🌡️ The new annual report "State of the Global Climate 2024" from the World Meteorological Organization (WMO) provides important insights into the current state of our planet. A message stresses that the year 2024 was marked by new records in key climate indicators and highlights the urgent need to step up efforts to combat climate change and strengthen the resilience of societies to extreme weather events.

Key climate indicators

The WMO report looks in detail at several key climate indicators that provide a comprehensive picture of the changing state of the Earth.

• Atmospheric carbon dioxide (CO2) and other greenhouse gases: Concentrations of the main greenhouse gases – carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) – reached their highest levels in 800,000 years in 2023. Real-time data show that these levels continued to rise in 2024. In 2023, the global annual average mole fraction of CO2 reached 420.0 ± 0.1 parts per million (ppm), which is 151 % of the pre-industrial concentration (in 1750). Human-induced increases in CO2 concentrations are the largest driver of climate change, with CO2 contributing about 66 % of the radiative forcing of all long-lived greenhouse gases since 1750. Human activities such as fossil fuel combustion, cement production and land-use change, including deforestation, are the main sources of CO2. It is estimated that 48 % of total human emissions remained in the atmosphere over the period 2014–2023. Increased atmospheric CO2 is associated with risks such as increased greenhouse effect, ocean acidification, variations in crop productivity and food insecurity.
• Global average surface temperature: The year 2024 was the warmest year in the 175-year observational record, with an annual mean global surface temperature of 1.55 °C ± 0.13 °C above the 1850–1900 average. This year surpassed the previous record set in 2023, when the average was 1.45 °C ± 0.12 °C above the same reference period. Each of the last ten years, 2015–2024, was individually the warmest year on record. Exceeding 1.5 °C in a single year does not mean that the long-term temperature goals of the Paris Agreement are unattainable, but it is a wake-up call to increasing risks. The global temperature in 2024 was reinforced by a strong El Niño event that peaked at the beginning of the year. The increase in global mean surface temperature is associated with risks such as decline in agricultural and fisheries yields, displacement, water shortages, conflicts, degradation of built infrastructure, loss of biodiversity and species, global health problems and food insecurity.
• Heat content in the oceans: In 2024, ocean heat content reached its highest level in the 65-year observational record, surpassing the previous record set in 2023. Each year for the past eight years has set a new record for ocean heat content. The rate of ocean warming over the past two decades (2005–2024) is more than double that of 1960–2005. Most of the excess energy in the Earth system (about 90 %) goes into ocean warming. Ocean warming has wide-ranging consequences, such as degradation of marine ecosystems, loss of biodiversity and reduction of the ocean's capacity to absorb carbon. It fuels tropical and subtropical storms and exacerbates the ongoing loss of sea ice in the polar regions. Together with the loss of land ice, it causes sea levels to rise. Associated risks include coral bleaching, deoxygenation, higher ocean stratification and habitat degradation.
• Global average sea level: In 2024, global mean sea level reached a record high in the satellite record (since 1993). The rate of sea level rise over the past 10 years (2015–2024) was more than double that of the first decade of satellite record (1993–2002). The variation in global mean sea level is correlated with the El Niño–Southern Oscillation (ENSO). Ocean warming causes thermal expansion of water and sea level rise. Melting of land ice also contributes to this phenomenon. As ocean warming continues for centuries even if greenhouse gas emissions are stopped, sea level will continue to rise on the same timescale. Changes in sea level have far-reaching effects on coastal areas and communities, leading to loss of coastal ecosystems and services, salinization of groundwater, flooding and damage to coastal infrastructureThese impacts cascade into risks for livelihoods, settlements, health, well-being, food and water security, as well as cultural values.
• Ocean pH (ocean acidification): Ocean surface acidification has continued over the past 39 years, as evidenced by a steady decline in the global average pH of the ocean surface. Although the water remains slightly alkaline (pH above 7), the observed decrease in pH is referred to as ocean acidification. Approximately a quarter of the CO2 emitted by human activities in the decade 2014–2023 was absorbed by the ocean, causing a shift in ocean carbonate chemistry. Changes in pH in the deep ocean are irreversible on timescales of centuries to millennia. Ocean acidification affects marine life, including habitat degradation, biodiversity loss and deterioration of food production from aquaculture and fisheriesIt is associated with risks such as food insecurity, reduced livelihoods, changes in the marine food chain and disruption of marine shell and skeleton formation.
• Glacier mass balance: Glacier mass loss from 2021/2022 to 2023/2024 represents the most negative three-year glacier mass balance on record. Seven of the ten most negative annual glacier mass balances since 1950 have occurred since 2016. Preliminary observations for 2023/2024 indicate another year of extremely negative glacier mass balance globally. Glaciers are formed from snow that compacts into ice and flows down. Ice loss from glaciers contributed about 21 % of the total sea level rise from 1993 to 2018. Human influence is very likely the main cause of global glacier retreat since the 1990s. Glacier mass loss is associated with risks such as water scarcity and pollution, reduced ocean capacity to absorb carbon, changes in global weather patterns, melting of freshwater supplies, landslides, mudslides, avalanches, changes and losses in biodiversity, species extinctions, reduced agricultural yields, loss of tourism, flooding and degradation of built infrastructure.
• Sea ice extent: The minimum daily Arctic sea ice extent in 2024 was the seventh lowest on record (since 1979). All 18 of the lowest minima in Arctic sea ice extent in the satellite record occurred in the past 18 years. The annual minimum and maximum of Antarctic sea ice extent were the second lowest on record. Sea ice extent in both the Arctic and Antarctic was below the 1991–2020 average for the entire annual cycle in 2024. Sea ice is frozen seawater that floats on the surface of the ocean. The long-term downward trend in minimum Arctic sea ice extent from 1979 to 2024 is about 14 % of the 1991–2020 average per decade. Declining sea ice extent is associated with risks such as changes in surface albedo, new transport routes, water pollution, changes and losses in biodiversity, species extinction, resource conflicts, overfishing and hunting, degradation of ecosystems and habitats, and food insecurity.

