Ireland's climate budgets do not go far enough, an Oireachtas Committee has heard.

A number of academics have appeared before the Joint Committee on Environment and Climate Action, which is considering Ireland's first Carbon Budgets.

These three budgets establish a national ceiling for the total amount of emissions that can be released, the first of which runs from 2021 - 2025.

Emeritus Professor of Geography John Sweeney of Maynooth University said that there was a requirement for leadership and for Carbon Budgets to be "toughened up".

Professor Barry McMullen of DCU said that faster reductions in the first two Carbon budgets are required.

He pointed out that the Programme for Government commits to an average reduction in total emissions of 7% per year over the period 2021-2030. However, he told members that the Climate Change Advisory Council's proposal would result in a just under 6% reduction per year.

Professor McMullen suggested that 8% per year would be preferable.

He said that he accepted the logic behind the argument that higher reductions are easier to achieve in later years, as new infrastructure will make it more attainable. However, he warned that time doesn't allow for further delay.

Professor McMullen said that the situation wasn't too dissimilar to the pandemic, in that measures which were once unthinkable must become a reality, as the alternative is much worse.

This was a view echoed by Professor John Sweeney of Maynooth University, who told TDs and Senators that further delay wasn't acceptable. Professor Sweeney warned that failure to achieve targets set out in the Paris Agreement could lead to irreversible changes to the global climate system.

"We may alter the circulation of the Atlantic, which Ireland is so dependent on. We may lose the Arctic summer sea ice. We may start the irrevocable melting out of Greenland," he told members.

He called for a reduction in the cattle numbers and said that there needed to be a methane emissions reduction of 3% a year.

Professor Kevin Anderson from the University of Manchester said that the carbon budgets were "political" and "out of touch with the science".

He said that emissions align very closely to income and therefore policies must be tailored to address that. Professor Anderson pointed out that 15% of air passengers in the UK are responsible for 70% of aviation pollution.

People Before Profit's Bríd Smith expressed concern over the reliance on future technologies to help Ireland achieve its carbon reduction targets.