The last seven years were the world's hottest on record, with global average temperatures 1.2 degrees above pre-industrial levels, according to the latest data from Europe's climate monitoring agency Copernicus. Ireland is on a similar rising trajectory.
The assessment of 2021 by the EU’s Earth Observation Programme confirms carbon dioxide in the atmosphere has also reached record levels and levels of the super-warming methane gas surged “very substantially”, also reaching a new record.
Prof Peter Thorne of Maynooth University, who is Ireland's leading scientist with the UN Intergovernmental Panel on Climate Change, confirmed Ireland's average temperatures and CO2 levels are showing a similar rapidly rising pattern long term – though there is year-on-year variability.
In line with rising temperatures globally, Ireland experienced its warmest autumn on record during 2021, while the year was the 11th in a row with temperatures above the national average, Met Éireann has confirmed. The average temperature in September was 2.3 degrees above average; the average temperature in autumn was 1.8 degrees above average.
Several records were broken in 2021, in particular during summer heatwaves. On July 21st Ireland had its first “tropical night” in 20 years at Valentia Observatory in Kerry, where temperatures overnight did not fall below 20 degrees.
The trends will inevitably translate into more extreme weather events, making events such as the Christmas Day flooding in Wexford much more likely, Prof Thorne said.
Sea-level rise
In addition, long-term threats in the form of sea-level rise were particularly concerning, as the current CO2 and temperature scenario meant Ireland was facing “multi-metre sea-level rise” – though not in his lifetime.
The global rise in greenhouse gas (GHG) concentrations means more heat is being trapped in the atmosphere than ever before, though 2021 only ranked as the fifth hottest year on record because La Niña exerted a cooling influence by bringing cold waters to the surface in the Pacific Ocean.
2021 coincided with extreme weather striking across the Northern Hemisphere while Europe suffered its hottest summer on record and broke its maximum temperature record in Sicily with 48.8 degrees. Wildfires raged in Italy, Greece and Turkey – and extended to the Arctic circle. Severe floods made up to nine times more likely by global heating wreaked havoc in Germany and Belgium.
Prof Thorne, who is a specialist on extreme weather impacts, said the latest Copernicus figures released on Monday are a consequence of a fundamental failure to eliminate use of fossil fuels. Until that happens, continuing increases in GHG emissions and temperature rise would occur – even allowing for short-term variability.
While 2021 and 2020 would see some cooling because of natural La Niña effects, “it doesn’t mean global warming has stopped”, he underlined. The inevitable return of warming El Niño effects would coincide with further increases in overall global temperatures, he predicted.
Trapped
Unless CO2 was removed from the atmosphere, it was going to be trapped for thousands of years there, he added, whereas reducing more short-lived GHGs such as methane could be a quick win. The scenario underlined the case for getting to net-zero emissions as quickly as possible. If not, “we will continue to warm the climate – it’s as simple as that,” Prof Thorne believed.
The Copernicus data shows 21 of the 22 hottest years have come since the year 2000. "The [extreme weather] events in 2021 are a stark reminder of the need to change our ways, take decisive and effective steps toward a sustainable society," said Carlo Buontempo, director of the Copernicus climate service.
Average CO2 levels reached a new record of 414 parts per million (ppm) in 2021. Before the Industrial Revolution and burning of fossil fuels the level was 280 ppm.
Levels of methane gas are also accelerating, with the growth rate in 2021 approximately three times the rate of a decade ago. Methane is emitted through fossil fuel exploitation, cattle and other livestock production, and from wetland processes, though scientists are uncertain about the cause of recent rapid rises.
