Greenhouse gas emissions increased by 4.7 per cent in 2021 compared to the previous year.
Analysis from the Environmental Protection Agency found the energy industry sector as showing the biggest increase - up 17.6 per cent in 2021.
That's driven by what it says is a tripling of coal and oil use in electricity generation.
Transport emissions increased by 6.1 per cent as COVID-19 restrictions lifted, while residential greenhouse gas emissions fell by 4.9 per cent in 2021.
Mary Francis Rochford of the EPA's Climate Change Programme said there are a number of reasons why the figure has risen.