2023 was the hottest year in the last 174 years globally

The heat content of the oceans has reached its highest level in the last 65 years

2023 was the hottest year in the last 174 years globally, since there are observation records, clearly surpassing the previous hottest year, 2016. The last nine years, 2015–2023, were even the hottest since there are records. The data is from the report State of the Global Climate2023, from the World Meteorological Organization (WMO), today released by the Portuguese Institute of the Sea and Atmosphere (IPMA).

The report highlights that the average global air temperature in 2023 was 1.45 ± 0.12°C above the 1850–1900 average, very close to the 1.5°C lower limit of the Paris Agreement on climate change.

The document presents a summary of the state of climate indicators in 2023, of which IPMA highlights surface air temperature, surface and ocean surface temperature on a global scale, concentration of greenhouse gases, amount of heat in the oceans , sea level, ocean acidification, Arctic and Antarctic sea ice, Greenland ice sheet, glaciers, snow cover, precipitation and stratospheric ozone, as well as analysis of the main factors of interannual climate variability, including El Niño – Southern Oscillation.

In relation to extreme phenomena, those related to tropical cyclones, wind storms, floods, droughts and extremes of heat and cold stand out.

This report also presents the latest findings on climate-related risks and impacts, including food security and population displacement.

Graph on global temperatures



The following indicators stand out in this report:
Air temperature: 2023 was the hottest year in the last 174 years (observation records), clearly surpassing the previous hottest year, 2016, 1.29 ± 0.12 °C above the 1850–1900 average (Fig. 1). The last nine years, 2015–2023, have been the hottest on record.
• Greenhouse gases: the concentration of the three main greenhouse gases – carbon dioxide, methane and nitrous oxide – reached record levels observed in 2022, the last year for which consolidated global values ​​are available (1984–2022).
Real-time data from specific locations shows that levels of all three greenhouse gases continued to rise in 2023.• Oceans: the heat content of the oceans has reached its highest level in the last 65 years (observational records).
A prolonged period of La Niña from mid-2020 to early 2023 gave way to El Niño conditions that established until September 2023, which contributed to the increase in global mean sea surface temperatures during 2023.

• Average sea level: In 2023, global average sea level reached an all-time high in satellite records (from 1993 to present), reflecting the continued warming of the oceans, as well as the melting of glaciers and ice sheets.
The rate of global mean sea level rise over the last ten years (2014–2023) is more than double the rate of mean sea level rise in the first decade of satellite records (1993–2002).



• Arctic sea ice: The extent of sea ice in the Arctic remains much lower than normal in 2023 (see figure above), with the maximum annual extent and minimum annual extent being respectively the 5th and 6th lowest values ​​since 1979 (beginning of satellite records).
Antarctica also reached a record absolute minimum in the month of February and an all-time low from June to early November.

• Ice cover in Greenland: It was the hottest summer on record at Summit Station, 3.4 °C warmer than the 1991–2020 average and 1.0 °C warmer than the previous record.

• Glaciers: The glaciers of western North America and the European Alps experienced a period of extreme thinning.
In Switzerland, glaciers have lost around 10% of their remaining volume in the last two years.

• Extreme events: extreme weather conditions continued to cause serious socioeconomic impacts.
Extreme heat has affected many parts of the world, wildfires in Hawaii, Canada and Europe have led to loss of life, destruction of homes and large-scale air pollution.
Flooding associated with extreme rainfall from Cyclone Daniel in the Mediterranean affected Greece, Bulgaria, Turkey and Libya, with loss of life in particular in Libya.