It is becoming increasingly urgent to reduce greenhouse gas emissions if the Paris Agreement's goal of limiting warming to well below two degrees is to be achieved. A partly overlooked source of emissions from Sweden is the eutrophic coasts.

According to rough estimates, emissions of the powerful greenhouse gas methane from Swedish territorial waters currently amount to 2.5 million tonnes of carbon dioxide equivalents (on a 20-year scale) per year.

“Methane emissions arise when organic material is decomposed in oxygen-free environments”, says Erik Gustafsson, researcher at the Baltic Sea Centre and author of the new policy brief. “Reducing the nutrient input to the Baltic Sea, which causes eutrophication and oxygen deficiency, would therefore most likely reduce these emissions”.

In the policy brief, the researchers also note that more knowledge about coastal greenhouse gas emissions is needed in order to focus the measures correctly. They therefore propose the development of a system for reporting emissions from different coastal environments.

Erik Gustafsson, Stockholm University Baltic Sea Centre. Photo: Niclas Björling.

“This would make it possible to estimate the effects of various disturbances in the marine environment on the climate, and the climate effects of restoring a coastal area”, says Erik Gustafsson. “These emissions could then also be included in national climate reporting and emissions trading.”

Ongoing climate change makes it particularly urgent to implement measures to reduce eutrophication, as warming itself may increase methane emissions.

“Simultaneously, such measures can lead to better water quality and increased biodiversity," says Erik Gustafsson.

Read more

Reducing eutrophication crucial to prevent coastal methane emissions (layouted pdf with illustrations)

Reducing eutrophication crucial to prevent coastal methane emissions (web text version)

Please contact us at ostersjocentrum@su.se to receive a printed version (free of charge).