Climate factor – El Niño–Southern Oscillation (ENSO)

The strong El Niño in 2023/2024 followed three consecutive years of La Niña from late 2020 to early 2023. El Niño conditions stabilized by mid-2023, strengthened by late 2023, and dissipated by the second quarter of 2024. This phenomenon typically temporarily increases global average temperatures. Global temperatures in 2023 and 2024 were warmer than in previous years, which is typical of El Niño conditions. ENSO is one of the most important drivers of interannual and seasonal variability in weather patterns around the world and is associated with changes in the occurrence and distribution of hazards such as heavy rainfall, flooding, drought, heat waves, and cold spells. The transition from El Niño to neutral conditions in 2024 was also likely associated with a temporary decrease in global average sea level.

Global temperature and precipitation patterns in 2024

Most land areas were warmer than the long-term average (1991–2020) in 2024. Record or near-record annual average temperatures were observed over large areas of the tropics, eastern North America, northern Africa and Europe, and southern and eastern Asia. Sea surface temperatures reached record highs in the tropical and North Atlantic, tropical Indian Ocean, parts of the western Pacific, and parts of the Southern Ocean.

In terms of precipitation, drier than average (1991–2020) conditions were observed in many parts of southern Africa, some locations on the West African coast, and along the North African coast. Large parts of South America were also drier than normal. Areas in The Sahel region, parts of central and southern East Africa, and central and western Europe were wetter than normal.

High-impact events

Extreme weather events in 2024 led to the highest number of new displacements recorded in a single year since 2008, affecting significant numbers of people in fragile and conflict-affected areas. Together with the destruction of homes, infrastructure, agricultural land and biodiversity, these events undermine resilience and pose significant risks. The compounding effects of multiple shocks, such as intensifying conflict, drought and high domestic food prices, have led to worsening food crises in 18 countries by mid-2024.

Tropical cyclones were responsible for many of the largest high-impact events in 2024, including Typhoon Yagi in Southeast Asia and Hurricanes Helene and Milton in the United States. In the Southern Hemisphere, Tropical Cyclone Chido hit Mozambique and Malawi, causing significant damage and loss of life.

Afghanistan and neighboring areas affected abnormal cold and flooding, which led to hundreds of deaths and flooding of agricultural land. In Central Africa, it brought abnormally active monsoon widespread flooding, which affected almost every country in the region. Conversely, dry conditions in late 2023 and early 2024 led to significant drought in northwest Africa and many parts of southern Africa, which impacted agriculture and hydroelectric power generation. Chile hit by devastating forest fires with a high number of deaths and damages. In Brazil, they led persistent heavy rainfall leading to flooding with significant losses.

In 2024, there was also many significant heat waves, with many experiencing long periods of heat and breaking records at many stations. Regions affected by heat waves included East Asia, southeastern Europe, the Mediterranean and the Middle East, as well as the southwestern United States. Among the most notable events was a June heat wave in Saudi Arabia, when temperatures near Mecca reached 50 °C.

