Scientists at the Max Planck Institut and Denmark's Aarhus University found that mussels, freshwater snails and other underwater creatures release nitrous oxide – laughing gas – when nitrate is present in water.
"There's nitrate in water that has been polluted by humans, so the more we pollute, the higher the production of this problematic gas will be," Fanni Aspetsberger from the institute told AFP on Tuesday.
Aspetsberger added that no quantitative data were available, but that it could be "seriously detrimental" to the climate if nitrate pollution continues to rise the way it has over recent years.
Laughing gas is one of many greenhouse gasses that has been released into the atmosphere since industrialisation. Such gasses act as a blanket around the Earth, causing temperatures to rise worldwide.
Rising temperatures have already had disastrous consequences for mankind – including major disruptions to global weather systems – and problems are expected to become worse in the future.
The main reason for global warming though, is the release of another greenhouse gas, carbon dioxide, by the burning of fossil fuels. World leaders aim to strike a new global climate deal in Copenhagen in December.