January 2025 was the warmest January globally, according to new data released by the Copernicus Climate Change Service.
Globally, the temperature last month was 0.79C above the 1991-2020 average for January.
Ireland, however, bucked the global trend.
According to Met Éireann data, last month was 0.45C below the most recent 1991-2020 long-term average.
Professor Karen Wiltshire, chair of climate science at Trinity College Dublin, explained that variability between a national temperature average and the global one for a given period is expected.
In Ireland, January was a cool month overall. There were two major weather events last month. Snowfall on the 4-5 January and Storm Éowyn on 23 January.
Storm Éowyn brought hurricane force winds and broke several wind speed records for the country.
Prof Wiltshire said that Storm Éowyn was a “once in a lifetime storm”.
Because it was such a rare event, she says it is not possible to attribute it to the climate crisis.
“It’s impossible to say it had nothing to do with climate change either,” Prof Wiltshire said.
Global heating increases the likelihood and intensity of extreme weather events.
“It’s so important to look at seasonal variances and to observe the changes over the last 100 years,” Prof Wiltshire said.
According to Met Éireann data, Ireland has become 0.7C warmed and 7% wetter over the past 30 years, when compared to the 30-year period 1961-1990.
Prof Wiltshire said that the weather in Ireland has changed within her own lifetime.
“The levels of carbon dioxide in the atmosphere have never ever been so high,” she said.
Human activity such as burning fossil fuels drives global warming. Average global surface temperatures have risen to 1.1C above pre-industrial levels.
2024 was the warmest year on record globally and the first year where global average temperature exceeded 1.5C above pre-industrial levels.
Data from Copernicus shows that the average global surface air temperature was 13.23C in January 2025, that’s 0.79C above the global average for January.
January 2025 was 1.75C above the pre-industrial level.
This makes it the 18th month out of the last 19 for which the global-average surface air temperature was more than 1.5C above the pre-industrial level.
In most European countries, temperature last month was above the 1991-2020 average. However, in Ireland, the United Kingdom, northern France and Iceland they were below average.
Samantha Burgess, Strategic Lead for Climate at European Centre for Medium Range Weather Forecasts said that the temperature data for January 2025 was surprising as it continues the record temperatures observed over the last two years despite the development of La Nina conditions which has a temporary cooling effect on global temperatures.