Variability of Greenhouse Gas Footprints of Field Tomatoes Grown for Processing: Interyear and Intercountry Assessment

Abstract

Our study provides an integrated analysis of the variability of greenhouse gas (GHG) footprints of field-grown tomatoes for processing. The global farm-specific data set of 890 observations across 14 countries over a three-year period (2013–2015) was obtained from farms grown under Unilever’s sustainable agricultural code. It represents on average 3% of the annual global production of processing tomatoes: insights can be used to help inform corporate sourcing strategies and certification schemes. The median GHG footprint ranged from 18 in Chile to 61 kg CO2-equiv per tonne of tomatoes in India, lower than results reported in other studies. We found that footprints are more consistent within countries than between them. Using linear mixed effect models, we quantified the relative influence of environmental conditions and farm management factors. Key variables were area of production and the method of fertilizer application. GHG footprints decreased with increasing area of production to a threshold of 17.4 ha. Farms using single fertilizer application methods in general had a larger GHG footprint than those using a combination of methods. We conclude that farm management factors should be prioritized for future data collection, and more stringent guidance on acceptable practices is required if greater comparability of outcomes is needed either within a scheme, such as the Unilever’s sustainable agriculture code, or between schemes.

The importance of food systems and the environment for nutrition

“…For example, the livestock animal systems of Brazil have very different water and land use footprints than a pastoralist system in Northern Kenya ( 109–111 ). Tomatoes grown in hothouses have a different GHG profile than tomatoes grown in Southern California ( 112 ). Cashews have a much higher blue and green water footprint than peanuts ( 113 ).…”

Greenhouse gas footprints of palm oil production in Indonesia over space and time

“…Moreover, we calculated the Spearman's rank and partial correlation coefficients (Kim, 2015) between the district GHG footprints and the factors directly used in the GHG footprint calculations, including a) GHG emissions from above and belowground carbon stock changes, b) GHG emissions from new forest edges, c) GHG emissions from peat burning, d) GHG emissions from peat soil drainage, e) yields of FFB. The partial correlation coefficients were then used to quantify each of these factors' relative contribution to variability of district GHG footprints of CPO at the i) province, ii) island and iii) country level as per the procedure in Lam et al (2017). Factors that were assumed as constants based on literature values were not included in the analysis since they do not directly contribute to variability of GHG footprints.…”

A Novel Concept for Sustainable Food Production Utilizing Low Temperature Industrial Surplus Heat

“…Stoessel et al [76] arrived to similar conclusions when analyzing production in Swiss greenhouses. It should be noted that when looking at carbon footprint, the reported values are highly dependent on the methodology used, available information, and system boundaries [71,77]. With this in mind, the impact of the energy source can be observed when comparing the GHG emissions of Dutch tomatoes, which produce 1.7-2.8 kg CO 2 eq/kg when using natural gas and 1.1 kg CO 2 eq/kg when using combined heat and power (CHP) with increased energy efficiency [71,78].…”