State of the Global Climate 2025.

 

 The Earth’s climate is more out of balance than at any time in observed history, as greenhouse gas concentrations drive continued warming of the atmosphere and ocean and melting of ice, according to the World Meteorological Organization (WMO). These rapid and large-scale changes have occurred within a few decades but will have harmful repercussions for hundreds – and potentially thousands – of years. State of the Global Climate 2025

The global climate system is complex. In order to unpack such complexity, the WMO State of the Global Climate 2025 uses Climate Indicators to describe the changing climate. The following site aims to provide an overview of the annually produced State of the Climate report . Please note that for some indicators, 2025 data is not yet available. The latest available data is provided where this is the case.

Greenhouse Gases

Increasing levels of greenhouse gases, like carbon dioxide, in the atmosphere due to human activities are a major driver of climate change. Real-time data show that global greenhouse gas emissions continued to increase in 2025. The Big Three: Carbon dioxide (CO 2) is the most important greenhouse gas, and is measured in parts per million (ppm). Methane (CH 4) and nitrous oxide (N 2 O) are also important for the global climate and are measured in parts per billion (ppb). In 2024, the latest year for which global data are available, record values were reached: Carbon dioxide: 423.9 ± 0.2 ppm = 152% of pre-industrial levels. Methane: 1942±2 ppb = 266% of pre-industrial levels. Nitrous oxide: 338.0±0.1 ppb = 125% of pre-industrial levels. As greenhouse gases are trapping more heat in the Earth system, the balance of energy incoming and outgoing is changing. This changing balance is referred to as "the Earth's Energy Imbalance", a new indicator in this year's report. As the trapped energy accumulates, it raises temperatures on land and in the ocean and leads to melting glaciers and ice sheets. Earth's energy imbalance has been growing since the 1960s, reaching a record high in 2025. This heat accumulating in the climate system, is warming the planet.

Global Mean Surface Temperature

As more energy is trapped in the Earth system, global mean surface temperature (GMST) is rising. GMST is measured using a combination of air temperature over land, and sea surface temperature in ocean areas, typically expressed as a difference from a baseline period. 2025 was second or third warmest year on record. It was approximately 1.43 ± 0.13 °C warmer than the pre-industrial (1850-1900) average. But temperature isn't rising uniformly everywhere. Greenland, northern Canada, western Europe, Fennoscandia, the Mediterranean and many parts of Asia experienced signficant warm anomalies.

Precipitation

Compared to temperature, precipitation—like rain or snow—varies much more across different places and times, meaning some areas may face droughts while others experience record floods. In 2025, areas with significantly above normal precipitation are shown in green. Meanwhile, regions with significant rainfall deficits are shown in brown. What was precipitation like where you live?


Ocean Heat Content

As greenhouse gases accumulate in the atmosphere, temperatures increase on land and in the ocean. Around 90% of the extra heat trapped by greenhouse gases is absorbed by the ocean, causing it to warm and affecting marine life, weather patterns, and sea levels. "Ocean Heat Content" measures how this energy warms the ocean at various depths, down to 2000m deep. It is expected that the ocean will continue to warm well into the future – a change which is irreversible on centennial to millennial time scales. The ocean continued to warm in 2025, reaching record high levels. But why does ocean warming matter?

Coral bleaching

Corals are extremely sensitive to temperature changes. Their health is vital as they create entire ecosystems, serve as a source of food for millions, protect coastlines from storms and erosion and can be key tourist attractions.

Sea Level Rise

As water warms, it expands. Therefore, rising ocean temperatures are a key contributor to rising sea levels around the globe.

