Hot, dry summers; torrential rain causing rivers to burst their banks. These days that is all too familiar. Climate patterns are changing, and the main culprit? CO2 emissions. Primarily due to human activity. Food causes a quarter of global greenhouse gas emissions, so there is an increasing call for people to eat locally grown foods. The idea is that then, at least, CO2 emissions from transportation can be avoided. But, in the Netherlands, does a locally cultivated greenhouse tomato emit less CO2 than one imported from Spain? And what about, say, Spanish versus Peruvian mangoes?
Using statistics, we can tentatively compare a few fruits and vegetables with each other and their country of origin. For that, we use the term CO2eq, a concept that includes greenhouse gases other than carbon dioxide, such as methane or nitrogen oxides (methane is 28 times more potent as a greenhouse gas than CO2). But food obviously has a broader environmental impact than just greenhouse gas emissions. Things like land, water, and crop protection agents usage and soil acidification also play a role. This article will not discuss those.
Foodfootprint
When talking about food's CO2 footprint, we must first distinguish between plant and animal-based. These have significantly different greenhouse gas emissions, far more than, for example, comparing a mango flown in from abroad and one grown in Spain or Spanish versus Dutch-grown cauliflower. That is because methane plays a major role in meat-derived food production.
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The Dutch FoodFootprint website lays out the climate impact (CO2 eq and water consumption) of a portion of some food products, from bread and beverages to meat and fresh produce. A portion is usually 100g for meat and between 100 and 200 g for fruit and vegetables, depending on the product. That is compared to how many kilometers you would have to drive a passenger car or how long your shower would have to be to achieve the same carbon footprint. They get that information from the Netherlands' National Institute for Public Health and the Environment (RIVM). It provides a database on its website about the environmental impact of a range of foods, compiled by means of a Life Cycle Analysis (LCA).
Steak vs cauliflower
Please note: all the data below refer to one kilogram of the relevant food product in a supermarket in the Netherlands; if produce comes from several countries, a weighted average is used. Producing, storing, and transporting a kilogram of eggs emits just under 3 kilos of CO2eq. For chicken, it is 4kg; for cheese, between 6 and 9 kg; for pork, more than 7 kilograms; and for beef, it is around 20 kilos. That differs enormously from fresh produce, whose CO2 equivalence is between 200g and 3.5kg.
Carrots hover at a modest 200g; lettuce, leek, onions, bananas, pineapples, and apples produce 100 grams more; and citrus, grapes, and kiwis clock in at 400g. Stone fruit and melons emit 500g; broccoli, cauliflower, and cucumber fluctuate around 600 grams, while mango and avocado barely reach the 1kg mark, as do tomatoes. Mushrooms, peppers, and courgettes emit just about 2 kilograms. Strawberries top the list at 3.3 kilos.
An article by Hannah Ritchie on the Our World in Data website cites a 2018 Joseph Poore & Thomas Nemecek study. That also shows that fruit, vegetable, and potato consumption is associated with far lower greenhouse gas emissions than that of dairy and meat. However, the figures differ slightly. The study involved 38,700 growers in 119 countries and the emissions relate to the entire chain (land use conversion, cultivation, processing, packaging, transportation, and retail display). Citrus would produce 0.3 CO2eq per kilo of product; apples and carrots 0.4; bananas 0.7; tomatoes 1.4; milk 3; eggs 4.5; chicken 6; pork 7; cheese 21, and beef 60.
Here, you must also note that a portion of dairy or meat is smaller than that of fresh produce. Regardless, you can conclude that eating dairy products, meat, and, of course, (ultra)processed products produces more greenhouse gas emissions than eating fresh fruit and vegetables. For example, in terms of CO2 emissions, consuming 100g of pork is the same as taking an 11 km car trip, while eating a portion of kiwi (80 grams) is equivalent to 500m.
The wait for harmonization
The RIVM did its calculations in 2024. An earlier comparable study in 2019 shows that the environmental impact was considerably higher. That is because the basic data and calculation methods have been updated, explains the RIVM. You can, thus, not rule out that the results will still be subject to change in the future as data collection and calculator methods are refined. Also, not every research institute's analyses include the same elements, which makes it virtually impossible to directly compare the results of different studies. Harmonization in this area will undoubtedly continue.
