The world just had the hottest week on record, according to preliminary data. It follows the hottest June on record, with unprecedented sea surface temperatures and record low Antarctic sea ice extent.
The record-breaking temperatures on land and in the ocean have potentially devastating impacts on ecosystems and the environment. They highlight the far-reaching changes taking place in Earth's system as a result of human-induced climate change.
The El Niño event, now in the early stages of development, is expected to turn up the heat even more both on land and in the oceans, and lead to more extreme temperatures and marine heatwaves.
According to provisional reanalysis data from the Japan Meteorological Agency, the average global temperature on 7 July was 17.24 degrees Celsius. This is 0.3°C above the previous record of 16.94 °C on 16 August 2016 - a strong El Niño year.
The Japanese reanalysis data is not yet confirmed. But it is consistent with preliminary data from the Copernicus ECMWF ERA5 dataset.
Comparisons of daily global mean temperature are typically only available from combine observations from satellites etc with computer model simulations, into datasets called reanalyses. WMO uses a combination of reanalysis datasets with global observations from land surface stations and ships for its State of the Climate reports and to assess global temperatures.
"The various reanalysis datasets produced by different centres are consistent with each other. However it is premature to assess what that represents in terms of daily global temperature extremes on land based on actual observations which need a rigorous quality control process , as WMO does for its global state of the climate reports. Nevertheless, these provisional records provides another piece of evidence of the global climate pattern shifts due to climate change and the evolving El Niño episode," says Dr Omar Baddour, chief of climate monitoring at WMO.
Hottest June
A report from the European Union's Copernicus Climate Change Service - a close collaborator with the World Meteorological Organization - showed that June 2023 was just over 0.5°C above the 1991-2020 average, smashing the previous record of June 2019, according to the Copernicus Climate Change Service, implemented by the European Centre for Medium-Range Weather Forecasting. North Atlantic sea surface temperatures were "off the charts," it said.
Global sea surface temperatures were at record high for the time of the year both in May and June. This comes with a cost. It will impact fisheries distribution and the ocean circulation in general, with knock-on effects on the climate. It is not only the surface temperature, but the whole ocean is becoming warmer and absorbing energy that will remain there for hundreds of years. Alarm bells are ringing especially loudly because of the unprecedented sea surface temperatures in the North Atlantic.
Extreme marine heatwaves were observed around Ireland, the United Kingdom and in the Baltic Sea.
The heat in the North Atlantic is caused by by a combination of short-term anomalous circulation in the atmosphere and longer-term changes in the ocean, according to the assessment from Copernicus Climate Change Service. It is not believed to be linked to El Niño, which is only just becoming established in the tropical Pacific and is expected to influence temperatures later in the year and into 2024.
Temperature records:
Record June temperatures were experienced across northwest Europe, according to Copernicus. Parts of Canada, the United States, Mexico, Asia, and eastern Australia were significantly warmer than normal.
It was cooler than normal over western Australia, the western United States, and western Russia.
Sea ice highlights
Antarctic sea ice reached its lowest extent for June since satellite observations began, at 17% below average, breaking the previous June record by a substantial margin.
Throughout the month, the daily Antarctic sea ice extent remained at unprecedented low values for the time of year.
Arctic sea ice extent was slightly below average but well above the June values from the past eight years.
Hydrological highlights
June 2023 was drier than average over much of north America, conditions which favoured and sustained severe wildfires. It was also drier in Russia, the Horn of Africa, most of southern Africa, South America, and regions of Australia, according to Copernicus Climate Change Service.
It was wetter than average over most of southern Europe, western Iceland and north-western Russia, with heavy precipitation leading to floods.
Drier-than-average conditions established over a large west-to-east band across central and eastern Europe and Scandinavia, as well as over the western coast of the Black Sea.
Extratropical wetter-than-average regions included western north America, regions of south-western Asia, Japan, South Africa, Brazil, Chile, New Zealand, and a large region of Australia; Japan and Pakistan were hit by typhoon Mawar and cyclone Biparjoy, respectively.