Sea Level Rise

The global sea level is rising for a number of reasons. Ocean warming and melting ice sheets and glaciers all contribute, along with changes in how water is stored on land. In 2025, global mean sea level was comparable to the record-high levels observed in 2024 in the satellite altimetry record. The long-term rate of sea-level rise has increased since the start of the satellite record, increasing from 2.65 mm per year between 1993-2011 to 4.75 mm per year between 2012-2025. It's just a few millimeters, what's the big deal? Most of the world's megacities are in coastal areas, with millions of people living in low-elevation coastal zones (LECZ). Even just a few millimeters of rise can have a big impact on coastal flooding and erosion, putting populations at increased risk from storms and floods, salt-water intrusion. Sea-level rise will bring cascading and compounding impacts. Losses of coastal ecosystems and ecosystem services, groundwater salinization, flooding and damage to coastal infrastructure all cascade into risks to livelihoods, settlements, health, well-being, food, displacement, water security, and cultural values in the near to long-term.

Ocean Acidification

Another impact of rising CO 2 concentration is ocean acidification. The ocean absorbs around 29% of the annual emissions of anthropogenic CO 2 to the atmosphere, helping to alleviate the impacts of climate change but at a high ecological cost to the ocean. CO 2 reacts with seawater and increases its acidity. It endangers organisms and ecosystem services, including food security, by endangering fisheries and aquaculture. It also affects coastal protection by weakening coral reefs, which shield the coastline, and encourage tourism. As the pH of the ocean decreases, meaning that its acidity increases, its capacity to absorb CO 2 from the atmosphere also declines. Global mean ocean surface pH has been steadily declining at rates not seen for at least the past 26,000 years.

Sea Ice Extent

Changes in global temperature resulting from increasing greenhouse gases also impact bodies of ice, both at sea and on land. Sea ice extent is a useful indicator of climate change, particularly given how quickly change is occurring in the Arctic. In 2025, both the Antarctic and Arctic regions experienced below average sea ice extent throughout the year.

Arctic Sea Ice

Arctic sea-ice saw its lowest maximum extent on record in 2025, peaking at approximately 14.19 ± 0.40 million km 2 compared with the average maximum of 15.07 ± 0.38 million km 2 .

Antarctic Sea Ice

Antarctic sea-ice extent reached a minimum of 2.06 ± 0.10 million km 2 between 23 February and 1 March 2025, tied for the second lowest minimum on record. The past four years have seen the four lowest Antarctic ice minima on record, far below the average minimum of 2.93 ± 0.14 million km 2 .

Glacier Mass Balance

Glaciers are found around the world, with many in the high mountain ranges of Asia, and North and South America. They are formed from snow that has compacted to ice, which then flows downhill to lower, warmer altitudes, where it melts. Glaciers provide ecosystem services and freshwater to millions around the world. As they shrink, there are significant and direct impacts on water resources and sustainable development. Full data for 2025 is not yet fully available, but preliminary observations indicate that 2024-2025 was another year of extremely negative mass balance worldwide. What does mass loss look like? Swipe to see what an Icelandic glacier looked like between 2017 and 2025: Copernicus Sentinel-2 imagery


Extreme Events


Human-caused climate change is already affecting many weather and climate extremes in every region across the globe, including cold and heat waves, floods, droughts, wildfires and storms. This has led to widespread adverse impacts and related losses and damages to nature and people. More details on specific events can be found in the report and the extremes supplement .Explore theInteractive map of extreme events in 2025 as reported by WMO Members.


Risks & Impacts

Impacts on Sustainable Development.

Rising atmospheric CO₂ concentrations are driving changes across the climate system, influencing extreme weather and putting progress toward the Sustainable Development Goals (SDGs) at risk. For example, rising temperatures are having a tremendous impact on human health.


Spotlight on heat, health & dengue

Dengue  -  Climate change is influencing both the geography and seasonality of infectious diseases that are sensitive to temperature and precipitation. Dengue is the world’s fastest-growing mosquito-borne viral disease; According to the World Health Organization (WHO), about half of the world’s population is at risk of dengue and reported cases are currently the highest ever recorded. Dengue transmission is influenced by multiple social, environmental and health system factors. However, higher temperatures play a critical enabling role and climate suitability for dengue transmission has increased substantially over recent decades. Changes in rainfall patterns have also influenced breeding sites and population dynamics, expanding risk into new regions, and lengthening transmission seasons in areas where dengue is already endemic.

