This year is on track to be the hottest on record, as warming "temporarily hits" 1.5°C above pre-industrial levels, the World Meteorological Organisation (WMO) said today.
The WMO based its report on six international datasets. EU earth-monitoring service Copernicus — one of the services that WMO uses — said last week that 2024 was "virtually certain" to be the hottest year on record.
The global average temperature in January-September was 1.54°C above pre-industrial levels, the WMO found. The Paris climate agreement seeks to limit global warming to "well below" 2°C above pre-industrial levels, and preferably to 1.5°C. The past 10 years, from 2015-24, have been the warmest on record, the WMO said.
But "one or more individual years exceeding 1.5°C does not necessarily mean that [the Paris Agreement's 1.5°C goal] is out of reach", the WMO said. Although the Paris accord does not give a specific timeframe, the breaching of warming levels "should be understood as an exceedance over an extended period, typically decades or longer", it added.
An initial indication from a WMO-established team suggests that long-term global warming is "likely to be about 1.3°C compared to the 1850-1900 [pre-industrial] baseline", the organisation said.
Even so, "every fraction of a degree of warming matters… every additional increment of global warming increases climate extremes, impacts and risks," WMO secretary-general Celeste Saulo said.
Ocean warming rates "show a particularly strong increase in the past two decades", the report found. Ocean heat content in 2023 was the highest recorded, while data show that "2024 has continued at comparable levels", it added. Oceans absorbed around 3.1mn TWh/yr of heat in 2005-23. Of the energy that accumulates in the earth's system, around 90pc is stored in the ocean, so its warming is expected to continue. This is "irreversible on centennial to millennial timescales", the WMO said.
The rise in global temperature is "turbo-charged by ever-increasing greenhouse gas (GHG) levels in the atmosphere", the WMO said. Concentrations of the three key GHGs — CO2, methane and nitrous oxide — reached record high observed levels in 2023 and measurements suggest that they will be higher in 2024, the WMO said. Levels of CO2 stood at 420 parts per million in 2023 — 51pc above pre-industrial levels — and methane at 1,934 parts per billion, 165pc higher than pre-industrial levels, the organisation said.
The report was released on the first day of the UN Cop 29 climate summit, which is set to run until 22 November in Baku, Azerbaijan.
