How seaweed can reduce greenhouse gases

By Alice Clifford via SWNS

Expanding global seaweed farming could reduce global agricultural greenhouse gases by up to 2.6 billion tonnes of CO2 per year, suggests a new study.

Farming seaweed could thus help with food security, biodiversity loss and climate change challenges.

The versatility of seaweed means it can be used as healthy food or as building blocks for products such as plastics.

Scott Spillias, a Ph.D. candidate from the University of Queensland’s School of Earth and Environmental Science, said: “Seaweed has great commercial and environmental potential as a nutritious food and a building block for commercial products including animal feed, plastics, fibers, diesel and ethanol.

“Our study found that expanding seaweed farming could help reduce demand for terrestrial crops and reduce global agricultural greenhouse gas emissions by up to 2.6 billion tonnes of CO2-equivalent per year.”

Researchers mapped the potential of increasing the farming of the 34 commercially important seaweeds from our oceans.

To do this they used the Global Biosphere Management Model.

The model is used to work out how to use land in the best possible way.

They estimated the environmental benefits of a range of scenarios based on land-use changes, greenhouse gas emissions, water and fertilizer use, and projected changes in species presence by 2050.

Mr. Spillias said: “In one scenario where we substituted ten percent of human diets globally with seaweed products, the development of 110 million hectares of land for farming could be prevented.

“We also identified millions of available hectares of ocean within global exclusive economic zones (EEZs), where farming could be developed.

“The largest share of suitable ocean was in the Indonesian EEZ, where up to 114 million hectares is estimated to be suitable for seaweed farming.

“The Australian EEZ also shows great potential and species diversity, with at least 22 commercially viable species and an estimated 75 million hectares of ocean being suitable.”

Exclusive economic zones are areas of the sea in which a sovereign state has special rights regarding the exploration and use of marine resources, including energy production from water and wind.

Many native species of seaweed in Australian waters have not yet been studied from a commercial production perspective, suggesting it may hold a wealth of untapped potential.

Mr. Spillias added: “The way I like to look at this is to think about ancestral versions of everyday crops – like corn and wheat – which were uninspiring, weedy things.

“Through thousands of years of breeding we have developed the staple crops that underpin modern societies and seaweed could very well hold similar potential in the future.”

However, the team is wary that the seaweed solution must be carried out with care to avoid displacing problems from the land to the ocean.

Professor Eve McDonald-Madden, from the school of earth and environmental sciences at the University of Queensland, said: “Our study points out what could be done to address some of the mounting problems of global sustainability facing us, but it can’t be implemented without exercising extreme caution.”

This research was published in Nature Sustainability.