Virtually certain that 2023 will be warmest year: WMO
United Nation secretary-general Antonio Guterres said that record global heating should send shivers down the spines of world leaders
It is virtually certain that 2023 will be the warmest year in the 174-year observational record surpassing the previous joint warmest years, 2016 at around 1.29°C above the 1850–1900 average, and 2020 at 1.27°C, according to the World Meteorological Organisation (WMO)’s provisional State of the Global Climate report based on the data until October. The difference between 2023, 2016, and 2020 is such that the final two months are very unlikely to affect the ranking.

The temperature until October was about 1.40°C above the pre-industrial 1850-1900 baseline.The Paris Agreement sets long-term goals to guide nations to substantially reduce global greenhouse gas emissions to limit the global temperature increase in this century to 2°C while pursuing efforts to limit the increase even further to 1.5°C to avoid or reduce adverse impacts and related losses and damages.
That a month or months exceeds the 1.5°C limit does not mean it will permanently exceed the level specified in the agreement. But scientists have flagged that severe warming this year will have widespread repercussions.
The WMO report, which was published to inform negotiations at the UN Climate Summit (COP28) that began in Dubai on Thursday, combines input from National Meteorological and Hydrological Services, regional climate centres, UN partners, and climate scientists. The temperature figures are a consolidation of six leading international datasets.
The final State of the Global Climate 2023 report, along with regional reports, will be published in the first half of 2024. The provisional report said record monthly global temperatures have been observed for the ocean – from April through to October – and, starting slightly later, the land – from July through to October.
The past nine years, from 2015 to 2023, were the warmest on record. “The warming El Niño event, which emerged during the Northern Hemisphere spring of 2023 and developed rapidly during summer, is likely to further fuel the heat in 2024 because El Niño typically has the greatest impact on global temperatures after it peaks,” the report said. Greenhouse gas levels were also at a record high in 2022 and continued to increase this year.
WMO secretary-general Petteri Taalas said it is a deafening cacophony of broken records. “These are more than just statistics. We risk losing the race to save our glaciers and to rein in sea level rise. We cannot return to the climate of the 20th century, but we must act now to limit the risks of an increasingly inhospitable climate in this and the coming centuries.”
UN secretary-general Antonio Guterres said record global heating should send shivers down the spines of world leaders. “And it should trigger them to act.” He added they have a road map to limit the rise in global temperature to 1.5°C and avoid the worst of climate chaos. “But we need leaders to fire the starting gun at COP28 in a race to keep the 1.5 degree limit alive: By setting clear expectations for the next round of climate action plans and committing to the partnerships and finance to make them possible; by committing to triple renewables and double energy efficiency; and committing to phase out fossil fuels, with a clear time frame aligned to the 1.5-degree limit.” He called for going further and faster in protecting people from climate chaos.
Carbon dioxide (CO2) levels are 50% higher than in the pre-industrial era, trapping heat in the atmosphere. The long lifetime of CO2 means that temperatures will continue to rise for many years to come, the WMO said. The rate of sea level rise from 2013-2022 is more than twice the rate of the first decade of the satellite record (1993-2002) because of continued ocean warming and melting of glaciers.
The maximum Antarctic sea-ice extent for the year was the lowest on record. Glaciers in North America and Europe once again suffered an extreme melt season. Swiss glaciers have lost about 10% of their remaining volume in the past two years, the report said.
Extreme weather and climate events, including floods, tropical cyclones, extreme heat and drought, and associated wildfires, had major impacts on all continents.
Flooding associated with extreme rainfall from Mediterranean Cyclone Daniel affected Greece, Bulgaria, Türkiye, and Libya with a particularly heavy loss of life in Libya in September. Tropical Cyclone Freddy in February and March was one of the world’s longest-lived tropical cyclones with major impacts on Madagascar, Mozambique, and Malawi. Tropical Cyclone Mocha in May was one of the most intense cyclones ever in the Bay of Bengal.
Some of the most significant extreme heat events were in Southern Europe and North Africa, especially in the second half of July where severe and exceptionally persistent heat occurred. Temperatures in Italy reached 48.2°C, and record-high temperatures were reported in Tunis 49.0 °C, Agadir (Morocco) 50.4 °C and Algiers (Algeria) 49.2 °C.
Canada’s wildfire season was well beyond any previously recorded. Five consecutive seasons of drought in the Greater Horn of Africa were followed by floods, triggering even more displacements. The drought reduced the capacity of the soil to absorb water, which increased flood risk.
Long-term drought intensified in many parts of Central America and South America.
Climate Action Network International global political strategy head Harjeet Singh said the WMO report serves as a grim harbinger, highlighting the irreversible damage inflicted on glaciers, sea levels, and the very essence of the global climate system. “This warning is one we cannot afford to overlook, as the urgency for action resonates now louder than ever. The turmoil caused by record-high temperatures and catastrophic climate impacts is intrinsically linked to the unprecedented surge in greenhouse gases, a direct consequence of rampant fossil fuel use.”
Singh said the world needs immediate and audacious action at the COP28— a definitive road map and timeline for a fair and equitable phase-out of coal, oil, and gas. “It is indisputable that wealthier nations, bearing historical responsibility, must lead the way in decisively shifting from their reliance on fossil fuels to embracing renewable energy sources. Furthermore, they have a crucial role in providing financial support to developing nations, where millions not only face poverty and inadequate access to energy but are also being battered by escalating climate disasters.”
