How the food that Singaporeans eat contributes to climate change

[能田]

(Singapore Today Thursday 31 October 2019)

Explainer: How the food that Singaporeans eat contributes to climate change

By Kimberly Lim

If the average diet in Singapore consists of 50 per cent fruits and vegetables, 25 per cent grains

and 25 per cent meats, eggs and seafood, the greenhouse gas emissions per person will reduce

by 16 per cent compared to the present situation.  TODAY file photo

Updated 31 October, 2019

SINGAPORE — If Singapore does not take steps to reduce the emissions of greenhouse gases in relation to the food consumed by its people, the total emissions in this segment will increase by about 19 per cent by 2030 due to population growth, a study found.  

It also found that the best way to cut such food-related emissions is for people living here to consume less meat. 

Another finding: In Singapore, pork is the source of the highest greenhouse gas emissions per capita consumption here, accounting for about 28 per cent of food-related greenhouse gas emissions.

The study was commissioned by investment firm Temasek and done by the Agency for Science, Technology and Research (A*Star) and financial advisory firm Deloitte between April and July this year.

It looked at 13 key food items in Singapore: Beef, mutton, pork, chicken, duck, egg, fish, other seafood, fruits, leafy vegetables, other vegetables, rice and wheat.  

WHY THE STUDY ON SINGAPORE

Read also: Singapore’s greenhouse gas emissions top 50m tonnes: Report

Food contributes up to a third of global GHG emissions which leads to global warming, and Singapore imports more than 90 per cent of its food, which makes the country more susceptible to climate and natural resource risks.

Red meat, beef in particular, has the biggest carbon footprint per kilogramme of protein, but the environmental impact of food is also affected by the source of the food and the consumption patterns of the local population, the report said.

Most existing studies on the impact of food systems are either centred on the United States or Europe and do not consider unique export-import pairs, it added.

Read also: ‘Worse than anyone expected’: Air travel emissions vastly outpace predictions

For example, food that is air-flown significantly raises its environmental impact. And in Singapore’s case, pork, and not beef, has the biggest carbon footprint due to transportation.

The aim of the study was to have a better understanding on the situation here, so that stakeholders such as policymakers, businesses and consumers are able to focus their sustainability efforts to reduce the environmental impact.

Greenhouse gas emissions, energy consumption and water consumption were the three key environmental impact indicators explored in the study for the life cycle of food — from the time it is produced, processed and transported, to it being consumed.

Read also: The Big Read: Taking the climate fight beyond straws and tote bags — individual actions that matter

WHICH MEATS ARE THE WORST CULPRITS

The environmental impact of meats, especially pork, mutton and beef, is the most severe. 

Beef has the highest greenhouse gas emissions per kg due to manure storage that produce methane, a greenhouse gas.

Read also: Trash Talk: The battle of the food waste bulge — why you should throw away less food

The enteric fermentation from cattle — where food that is decomposed and fermented in the digestive tract of cows, sheep and goats — also produce methane as a by-product.

Using a unit of measurement, the study found that beef has the highest greenhouse gas emissions per kg at 24.4. 

This is followed by mutton at 16.4 and pork at 12.0.

Fish is almost half that of pork at 6.3, while leafy vegetables produce the lowest greenhouse gas emissions per kg of all 13 food items studied at just 0.4.

However, when it came to the highest energy consumption per kg due to air transport, intensive indoor housing and manure management systems for livestock, the order slightly is different.  

Pork has the highest energy consumption per kg at 49.4, followed by beef at 42.6.

Mutton is at 32.8 and fish is at 30.3. Again, leafy vegetables has the lowest energy consumption per kg at 1.8. 

The reason why the energy consumption level for beef is lower compared to pork is because Singapore imports mostly grass-fed beef from countries such as Brazil, Australia and New Zealand. 

This means that the cattle spend more time grazing on pastures instead of staying indoors where energy is required for heating, ventilation and producing the grains to feed the cattle.

Other key findings:

• 367kg of food is consumed per capita (per person) a year in Singapore.

• Although red meats represent about 11 per cent of consumption per capita by weight yearly, they contribute about 40 per cent of greenhouse gas emissions.

• While pork accounts for about 6 per cent of food consumed by weight, it accounts for about 28 per cent of food-related greenhouse gas emissions. 

