2023 wasn't just the hottest year on record by far, it also saw record glacier loss, sea level rise, ocean heat and sea ice loss, says World Meteorological Organization report.

Marine heatwaves occurred in many parts of the world in 2023

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Not only was 2023 the hottest year ever recorded, many other key indicators of global heating, such as sea level rise, ocean heat, Antarctic sea ice loss and glacier retreat, also smashed records, according to the World Meteorological Organization’s (WMO) latest State of the Global Climate report.

“Never have we been so close – albeit on a temporary basis at the moment – to the 1.5°C lower limit of the Paris Agreement on climate change,” the secretary-general of the WMO, Celeste Saulo, said in a press release. “The WMO community is sounding the Red Alert to the world.”

A set of glaciers around the world that are monitored to indicate what is happening with all glaciers had the largest loss of ice since records began in 1950, according to preliminary data. The most extreme melting was in Europe and western North America.

The rate of sea level rise has more than doubled since satellite monitoring began in 1993. The rate of global mean sea level rise between 2014 and 2023 was more than twice the rate between 1993 and 2002.

This is due to the thermal expansion of the oceans as they heat up, as well as the melting of glaciers and ice sheets. The overall heat content of the oceans hit a new high in 2023, and the rate of warming has been increasing over the past two decades.

On average, on any one day in 2023 nearly a third of the global ocean was experiencing a marine heatwave. More than 90 per cent experienced heatwave conditions during the year.

At the end of 2023 there was an extreme marine heatwave across the North Atlantic, with water temperatures 3°C above average. Recent studies show marine heatwaves are causing major ecosystem changes and may have caused thousands of whales to starve to death.

Antarctic sea ice extent was by far the lowest on record, with the maximum extent at the end of the southern hemisphere winter 1 million square kilometres below the previous record low. That area is greater than that of France and Germany combined.

Heatwaves, floods, droughts, wildfires and tropical cyclones made worse by global heating also affected the lives of millions and caused economic losses running into the billions of dollars, the WMO report says.

For instance, Hurricane Otis intensified from a tropical storm to a Category 5 hurricane in less than a day. It killed more than 50 people in Mexico and caused up to $16 billion in damage, according to a US National Hurricane Center report.

Overall, 2023 was the warmest year on record, with the global average surface temperature 1.45°C above the preindustrial baseline, the WMO report confirms.

So far 2024 has been even hotter than than 2023, with January and February setting new records according to the EU’s Copernicus climate monitoring service.