Global temperature monitoring for the Paris Agreement

Individual years with global average temperatures exceeding 1.5 °C above the 1850–1900 average do not mean that the Paris Agreement goal of “pursuing efforts to limit the temperature increase to 1.5 °C above pre-industrial levels” is unattainable. Global temperatures do not increase smoothly from year to year; in addition to the long-term warming caused by greenhouse gas emissions, there is significant interannual natural climate variability. According to the IPCC definition, climate change refers to change that persists over an extended period of time, typically decades or longer. Therefore, exceeding the 1.5 °C and 2.0 °C warming levels in the Paris Agreement should be understood similarly to exceeding over a longer period. There are different methodologies for monitoring long-term changes in global temperature in relation to the goals of the Paris Agreement, with the best estimates of current global warming (as of 2024) ranging between 1.34 °C and 1.41 °C above the reference period 1850–1900. It is essential to recognize that, regardless of the methodology used, every tenth of a degree of warming matters.

Towards understanding the influencing factors of the global average temperature anomalies in 2023/2024

The record global average surface temperatures in 2023 and 2024 occurred in the context of rising temperatures driven by continued increases in anthropogenic greenhouse gas emissions. However, their specific magnitude has attracted attention. Several other factors may help explain these records: the faster-than-expected onset of solar cycle 25, the evolving impacts of IMO regulations on sulphur content in marine fuel (valid from January 2020), eruption of the Hunga Tonga–Hunga Ha'apai volcano (January 2022) and Decadal declines in aerosol emissions from East AsiaAnomalous patterns of internal variability in Saharan dust over the Atlantic and/or in Antarctic sea ice extent may also have played a role.

WMO's "State of the Global Climate 2024" report confirms ongoing and accelerating changes in key global climate indicators, as they are greenhouse gas concentrations, global temperature, ocean heat, sea level and the state of the cryosphereThese changes have significant environmental and social impacts, which is manifested in frequency and intensity of extreme weather events, as well as in their socio-economic consequences, including mass displacement and food insecurityThe report highlights the need to strengthen early warning systems and invest in national meteorological and hydrological services to build more resilient societies. Given the unprecedented state of the climate in 2024, it is clear that urgent and more ambitious climate action is more than ever crucial for the future of our planet. Spring

Glossary of key terms

• Atmospheric carbon dioxide (CO2): A key greenhouse gas whose concentration in the atmosphere is the main driver of human-caused climate change.
• Global average temperature near the surface: An index of temperature near the Earth's surface, averaged over its entire surface.
• Heat content in the oceans: The rate of excess energy absorbed by the oceans, usually integrated from the surface to a depth of 2000 m.
• Global average sea level: The average height of the ocean surface worldwide, affected by ocean warming (thermal expansion) and melting ice on land.
• Ocean pH: The degree of acidity or alkalinity of ocean water; a decrease in pH is known as ocean acidification.
• Glacier mass balance: The difference between the accumulation of snow and ice on a glacier and the loss of ice through melting and other mechanisms.
• Sea ice extent: The area of ocean with at least 15% of sea ice coverage.
• El Niño–Southern Oscillation (ENSO): A climatic phenomenon characterized by variations in sea surface temperature in the tropical Pacific and changes in atmospheric pressure that significantly affect global weather.
• Radiation exposure: A change in the net energy flow to the Earth system caused by external influences such as greenhouse gases or aerosols.
• Pre-industrial conditions: The period before significant human influence on atmospheric composition, often referred to as 1850–1900 for global temperature and 1750 for greenhouse gases.
• Anomaly: Deviation of the measured value from the average of the basic reference period.
• Zettajoule (ZJ): A unit of energy, equal to 10^21 joules, used to measure large-scale energy changes in the Earth system, such as the heat content of the oceans.
• Paris Agreement: An international agreement under the United Nations Framework Convention on Climate Change that aims to limit global warming.
• IPCC: Intergovernmental Panel on Climate Change, the leading international body for assessing the science of climate change.
• La Nina: A cooler phase of ENSO, characterized by lower than average sea surface temperatures in the eastern tropical Pacific.
• Aerosols: Tiny particles in the atmosphere that can affect climate by scattering and absorbing radiation and influencing cloud formation.
• Meteorological reanalyses: A system using meteorological forecasting models to combine different types of measurements (including satellite measurements) to create consistent datasets on the state of the atmosphere and oceans.
• Tide gauge: An instrument for measuring sea levels along the coast.
• Radar altimeter: An instrument on satellites that measures the height of the sea surface by transmitting and receiving radar signals.