The World Meteorological Organization (WMO) has just released its all-encompassing report, State of Global Climate 2023, which collates just about all the scientific knowledge we have on climate change from the past year.
And, as you might imagine, it’s chock full of key findings that explain much of what’s happening on our planet as a result of human-induced climate change.
But before you stress about not having enough time to sift through a dense UN report, fear not. We’ve picked out the most interesting and surprising findings, so you don’t have to.
1. Switzerland lost 10 per cent of its glaciers over the last 2 years
Glaciers form in cold mountainous regions as snow compacts into ice. They then flow downhill, very slowly, like rivers of ice, carving and sculpting mountainsides as they go.
They’re crucial parts of ecosystems, as annual summer glacial melts feed rivers, deliver nutrients across the land, and provide drinking water for people around the globe.
According to the WMO’s report, 2022-2023 saw the largest nominal loss of glacial ice on record, driven mostly by losses in North America and Europe. The situation in Switzerland was particularly grim; 10 per cent of its glaciers were lost in the last two years alone.
“The message is pretty simple and clear: warm the planet and ice melts, but to witness the loss of 10 per cent of glacier volume in part of the European Alps in just two years is staggering,” said Prof Jonathan Bamber, director of the Bristol Glaciology Centre.
“If that trend continues then we could see much of the Alps devoid of glaciers in a matter of decades. That is something that few if any of us, would have expected to see happen so rapidly.”
2. On any given day in 2023, a third of the oceans experienced a heatwave
You may have caught the headlines about the record-smashing sea surface temperatures in Florida last year, but ocean warming isn’t confined to the surface.
The report states that “around 90 per cent of the energy that has accumulated in the Earth system since 1971 is stored in the ocean. As energy has accumulated in the ocean, it has warmed and the heat content of the ocean".
In 2023, ocean heat content – measured as the energy absorbed and stored by the top 2,000 metres of the world’s oceans – reached its highest level since observations began. Scientists think that this trend could take centuries, possibly even millennia to reverse.
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Like ice melting, warmer oceans contribute to sea level rises, since the water is physically less dense and so is larger in volume.
The warming oceans, as one might expect, are leading to increasingly frequent marine heatwaves. In 2023, the average daily marine heatwave coverage reached 32 per cent, up from 23 per cent in 2016.
3. The cost of climate inaction could be staggering
Unfortunately, meeting net zero targets and adapting to the costs of climate change is going to cost serious money – the WMO estimates that if we want to stop a 1.5°C rise in temperatures, annual climate finance investments need to grow by more than six times, reaching almost $9 trillion (£7 trillion) by 2030 and a further $10 trillion through to 2050.
But – and this is a big but – they also estimate that the cost of doing nothing will be way higher.
By the report’s reckoning, inaction throughout 2025–2100 will cost a mouthwatering $1,266 trillion (£995 trillion).
Dr David Rippin of the Department of Environment and Geography at the University of York said: “Taking action makes even more sense, given the report’s statement that inaction over climate change will be more costly than acting.
“The time to do this is now, and the mindset should be one of great urgency."
4. Antarctic winter sea ice was 1 million km2 below the previous record
Extreme environments like the poles of our planet are especially vulnerable to the effects of climate change, but this year was off the charts in Antarctica.
The report found that sea ice extent at the South Pole reached a record low for the satellite era in February.
Sea ice levels in Antarctica typically peak around September, but this year the maximum coverage was 1 million km2 below any level ever recorded – that’s equivalent to the area of France and Spain combined.
Senior research fellow at the National Centre for Atmospheric Science, Dr Till Kuhlbrodt described the results as an “outlier”, but maintained that the “climate and weather extremes we have seen in 2023 are markedly beyond anything we have seen before in the instrumental record” and that "these observations are really concerning".
But all is not lost. According to Prof Tina van de Flierdt, head of the Department of Earth Science and Engineering at Imperial College London, “It is important to note that we are not yet locked into this trajectory: we have the opportunity to prevent the loss of the West Antarctic ice sheet by acting now and strongly reducing emissions globally.
“The future is in our hands, and ongoing climate projects and greater use of clean energy sources offer hope for a just and resilient future."
About our experts
Jonathan Bamber is a physicist who uses Earth Observation (EO) data, primarily from satellites but also airborne platforms, to study the cryosphere. He has authored more than 200 refereed scientific publications about the cryosphere and its interaction with the rest of the Earth System, and is recognised by the Institute for Scientific Information as a "highly cited researcher".
David Rippin is a senior lecturer in physical geography at the University of York. He is a glaciologist, and his research interests are focussed on the controls on the dynamics of glaciers and ice sheets, and the use of ground-based and airborne radio-echo sounding (RES) techniques in exploring englacial and subglacial environments.
Till Kuhlbrodt is a senior research fellow at the University of Reading’s Department of Meteorology. He is the model configuration manager for the UK Earth System Model, a project that develops advanced Earth System Models to provide robust scientific knowledge in support of UK and international efforts to combat climate change. His recent paper, “A glimpse into the future: the 2023 ocean temperature and sea-ice extremes in the context of longer-term climate change” was published in the Bulletin of the American Meteorological Society.
Tina van de Flierdt is the Head of the Department of Earth Science and Engineering and Imperial College London. Her research interests include paleoceanography, paleoclimate, chemical oceanography and Pollution, and Antarctic ice sheet history. Her work has been published in distinguished journals including Nature and the Proceedings of the National Academy of Sciences of the United States of America.
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