South-west Asia drought


Rainfall for the 12 months ending June 2025 was 50% or more below normal over much of the Islamic Republic of Iran, as well as parts of other countries in the region, including Syria and Jordan. Significant water shortages were reported. In the Islamic Republic of Iran, cereal production was estimated to be well below average .

South Africa flooding
From 9-20 June, the Eastern Cape was badly affected by flooding resulting from a storm. Heavy snow also fell at higher elevations. At least 103 deaths were attributed to the flooding and thousands were displaced .



Coastal & Marine Ecoystems

Rising temperatures heighten the risk of irreversible loss of marine and coastal ecosystems, including seagrass meadows and kelp forest. Coral reefs are especially vulnerable to climate change. They are projected to lose between 70 and 90% of their former coverage area at 1.5 °C of warming and over 99% at 2 °C.

What can we do?

The climate is changing in unprecedented ways, but there are still many options to alliviate the impacts, through both mitigation and adaptation.

Adaptation

As extreme weather continues, predictions must go beyond what the weather will be to include what the weather will do. Early Warning Systems allow people to know hazardous weather is on its way, and informs how governments, communities and individuals can act to minimize the impending impacts. However, one-third of the world’s people, mainly in least developed countries and small island developing states, are still not covered by early warning systems. To face this challenge, UN Secretary-General António Guterres has tasked the World Meteorological Organization and the Office for Disaster Risk Reduction to lead the effort to ensure every person on Earth is protected by early warning systems within five years. Find out more here. However, even if adaptation is improved, the climate will continue to change unless the underlying drivers are addressed. According to the IPCC, current policies as stated in Nationally Determined Contributions (NDCs) are not enough. Without immediate and deep greenhouse gases emissions reductions across all sectors and regions, it will be impossible to keep warming below 1.5° C.

Mitigation

It is therefore urgent to mitigate, or reduce, greenhouse gas emissions from fossil fuels wherever possible. Transitioning to renewable energy sources is a critically important part of reducing emissions. Fortunately, generation of renewables has grown considerably. In 2024, global renewable electricity capacity additions grew 22% to reach nearly 685 GW – a new all-time high. According to the International Energy Agency , 2025 is expected to be another record year, with capacity additions reaching over 750 GW. However, although global renewable power capacity is expected to reach 2.6 times its 2022 level by 2030, it will still fall short of the COP28 tripling pledge.

Climate finance is also on the rise. On average, annual investments increased by 26% between 2021 and 2023. By comparison, the compound annual growth rate between 2018 and 2020 was 8%. At the current rate, meeting USD 6 trillion—the most conservative estimate of required annual climate investment—may be reachable by 2028. However, renewable energy sources and climate finance are not the only solution. There are ways for everyone to take their part.


What will you do?


Time for one last quiz! Your feedback is important to us and helps us improve.


WMO uses datasets developed and maintained by the United States National Oceanic and Atmospheric Administration, NASA’s Goddard Institute for Space Studies, and the United Kingdom’s Met Office Hadley Centre and the University of East Anglia’s Climatic Research Unit in the United Kingdom. It also uses reanalysis datasets from the European Centre for Medium Range Weather Forecasts and its Copernicus Climate Change Service, and the Japan Meteorological Agency. This method combines millions of meteorological and marine observations, including from satellites, with models to produce a complete reanalysis of the atmosphere. The combination of observations with models makes it possible to estimate temperatures at any time and in any place across the globe, even in data-sparse areas such as the polar regions. Internationally recognized datasets are used for all other key climate indicators. Full details are available in the State of the Global Climate report .

NASA, UNEP, WMO.