Water footprint of food and cooking fuel

Rice and wheat have large water footprints in rural India

Madhya Pradesh has the largest blue water footprint for food (334 m3/cap/year) and the blue water footprint from wheat contributes 87%. (Image: Pixabay)

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26 Mar 2021, 9:03 am

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Water is a basic resource for food and fuelwood production. In general, people in rural areas of India consume carbohydrate-rich staples with small amounts of animal foods. They mostly depend upon fuelwood for cooking.

This paper The water footprint of food and cooking fuel: A case study of self-sufficient rural India is based on a study that assesses the water footprints for food and fuel consumption in rural India. Published in Journal of Cleaner Production, Volume 281, 25 January 2021 the paper has been authored by K Das, PW Gerbens-Leenes and S Nonhebel.

The research question is: What is the green, blue and grey water footprint (WF) of food and cooking fuel consumption per province in rural India (m3/cap/year). It used the water footprint method for the quantification.

Water footprint: the concept

To visualize the relationship between consumption of goods and freshwater use, Hoekstra (2003) introduced the water footprint (WF) concept which measures the freshwater appropriated to produce goods or services, expressed as a water volume per unit of product.

The WF includes three components: green, blue and grey WFs. The green WF is the volume of rainwater consumed during production. The blue WF is an indicator of the consumptive use of fresh surface or groundwater. The grey WF is an indicator of the degree of freshwater pollution and is defined as the amount of freshwater needed to dilute polluted water to accepted water quality standards (Hoekstra et al., 2011) (Schyns et al., 2019).

Food dominates water footprint globally

Globally, the consumption of food dominate the global average annual per capita WF, with cereals contributing 27%, meat 22% and milk 7% (Mekonnen and Hoekstra, 2011a), but differences among countries are large, especially between developed and developing countries.

In general, people in developed countries have a large contribution of animal foods to their total food consumption, however, developing countries have food consumption patterns based on carbohydrate rich staple foods with little animal foods (Grigg, 1995) (Winnie Gerbens-Leenes and Mariotti, 2017) (O and “Staple foods: What, 2019).

A large fraction of population in developing countries uses inefficient cooking fuel and cookstoves, where fuelwood mostly used for cooking their food and traditional cookstove (Maccarty and Bryden, 2016).

Study findings

This study aims to give an insight into the water volumes needed to provide both food and cooking fuel in rural India. It answers the following research question: What is the blue, green and grey WF for food and cooking fuel consumption of the rural population per province in India?

Data on food and fuelwood consumption were derived from the National Sample Survey (2011–12). Foods were categorized into 6 groups: 1. Rice; 2. Wheat; 3. Oils and fats; 4. Milk; 5. Other animal foods; and 6. Others. Cooking fuel includes: 1. Fuelwood; 2. Kerosene and 3. LPG. Data related to water footprints of food were derived from literature reviews and in case of fuelwood, the water footprints were calculated for all the provinces of India.

Finally, the total water footprint of per capita consumption is calculated by adding the water footprint of food and fuelwood. The result shows that there is a large variation in the green, blue and grey water footprints for food consumption across the provinces of India. The average water footprint for food consumption is about 800 m3/cap/year and for fuelwood is 1630 m3/cap/year.

Rice and wheat dominate the green, blue and grey water footprints for food, with variations among the provinces. The green water footprint of rice is larger than the green water footprint of wheat, while wheat has a larger blue water footprint.

For cooking fuel, the average water footprint of fuelwood is much larger than the water footprint of fossil based cooking fuels. The total water footprint for fuelwood is twice the water footprint for food, showing that in rural areas of developing countries, fuelwood is water intensive with large impact on freshwater resources.

Future prospects of increasing consumption of animal products will increase water footprints. However, if cooking fuel is also considered, switching to fossil cooking fuel lowers water footprints far more and compensates the increase due to larger animal food consumption. The trends for cooking fuel found in India might also be relevant for other developing countries.

Green and blue water footprint of fuelwood per unit of energy in rural India.

Total water footprint for food and cooking fuel across all the regions of India.

Conclusion

This study showed the importance of including the water footprints of cooking fuel in water footprint analysis. In self-sufficient rural India, the total water footprint for cooking, mainly due to the use of fuelwood is twice the water footprint for food, showing that in the rural areas of India, a developing country, especially fuelwood is water-intensive with a large impact on freshwater resources. In rural India, the average water footprint for food is 800 m3/cap/year and for fuelwood m3/cap/year. Green water accounts for 57%, blue water for 30% and greywater for 3% of the total water footprint of food. Rice and wheat are the main staple foods with large water footprints and large contribution to the total water footprints of food consumption.

Rice, wheat, oils and fats contribute most to the total water footprint of food in rural India. In the north-eastern provinces, rice and wheat water footprints together contribute 70% to the total WF. 10–20% of the water footprint related to wheat consumption. In Madhya Pradesh and Puducherry, in the central and southern part of India, the wheat water footprint contribution is larger than the rice water footprint contribution. This is due to the combination of large wheat water footprint and large wheat consumption.

The blue water footprint ranges from 6 m3/cap/year in the north-east to 334 m3/cap/year in the central and west region. Bluewater footprints for food are the largest in central India, and in some provinces in the south region. Variations are large among the provinces. Madhya Pradesh has the largest blue water footprint for food (334 m3/cap/year) and the blue water footprint from wheat contributes 87%. The smallest blue water footprint is in Mizoram (6 m3/cap/year). The relatively small blue water footprint in the east and north-east is due to large rainfed rice consumption. Large blue water footprints in the southern provinces are caused by irrigated rice consumption.

For cooking fuel, the average water footprint of fuelwood is much larger than the water footprint of fossil fuels. There is a large variation among the water footprints for food and fuel across the provinces. The green water footprint for fuelwood consumption is largest in the south and north-east provinces (2800–3500 m3/cap/year. However, there is also a relatively large green water footprint in the central and east regions. The blue water footprint is relatively large in the western regions.

For food consumption, in all Indian regions, water footprints are dominated by green water footprints and despite the differences in consumption, variation of total water footprints for food consumption is small. In rural India, the blue water footprint of food consumption is relatively small compared to the blue water footprint for fuelwood consumption.

For rural India, future prospects of increasing consumption of animal foods will increase the water footprint. However, if also cooking fuel is considered, switching to fossil-based cooking fuel will lower water footprints far more and can compensate an eventual increase of larger consumption of animal foods. The trends found for India might also be relevant for other developing countries.

Groundwater