Within the Corporate Sustainability Reporting Directive framework, large companies in the EU, including supermarket chains, must gradually report their products and activities' greenhouse gas emissions. That includes upstream - those of their suppliers - and downstream - their customers. Here, they commonly use the Greenhouse Gas Protocol. Supermarkets are responding to their shoppers' increasing environmental awareness. The largest supermarket chain in the Netherlands, Albert Heijn, has, for example, been displaying information about CO2eq emissions, or their estimate, on private label products and recipes since April last year. Those show what share of emissions the various chain processes - land use, production, processing, packaging, transportation, and the store - caused.
Transportation's share
Of food supply, which makes up 26% of the global greenhouse gas emissions, 53% is down to meat and fish production. That includes the production of fodder and the conversion of land use from, say, woodland to pasture. Producing plant-based foods (including land use conversion) causes only 29% of the total. Processing, transportation, packaging, and marketing account for four, six, five, and three percent of the food chain's total emissions. These are 2018 figures from the Joseph Poore & Thomas Nemecek study.
By truck
Transporting the Netherlands' food supply causes six percent of those emissions. Take fresh produce: most of that comes by truck, ship, or plane. Assume an average diesel consumption of 40 liters per 100 km for a refrigerated load of 20 tons when transporting tomatoes by truck from Almeria, Spain, to the Netherlands (2,200 km). Then, with CO2eq emissions of 3.468 per liter of fuel (source: Dutch standard list of CO2 emission factors), that trip causes 150g of CO2eq per kg of tomatoes in greenhouse gas emissions.
Tomatoes in a Dutch supermarket (the RIVM stats account for a mix of locally grown and overseas cultivation) come close to the 1kg mark. In that case, road transport makes up 15% of the total emissions. Compare that to the total emissions of a kilo of chicken, pork, or beef (4, 7, and 20 kg of CO2 eq. each), and the tomato's journey from Spain to the Netherlands' environmental impact is not bad at all.
By ship
Some imports come from overseas. Those include China (garlic and ginger, for example), South Africa (mainly citrus and grapes), and Latin America (tropical fruit). We use the "STREAM Goods Transport 2020" report by CE Delft to calculate maritime transport greenhouse gas emissions. On average, a container ship of 12,000-14,499 TEU (medium-heavy cargo) emits 7.8 g/t/km. That means shipping a ton of goods emits 7.8 grams of CO2eq. Based on that, the emission for transporting 1kg of goods from Peru to the port of Rotterdam (approximately 15,310 km) is 120g.
The Smart Freight Centre's "Clean Cargo 2023 Global Ocean Container Greenhouse Gas Emission Intensities" report comes to a similar conclusion: around 110g CO2eq. Clean Cargo is a partnership between sea container carriers, freight forwarders, and cargo owners. That calculation is based on a value of 71.7 g CO2/TEU-km dry cargo on the maritime route between South America and Europe. Avocados, however, are transported refrigerated. For reefers, Clean Cargo uses a value of 138.3 gCO2/TEU-km on that route. That brings the emissions to 0.21 CO2eq per kilo of avocados for the sea voyage from Peru, a quarter more than the car journey from Málaga, Spain, to the Netherlands.
But, road transport in Peru from the farm to the harbor and in Rotterdam to the product's eventual sales point must still be added. In the case of avocados and bananas, you should also consider the ripening process in Europe. Peruvian avocados will, thus, have an average carbon footprint of at least twice that of its Spanish counterpart. Nonetheless, that impact is negligible when compared to animal-derived foods.
By plane
Some products are flown into the Netherlands. Using the CE Delft database, we calculate that bringing in a kilo of mangoes in the belly of a passenger plane from Lima, Peru, to Schiphol (approximately 10,500 km) emits 6 kg of CO2eq. That is about 30 times more than by ship and 40 times more than by truck from Spain. Air freight mangoes have higher emissions than even chicken and almost as much as pork. Transportation by cargo plane is a little less harmful to the environment.
Air freight is generally used for highly perishable products from overseas countries of origin, like soft fruit, snow peas, and asparagus. That mode of transport's high emissions is why several supermarkets in the Netherlands have stopped selling fresh produce imported in this way. However, air transportation accounts for a tiny share of the total food kilometers (0.16%), compared to 10% by train, 31% by truck, and 59% by ship.
