Energy related emissions were up 5.4% last year, according to new figures from the Sustainable Energy Authority of Ireland (SEAI).
This comes despite a commitment by Ireland to reduce CO2 emissions by 4.8% per year from 2021- 2025 under the first carbon budget.
Today's Energy Balance data show that emissions are now back at the same level as 2019, after a temporary reduction due to Covid-19-releated restrictions.
The data shows that a rebound in car use after the lifting of Covid-19 restrictions is a significant contributor to Ireland's increased emissions.
Energy demand for transport rose by 8.3% from its significant suppression in 2020.
"While this may be expected, it underlines the urgent requirement for change in the transport sector with a necessary shift to cycling, walking, public transport, and electric vehicles and eliminating unnecessary car journeys," the SEAI said in a statement.
It said increased energy demand, combined with modest delivery of new renewable capacity, and a low-wind year resulted in Ireland’s renewable energy share remaining unchanged since last year, at just 13.6%.
It also said the low wind year resulted in more use of coal and oil in electricity generation to meet requirements, further adding to emissions levels.
"Overall, the Energy Balance shows us that in the first year of our legally binding carbon budgets, we have seen emissions trending in the complete opposite direction of where we need to be," said Margie McCarthy, Director of Research and Policy Insights with SEAI.
"This means we have used a disproportionate amount of our carbon budget in 2021, which results in future years being even more challenging.
"In addition, looking at the early data from 2022, this trend is worryingly continuing," she added.