The carbon footprint of food

Climate change — caused by greenhouse gas emissions — is one of the largest threats to the planet and our ocean ecosystems. Each one of us can reduce our own carbon footprint by making smart choices when it comes to transportation, energy use, consumer habits and what we eat. 

It takes a lot of fuel to grow, package and transport food around the world, which generates carbon dioxide and other greenhouse gases. In fact, our food production system is one of the largest sources of greenhouse gas emissions — contributing 20–30 percent of the global carbon footprint.

Seafood can be a low carbon option

Choosing seafood over other animal products can be one way to lower your carbon footprint. On average, seafood generates less carbon per unit of protein than beef and pork, and has a carbon footprint similar to poultry. But not all seafood is the same. 

• Seafood products vary in the amount of emissions produced. It depends on the type of fish, whether it was wild-caught or farmed and the methods used to catch or farm it. Small pelagics, like sardines or anchovies, provide large amounts of protein and have a small carbon footprint. Others, like crab, shrimp and lobster, tend to have a larger carbon footprint, even as high as some terrestrial animals. 
• You can reduce your personal carbon footprint. Choose seafood with a low carbon footprint like farmed mussels, clams, sardines or anchovies over beef, lamb or higher emission seafoods. 
• Consider other environmental impacts when making dietary choices. While some seafood products may have low carbon footprints, it is important to also consider any negative impacts to habitats, fish stocks and other wildlife as a result of fishing or farming methods.

As our population — and the demand for seafood — continues to grow, it will be increasingly important for fisheries and aquaculture operations to reduce their contribution to global emissions.

Wild-caught seafood

Fuel use

In wild-caught fisheries, the largest contributor to greenhouse gas emissions is the fuel used by diesel-powered fishing vessels. Fuel usage varies significantly depending on what seafood product is being caught and the fishing method used.

Crustaceans like crab, lobster or shrimp are very fuel intensive to catch. Fishermen must motor from trap to trap or drag heavy dredges along the seafloor — both practices burn up a lot of fuel. In comparison, fishermen can set a single purse seine around a school of anchovies or mackerel, and land thousands at a time.

Fishermen can also reduce their fuel use by focusing their efforts on healthy, abundant stocks. When populations become overfished, fishermen must travel farther and longer to catch the same number of fish.

Refrigeration

After fuel, the use of hydrochlorofluorocarbon (HCFC) refrigerants by fishing boats make up the next largest source of emissions in wild-caught fisheries. These chemicals are powerful greenhouse gases, which trap heat within the Earth’s atmosphere and contribute to global climate change.

There are now refrigerants with low global warming impact available for new refrigeration systems, but it is not feasible to retrofit most existing systems. The Montreal Protocol has established the goal of phasing out all HCFCs by 2050. Fishing vessels should aim to minimize the use of these refrigerants and, if possible, replace them with more environmentally-friendly refrigerants.

Aquaculture

Feed production

Most animals raised in aquaculture operations need to be fed. Feed can include fishmeal or fish oil, agricultural products like grains and soy, and more. The growing, harvesting, processing and transporting of these materials to create feed products creates carbon emissions. In aquaculture, in particular, operations that use marine net pens and floating cages, the production of feed is the main source of emissions.

To reduce the emissions produced by aquaculture, the industry continues to improve feed conversion ratios — a measure of how much feed is needed to produce 1 kilogram of live fish. When animals convert food to body mass more efficiently, farmers can use less feed, helping to lower their farm’s carbon footprint. Learn more about improving feed in aquaculture operations.

 Energy use

Land-based aquaculture systems must use energy to circulate water, regulate temperatures and power aeration systems. These systems are typically run on electricity from fossil fuel sources and contribute to the carbon emissions of aquaculture operations. These emissions can be reduced by powering farms with renewable energy.

All seafood

Transportation of fish

Once seafood products reach the dock or leave the farm, they are processed, packaged and distributed. It’s not uncommon for many seafood items we eat to travel around the world before arriving on our plate. This long-distance transportation — especially if by plane — adds to the carbon footprint of seafood. Transporting seafood by ocean freighter, rail or road results in significantly lower carbon emissions compared to air transportation. 

Adaptive management 

Many wild fish and shellfish populations are facing rising ocean temperatures and changing ocean chemistry driven by carbon emissions. Some populations are in decline, some will move to cooler, more hospitable waters, and others may thrive in the new conditions. These changes will likely affect the amount and composition of global fisheries and aquaculture harvests.

To preserve healthy and abundant populations in a changing ocean, regulators will need innovative, adaptive and ecosystem-based management plans that take changing ocean conditions into account. 

The Pacific Northwest region of the U.S. has been home to a thriving shellfish industry for generations. In recent years, changes in oceanic conditions due to carbon emissions have resulted in massive die offs at shellfish hatcheries that provide aquaculture facilities with their animals. Today, scientists, governments and the seafood industry are working together to develop monitoring systems that quickly detect environmental changes and new ways to maintain the broodstock. These efforts will sustain a thriving shellfish industry and the coastal communities that rely upon it.