Legally binding targets to reduce greenhouse gas emissions to net zero in NI should not include methane, a climate change expert has recommended.

Lord Deben, who chairs the UK government’s Climate Change Committee (CCC), has suggested that MLAs at Stormont “could credibly set a net zero carbon dioxide target for 2050”.

“It would be an ambitious target that demonstrates NI’s commitment to the UK net zero, and it has a sound evidentiary basis,” he told the Irish Farmers Journal.

This approach would mean setting a separate, lower target for methane, the greenhouse gas that is emitted by ruminant animals. Two-thirds of emissions from NI agriculture are currently attributed to methane.

A similar approach has been taken to climate change legislation in New Zealand, where methane must reduce by between 24% and 47% by 2050 (compared to 2017 levels), but all other greenhouse gases must fall to net zero over the same time frame.

The logic for splitting emissions targets surrounds the length of time that different greenhouse gases stay in the atmosphere.

Methane breaks down after 10 to 12 years, but carbon dioxide, which comes from burning fossil fuels, accumulates and has a warming effect for centuries. It means a small cut in methane has the same effect on global temperatures as a much bigger reduction in carbon dioxide.

A private member’s bill on climate change which is currently making its way through Stormont includes the headline target to cut all greenhouse gases to net zero by 2045.

Rethink

However, Lord Deben remains openly critical of this target and is urging MLAs to rethink their approach to lowering emissions in NI.

“My committee’s assessment is that a net zero target covering all greenhouse gases cannot credibly be set for NI,” he said.