EMISSIONS FROM PRODUCING FOOD

Pork also has the highest amount of annual greenhouse emissions per capita at 266. 

This is followed by chicken at 121 and rice is at 117.

Leafy vegetables are last-placed of the 13 food items, at just 6.0.

However, rice has the highest water consumption per kg (923 litres per kg) compared to beef (872 litres per kg) and pork (840 litres per kg). This is due to the irrigation of the paddy fields during the production stage. 

A significant amount of water is consumed at the production stage to grow livestock feed as well.

EMISSIONS FROM TRANSPORTING FOOD

Air transport is nine times more carbon-intensive per tonne-kilometre than land transport and about 50 times that of sea transport.

Even though chilled air-flown pork, mutton, beef and fish account for only 9 per cent of food consumed here, they contribute to about 65 per cent of the energy used to transport all food items to Singapore.

For frozen food items transported by land or sea, the study found that the distance from the import source does not significantly impact greenhouse gas emissions due to lower emissions by such modes.

IMPACT OF IMPORTING CHILLED, FROZEN AND FRESH MEAT

The study suggested that the energy sources of the exporting country should be considered instead of just the transport distance. 

Certain food items may be sourced from countries further away, which may have cleaner and renewable sources of electricity generation and thus, have a lesser impact on the environment than sourcing from nearby countries that are more dependent on fossil fuels.

For example, greenhouse gas emissions from air transporting chilled pork from Brazil is almost three times the emissions than when it is flown from Australia, due to the longer distance to Singapore. 

However, this is not the case for frozen chicken. 

The emissions during the processing and production stage for Brazil is 15 per cent lower than that of Malaysia, because Brazil has cleaner energy sources for electricity generation using mostly hydropower. 

For chicken meat, fresh chicken has the lowest greenhouse gas emissions and is recommended for its lower environmental impact. Otherwise, frozen Brazilian chicken may be a good alternative.

The study also found that for pork and beef, frozen meat would be more eco-friendly compared to chilled meat. 

This is because chilled meat needs to be air-flown due to its shorter shelf-life and to maintain freshness. 

For chilled or fresh meat, the study added that they should be sourced in countries closer to Singapore as less transportation would be required, thus generating lower greenhouse gas emissions. 

POSSIBLE SCENARIOS BY 2030  

If business were to go on as usual and locally produced food in Singapore remains at below 10 per cent in the year 2030, but the population grows to 6.7 million, the environmental impact would be great, the researchers said.

The per capita greenhouse gas emissions would remain the same as in 2018, but the absolute or total greenhouse gas emissions for food in Singapore would increase by 19 per cent compared to last year, because of population growth. 

So how could things pan out?

Scenario 1: In a “30 by 30” scenario, where Singapore reaches its goal of producing 30 per cent of its nutritional needs locally by 2030, the study found that the per capita greenhouse gas emissions — or emissions per person — will reduce by 3 per cent compared to if business were as usual, because less transport would be required and cleaner energy could be used in Singapore.

However, this may not be enough because emissions will still increase by 16 per cent compared to 2018 due to population growth. 

Scenario 2: The other option is that people adopt an “optimal health” diet which consists of 50 per cent fruits and vegetables, 25 per cent grains (rice and wheat) and 25 per cent meats, eggs and seafood.

Right now, the average diet in Singapore is 46 per cent fruits and vegetables, 26 per cent grains, and 28 per cent meats, eggs and seafood.

With this optimal health diet, the per capita greenhouse gas emissions will reduce by 16 per cent compared to business as usual, due to lower meat consumption.

Absolute emissions would also drop by 1 per cent compared to the 2018 emissions scenario, despite population growth. 

Scenario 3: This would be a combination of the first and second scenarios above. People would maintain a diet of 25 per cent meats, eggs and seafood, but for the meat portions, 25 per cent or 50 per cent of the red meats consumed such as pork, beef, mutton and duck are replaced by “plant-based meats”.

With this, per capita greenhouse gas emissions will be reduced by 21 per cent (25 per cent of red meats replaced) and 26 per cent (50 per cent of red meats replaced) compared to the business-as-usual situation.

Absolute greenhouse gas emissions will fall by 6 per cent and 12 per cent respectively, compared to in 2018, despite population growth.