It was the hottest June on record, unprecedented North Atlantic warmth, record low Antarctic sea ice

The world just had the hottest June on record, with unprecedented sea surface temperatures and record low Antarctic sea ice extent, according to a new report.

The report from the European Union’s Copernicus Climate Change Service – a close  collaborator with the World Meteorological Organization – showed the far-reaching changes taking place in Earth’s system as a result of human-induced climate change.

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.

The heat continues into July – traditionally the hottest month of the year. According to preliminary data from the Copernicus ECMWF ERA5 dataset, the global average 2 meter temperature reached an all-time high of 16.88° C on 3 July, breaking the previous daily record of 16.80°C from August 2016.

“The exceptional warmth in June and at the start of July occurred at the onset of the development of El Niño, which is expected to further fuel the heat both on land and in the oceans and lead to more extreme temperatures and marine heatwaves,” said Prof. Chris Hewitt, WMO Director of Climate Services.

“We are in uncharted territory and we can expect more records to fall as El Niño develops further and these impacts will extend into 2024,” he said. “This is worrying news for the planet,” he 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, “  said Prof. Hewitt.

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 linked to El Niño, which develops in the tropical Pacific.  

According to Carlo Buontempo, Director of the Copernicus Climate Change Service: "These exceptional conditions in the north Atlantic highlight the complexity of the Earth system, and remind us of the importance of monitoring the global climate in near real time. The interplay between local and global variability alongside the climate trends is essential to better manage risks and design efficient adaptation policies."

Temperature records:

The heat extended into the early days of July. According to preliminary data from the Copernicus ECMWF ERA5 dataset, the global average 2 meter temperature reached 16.88° C on 3 July, breaking the previous record of 16.80°C from August 2016.

Comparisons of daily global mean temperature are typically only available from reanalyses - these combine observations from satellites etc with computer model simulations. WMO uses a combination of reanalysis with international datasets based on observations from land surface stations and ships for its State of the Climate reports and to assess global temperatures.

“The ECMWF ERA dataset global daily temperature record corroborates with other international reanalysis datasets. 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. 

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