Ireland's greenhouse gas emissions fell for the first time in 20 years because of the economic downturn, scientists have revealed.
The recession led to an unprecedented drop in carbon dioxide fumes pumped out by cars, factories, power plants and homes - down almost 8% last year.
The Environmental Protection Agency (EPA) said emissions fell in every sector, with farms still the largest CO2 polluters.
But despite the successes, Ireland is still about 5% above its Kyoto targets.
EPA director general Mary Kelly warned that the country should not be using a downturn to keep to its commitments to tackling climate change.
"We should not rely on a recession to meet our targets for the future," she warned.
Dr Kelly said the improvements in CO2 levels should be used to embed fundamental reductions and ultimately meet very stringent European limits for 2020.
"The magnitude of the reduction in Ireland's annual greenhouse gas emissions in 2009 is unprecedented," she said.
"In particular, the 20% cut in emissions from the industry and commercial sector reflects the impact which the severe economic recession is having on industrial output in Ireland."
A breakdown of emissions showed the amount of CO2 from industry and commerce fell by 20%, energy was down by 11%, and transport by 8%. The cement manufacturing business was down 38%, the EPA said.