2023 ‘hottest year’ records lowest sea ice, glaciers; 90% ocean experienced heatwave conditions: WMO

Vibha Sharma

Chandigarh, March 20

The fact that 2023 was the hottest year on record that smashed the global temperature record has already been confirmed by the World Meteorological Organization (WMO).

Now, according to the State of Global Climate report, which reconfirms 2023 as the “hottest year on record by clear margin”, on an average day in the year nearly one third of the global ocean remained gripped by a marine heatwave, harming vital ecosystems and food systems.

“Towards the end of 2023, over 90 per cent of the ocean had experienced heatwave conditions at some point during the year. The global set of reference glaciers suffered the largest loss of ice on record (since 1950), driven by extreme melt in both western North America and Europe according to preliminary data,” as per the latest WMO report released ahead of the World Meteorological Day on March 23.

Records were broken for ocean heat, sea level rise, the Antarctic sea ice loss and glacier retreat. The extreme weather undermined socio-economic development. However, the renewable energy transition provides hope, it said.

“Heatwaves, floods, droughts, wildfires and rapidly intensifying tropical cyclones caused misery and mayhem, upending every-day life for millions and inflicting many billions of dollars in economic losses,” according to the WMO State of the Global Climate 2023 report.

2023—the warmest year

With the global average near surface temperature at 1.45 °Celsius (with a margin of uncertainty of ± 0.12 °C) above the pre-industrial baseline, 2023 was the warmest 10-year period on record.

Globally, every month from June to December was record warm for the respective month.

September 2023 was particularly noteworthy, surpassing the previous global record for September by a wide margin (0.46 to 0.54 °C).

The shift from La Niña to El Niño conditions in the middle of 2023 contributed to the rapid rise in temperature from 2022 to 2023.

Global average sea-surface temperatures (SSTs) were at a record high from April onwards, with the records in July, August and September broken by a particularly wide margin.

Ocean heat content reached its highest level in 2023, according to a consolidated analysis of data.

The end of 2023 saw a broad band of severe and extreme marine heatwave across the North Atlantic, with temperatures 3 °C above average.

“Sirens are blaring across all major indicators… Some records aren’t just chart-topping, they’re chart busting. And changes are speeding-up.” said United Nations Secretary-General António Guterres.

“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”, according to WMO Secretary-General Celeste Saulo.

Alarming state of oceans, sea ice, glaciers

The unprecedented ocean warmth, glacier retreat and Antarctic sea ice loss is cause for particular concern, according to the WMO statement.

In 2023, global mean sea level reached a record high in the satellite record (since 1993), reflecting continued ocean warming (thermal expansion) as well as the melting of glaciers and ice sheets.

The rate of global mean sea level rise in the past 10 years (2014–2023) is more than twice the rate of sea level rise in the first decade of the satellite record (1993–2002).

Meanwhile, Antarctic sea-ice extent reached an absolute record low for the satellite era (since 1979) in February 2023 and remained at record low for the time of year from June till early November.

The annual maximum in September was 16.96 million km2, roughly 1.5 million km2 below the 1991–2020 average and 1 million km2 below the previous record low maximum, it said

Arctic sea-ice extent remained well below normal, with the annual maximum and minimum sea ice extent being the fifth and sixth lowest on record respectively.

“There are two principal ice sheets, the Greenland Ice Sheet and the Antarctic Ice Sheet. Combining the two ice sheets, the seven highest melt years on record are all since 2010, and average rates of mass loss increased from 105 Gigatonnes per year from 1992–1996 to 372 Gigatonnes per year from 2016–2020. This is equivalent to about 1 mm per year of global sea level rise attributed to the ice sheets in the latter period.

“The Greenland Ice Sheet continued to lose mass in the hydrological year 2022–2023, it said. Preliminary data for the hydrological year 2022-2023 indicate that the global set of reference glaciers suffered the largest loss of ice on record (1950-2023), driven by extremely negative mass balance in both western North America and Europe.

In Switzerland, glaciers have lost around 10 per cent of their remaining volume in the past two years.

“The climate crisis is the defining challenge that humanity faces and is closely intertwined with the inequality crisis – as witnessed by growing food insecurity and population displacement, and biodiversity loss” Celeste Saulo was quoted as saying in the statement.

Acutely food insecure people double worldwide

As per the WMO statement, the number of people who are acutely food insecure worldwide has more than doubled, from 149 million people before the COVID-19 pandemic to 333 million people in 2023 (in 78 monitored countries by the World Food Programme).

Weather and climate extremes may not be the root cause, but they are aggravating factors.

Weather hazards continued to trigger displacement in 2023, showing how climate shocks undermine resilience and create new protection risks among the most vulnerable populations.

Extreme weather and climate events had major socio-economic impacts on all inhabited continents. These included major floods, tropical cyclones, extreme heat and drought, and associated wildfires.

Renewable energy gives hope

There remains a glimmer of hope and that is renewable energy generation.

Driven by the dynamic forces of solar radiation, wind and the water cycle, renewable energy has surged to the forefront of climate action for its potential to achieve decarbonisation targets, as per WMO.

In 2023, renewable capacity additions increased by almost 50% from 2022, for a total of 510 gigawatts (GW) – the highest rate observed in the past two decades.

This week at the Copenhagen Climate Ministerial climate leaders and ministers from around the world are meeting for the first time since COP28 in Dubai to push for accelerated climate action.

Enhancing countries’ Nationally Determined Contributions (NDCs) ahead of the February 2025 deadline is high on the agenda, as will delivering an ambitious agreement on financing at COP29 to turn national plans into action, says the UN organisation.

The bottom line is “cost of climate inaction is higher than cost of climate action”.