs).

---

A Call to Ground Policy in Science

The WMO’s State of the Global Climate Update 2025 serves as a scientific cornerstone for COP30 negotiations, ensuring that decisions on mitigation, adaptation, and finance are anchored in empirical evidence. The report emphasizes the growing need to integrate climate intelligence into policymaking, particularly in vulnerable sectors like agriculture, energy, water, and public health.

As the world gathers in Belém to chart the next steps under the Paris Agreement, the evidence is sobering but clear: without transformative action now, the window to prevent catastrophic climate outcomes is rapidly closing.