Last updated August 1, 2018 at 10:18 am
Chowing down on fish is more climate-friendly than getting stuck into a beef burger.
Greenhouse gas emissions associated with commercial fishing around the globe are increasing, but they are still way below those produced by lamb or beef farming, research by scientists from Tasmania’s Institute for Marine and Antarctic Studies (IMAS) and Canada’s University of British Columbia has found.
The paper, published in the journal Nature Climate Change, represents the first time emissions from fishing and farming have been reliably compared.
Despite the fact that food production accounts for 25 per cent of anthropogenic greenhouse gas production, the contribution made by commercial fishing has been unclear. Limited case studies meant that the industry was either excluded from assessments, or accounted for by only generalised estimates.
Now, however, a team led by Robert Parker – formerly of IMAS and now in Canada – has quantified the fuel usage for the global fishing fleet from 1990 to 2011, and calculated the greenhouse gas emissions that resulted.
Over the period, emissions grew by a hefty 28 per cent without a corresponding increase in harvest – the result, Parker and colleagues say, of a global shift towards more fuel-intensive crustacean-focussed fisheries.
Nevertheless, kilogram for kilogram, fishing remained extremely lean in terms of greenhouse production compared to land-based meat growing.
In 2011, global fisheries used 40 billion litres of fuel and produced 179 million tonnes of carbon-dioxide-equivalent greenhouse gases – just 4 per cent of the total emitted by the food sector.
The researchers found that in energy terms Australian fisheries were among the most expensive in the world.
“Australian fishers target proportionately more high-value crustaceans like rock lobsters and prawns, which are among the world’s most carbon-intensive fisheries on a per kilo basis,” says co-author Caleb Gardner.
“As a result, on average the Australian fishing industry emits 5.2 kilos of carbon for each kilo of fish caught. This contrasts with the US, where each kilo of fish landed cost 1.6 kilos of carbon, and South America, where just one kilo of carbon is emitted for each kilo of fish due to high volumes of anchovies trawled off Peru.”
Even at the high end, however, fish climate costs are much lower than those associated with beef and lamb, which produce between 50 and 750 kilograms of carbon per kilogram.
The researchers suggest that food-related global greenhouse gas emissions could be reduced through introducing a higher proportion of fish into human diets, and by redirecting fish harvests currently used for industrial purposes to the world’s dinner tables.