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Dutch greenhouse cultivation versus imports from Southern Europe
Then there is the question of whether growing and distributing, say, a tomato from a greenhouse in the Westland region of the Netherlands has fewer emissions than one imported from Almería. We may have found ourselves on shaky ground in the previous paragraphs regarding the various modes of transportation (sources are limited and depend on which elements you include in the analyses). That is even more true when it comes to comparing Dutch and Spanish greenhouse cultivation.
Here too, findings are based on only a few sources, which do not always rely on the same variables for their calculations. And even if we assume that research institutes work objectively, it can still rub you the wrong way when you read that a Spanish fruit and vegetable trade association commissioned a study, or that a breakdown was done for a shipping company partnership.
When comparing a kilogram of tomatoes from the Netherlands and Spain, it is important to know that the mix of tomato varieties in Dutch greenhouses differs from those in Spain. Also, the average yield of TOV and cherry tomatoes per square meter varies considerably. Plus, it is also not always clear whether studies include factors like the manufacture, lifespan, and elimination/recycling of greenhouse materials and equipment when working out CO2 emissions from cultivation.
That would, for instance, be plastic in Almería or glass and energy devices in the Netherlands. Whether or not the greenhouses use heating and/or lighting has a considerable impact on the results, too. For example, in 2022-2023, the average greenhouse gas emissions from tomato cultivation in the Netherlands, when growers all switched their lights off, differed from those in 2023-2024.
Let us assume a Dutch high-tech greenhouse produces an average of 70 kg of tomatoes per square meter per year. Then, the CO2eq emissions per kilo of tomatoes are 0.65. That is based on the Wageningen University & Research's (WUR) Energy Monitor for 2021. It says Dutch greenhouse horticulture has a 45.4 kg CO2eq/m2 annual emission. The Spanish trade organization Coexphal comes up with slightly different figures: In a comparative study, in collaboration with the University of Almería, they arrive at 0.92 CO2eq for cultivation in the Netherlands and 0.36 CO2eq in a greenhouse in Almería (add to that the 0.15 CO2eq for the truck journey to the Netherlands and you arrive at 0.51 CO2eq).
Despite the latter study being done on behalf of a Spanish sector association, you can expect the Dutch tomato supply chain to be less favorable - in terms of CO2 emissions per kilo of product - than the Spanish one. That is despite the transportation kilometers from Southern Europe and the five times higher productivity in a Dutch greenhouse. That could change, though, as the energy supply for lighting and heating becomes more sustainable. Also, there is still room for improvement in productivity in high-tech greenhouses. Spain could, though, also make further progress in productivity.
From January 1st, an individual CO2 tax applies to companies with a greenhouse area larger than 2,500 m2 to reduce greenhouse horticulture gas emissions in the Netherlands. That replaces the cost distribution system (CO2 sector system). The tax authority will collect that fee, calculated on the CO2 emissions caused by using natural gas. It will increase annually, from €9.50 per ton of CO2 emissions in 2025 to €17.70 from 2030.
Other environmental indicators
The CO2 footprint is, however, not the only aspect of the sustainability framework. Leo Marcelis, professor of Horticulture and Product Physiology at the WUR and leader of a sustainability study on high-tech greenhouses in 2021, states: "The study shows that Dutch high-tech greenhouses score highest on seven of the United Nations Sustainable Development Goals' 14 indicators relevant to horticulture, compared to other greenhouses used in Europe. This cultivation method uses very little water and land, and fertilizers have virtually zero emission. Also, 100% of high-tech growers use organic pest control as standard."
In conclusion, consider this comment: To reduce fruit and vegetables, or food in general's, CO2 footprint, we should strive for more sustainable cultivation, transportation, and storage methods, as well as ways to prevent food waste. Given that no less than 31% of all food produced worldwide is never consumed (Faostat 2019 figures), food waste alone is responsible for 6% of global greenhouse gas emissions. That is according to the Joseph Poore & Thomas Nemecek study. The CO2 that discarded food emitted during cultivation, storage, and distribution was, thus, for naught.
This article was previously published in Primeur May 2025. Click here for the link to the entire edition