The figure above illustrates the relative differences in emissions of CO2 and CO2 equivalents between importing bananas from Ecuador and producing them locally in Paphos. The two biggest contributors to emissions are from water irrigation (which is far higher in Paphos), and from transport to Cyprus (which is far higher from Ecuador).
Methodology
Bananas Locally Produced in Cyprus
Paphos banana emissions include those from transportation, packaging, chemical treatments, and water irrigation. The user must input the mass of bananas they are considering purchasing, and all other numbers are found from online sources.
To calculate transportation emissions, the calculator uses a refrigerated truck emissions factor, assumes a distance from the Paphos plantations to an average grocery store in Cyprus, and multiples these values as well as the mass of bananas purchased to find the total emissions.
Packaging and chemical treatment emissions were calculated using guidance from an MIT banana emissions case study. While the process is clearly outlined in the MIT report (cited below), here is a summary: we used the average weight of a cardboard banana box as well as its capacity, then considered the emissions associated with the production and disposal of the box. Using these numbers, we can find the total emissions from the cardboard box and divide this by the kg of bananas being purchased. As far as chemical treatments, the MIT report gives an average value of 23 g of CO2 per banana, which is then multiplied by 7 bananas per kg (an assumption) and the mass of bananas to be purchased to find the total chemical emissions.
To find the emissions from water irrigation, we found Paphos specific data on the size of banana plantations, the amount of irrigated water used, and the amount of bananas produced. With these values, it is possible to calculate the amount of water needed per kg of bananas. Because we could not find emissions factors for irrigation in Cyprus, we used an emissions factor for irrigation in California because California is constantly in draughts and has similarities with Cyprus regarding obtaining usable water. The emissions factor for California irrigated water is multiplied with the volume of water needed per kg of Paphos bananas and mass of bananas to be purchased by the user, giving the total emissions from water. This number can then be added to the emissions from transportation, packaging, and chemical treatments to find the total emissions of producing the desired mass of bananas. It is important to note that this final value is in CO2 equivalents, meaning other greenhouse gas emissions are also included in this final value.
It is difficult to compare our emissions per kg of bananas produced in Paphos with other sources as very little data is published online for places with climates similar to that in Cyprus. When compared with the value for bananas produced in Latin America (as found in the MIT case study), the value is lower by about 5%. This suggests that our data is likely reasonable, and the differences between transportation costs and water emissions somewhat balance out.
Sources:
Refrigerated truck emissions factor
https://consumerecology.com/carbon-footprint-from-the-regional-distribution-center-to-retail/
Under section describing emissions from distribution centre to retail. Refrigerated truck, 7.5-15 tonnes.
MIT bananas case study: cardboard banana box production and disposal, chemical treatment emissions, comparison with other sources
Cardboard box: page 6-7 under “Packaging” heading. Chemicals: page 7 under “Chemicals” heading. Value used to compare with our emissions per kg bananas in Latin America: page 7 under “Results” heading.
Paphos irrigated area banana farming information
Table 11: Irrigated area of Paphos banana farms
Table 12: Paphos banana water needs
Bananas produced per year in Paphos
Page provides bananas produced in Paphos in 2020 in tonnes of bananas. This is converted to kg of bananas by multiplying by 1000.
California irrigated water emissions factor
Section 3: Energy consumption and CO2 emissions in reuse systems. Two paragraphs above section 4 heading, can find emissions factors for water irrigation in California.
Bananas Imported from Ecuador
Similar to the Paphos banana calculations, the Ecuador banana emissions include those from transportation, packaging, chemical treatments, and water irrigation. The user only needs to enter the quantity of bananas they are purchasing and the calculator already knows the rest.
Beginning with transportation, the calculator uses estimates for the shipping and truck distances to be travelled and multiplies these with an emissions factor and the mass of bananas we are considering. The transportation required includes a truck driving the bananas from plantation to shipping port, a cargo ship transporting the bananas from Ecuador to Cyprus, and then a truck driving the bananas from Larnaca to a grocery store. As a note – we assume that the trucks are refrigerated.
Next, we consider packaging. This process is the same as in the Paphos banana section, in which the MIT banana emissions case study is used. In summary, we find the average mass of a banana box as well as how many kg of bananas fit into each box, and divide the total emissions of cardboard production and disposal by the mass of bananas per box. This value is then multiplied by the mass of bananas to be purchased to find the total packaging emissions for the desired amount of bananas.
For chemical treatment emissions, we used a value for average emissions of chemical treatments per banana (23 g / banana) and converted this to kg CO2e per kg bananas. This number is then multiplied by the desired amount of bananas to find the total chemical treatment emissions.
Finally, we considered water irrigation. For the amount of water needed per mass of bananas, we used data from a study specific to small banana farmers in Ecuador. It is important to note that we removed the amount of water that is obtained through rainfall such that we are only considering irrigated water. We then used an emissions factor for water irrigation in Toronto, Canada, which also experiences a lot of rainfall per year, and multiplied this with the amount of irrigated water needed per mass of bananas to find the total irrigation emissions.
By summing up all the emissions from each sector considered, we find the total emissions of bananas grown in and imported from Ecuador. Additionally, the value reported is in CO2 equivalents meaning greenhouse gases other than CO2 are also reported.
Our final emissions per kg of bananas imported from Ecuador is compared with the final value in the case study published by MIT. The values of 0.734 kg CO2e/kg bananas and 0.847 kg CO2e/kg bananas as found by us and MIT respectively are off by only 13%. This suggests that our data is accurate, however it also shows that there are important differences in our calculations such as us not including the electricity required to power lights and other technology within the banana plantations and slight differences in transportation distances.
Sources:
Refrigerated truck emissions factor
https://consumerecology.com/carbon-footprint-from-the-regional-distribution-center-to-retail/
Under section describing emissions from distribution centre to retail. Refrigerated truck, 7.5-15 tonnes.
Shipping emissions factor
Clean cargo aggregate average trade line emissions factors 2015-2019 table. 2019 South America to/from Africa reefer value used.
MIT bananas case study: cardboard banana box production and disposal, chemical treatment emissions, comparison with other sources
Cardboard box: page 6-7 under “Packaging” heading. Chemicals: page 7 under “Chemicals” heading. Value used to compare with our emissions per kg bananas in Latin America: page 7 under “Results” heading.
Toronto irrigated water emissions factor
Section 3: Energy consumption and CO2 emissions in reuse systems. Two paragraphs above section 4 heading, can find emissions factors for water irrigation in Toronto.