According to the WMO, atmospheric carbon dioxide (CO₂) concentrations reached 420.0 ppm in 2023, with real-time data indicating further increases in 2024. These levels represent 151% of pre-industrial CO₂ concentrations, marking the highest atmospheric greenhouse gas levels in 800,000 years. Methane (CH₄) and nitrous oxide (N₂O) levels also reached new records, at 1,934 ppb and 336.9 ppb, respectively.
Moreover, ocean heat content soared to its highest level in the 65-year observational record, continuing an alarming eight-year streak of record-setting ocean warming. The rate of ocean warming from 2005–2024 is now more than double that observed between 1960–2005, amplifying concerns about long-term energy imbalance in Earth’s systems.
Global mean sea level hit a record high in 2024, rising at an annual rate of 4.7 mm between 2015–2024, more than twice the rate seen from 1993–2002. The implications are profound: coastal cities and ecosystems face escalating risks of flooding, erosion, and infrastructure damage. At the same time, glacier mass loss from 2021/2022 to 2023/2024 marked the most negative three-year balance on record, with regions like Norway, Sweden, and the tropical Andes experiencing severe melt.
Additionally, the Antarctic sea ice extent reached its second-lowest maximum and minimum levels ever recorded, continuing a disturbing trend. Arctic sea ice fared no better, with 2024 logging the seventh-lowest minimum extent, underscoring rapid cryosphere degradation.
The report outlines record-breaking displacement due to climate disasters, with 2024 experiencing the highest number of new displacements since 2008. Events such as Tropical Cyclone Chido in Mozambique and Hurricanes Helene and Milton in the United States caused tens of billions in economic damage and hundreds of fatalities. Meanwhile, devastating droughts in Southern Africa, wildfires in Chile and Canada, and heatwaves in Saudi Arabia have further strained infrastructure and food systems.
The compounded effects of these disasters, combined with intensifying food insecurity in 18 countries, illustrate the urgent need for resilient infrastructure, early warning systems, and comprehensive climate adaptation strategies. Yet, only half of all nations have multi-hazard early warning systems in place, a statistic the WMO highlights as critical to address.
While a single year breaching the 1.5°C mark does not signal a permanent overshoot, the WMO emphasizes that every fraction of a degree matters. Current estimates place long-term global warming between 1.34°C and 1.41°C, leaving minimal margin before the Paris Agreement’s temperature goal is breached on a sustained basis. Notably, factors such as El Niño, reduced aerosol pollution, and volcanic activity contributed to the exceptional warmth in 2023–2024, but anthropogenic greenhouse gas emissions remain the dominant driver.
The report urges accelerated investment in National Meteorological and Hydrological Services, alongside global commitments to reduce emissions, protect ecosystems, and strengthen disaster resilience. With ocean acidification, biodiversity loss, and displacement on the rise, the findings serve as a rallying cry for policymakers, businesses, and civil society to act decisively and collaboratively.
Download the full State of the Global Climate 2024 report from the World Meteorological Organization.
