Experiment to Break The WATER-ENERGY-FOOD Nexus

This is in a way continuation and almost repetition of the previous post where I have written about the "Sustenance Roof".

Last week I was invited to give a talk on my experiments with "Sustenance Roof" at the International Workshop cum Training on “Green Growth Strategies for Climate Resilience and DRR: Policies, Pathways, and Tools” Organized by the National Institute of Disaster Management (New Delhi) and the Institute for Social and Economic charge (Bangalore). The content of the talk is reproduced here with a few minor changes to suit the textual format. 

INTRODUCTION :

As Population increase, demands on finite water resources and energy services threaten to push the limits of what our environment can sustain. Another compelling reason to give cognizance to the water-energy nexus is climate change, which will result in significant alterations to precipitation patterns, with all that implies altered water availability and the power derived from water.

United Nations Water asserts in the World Water Development Report 2014,” Water, Energy, and food are inextricably linked…. The global community is well aware of food, energy, and water challenges, but has so far addressed them in isolation,”.
There are many synergies and trade-offs between water and energy use and food production. Here are some examples from the report;

1. Using water to irrigate crops can promote food production but it also reduces river flows and hydropower potential.
2. Diverting more water for irrigation compromises water for domestic and industrial needs.
   
3. Growing bioenergy crops under irrigated agriculture can increase overall water withdrawals and jeopardize food security.
   
4. Converting surface irrigation into high-efficiency pressurized irrigation may save water but may result in higher energy use.

Recognizing these synergies and balancing these trade-offs is central to jointly ensuring water, energy and food security.

The world Business Council for Sustainable Development (WBCSD) notes on its portal,” There is an intrinsic link between the challenge we face to ensure water security and other global issues, most notably climate change and the need to sustainably manage the world’s rapidly growing demand for energy and food.

Humanity needs to feed more people with less water, in the context of Climate Change and growing energy demand, while maintaining healthy ecosystems. ”
The FAO outlines the global challenge posed by the nexus

1. The situation is expected to be exacerbated in the near future as 60% more food will need to be produced in order to feed the world population in 2050.
2. Global energy consumption is projected to grow by up to 50% by 2035
3. Total global water withdrawals for irrigation is projected to increase by 20 to 25% by 2050 (Maybe much more, emphasis added).

NEED TO BREAK THIS NEXUS:  

Having acknowledged this nexus and almost linear inter-dependency, the need of the hour now is to cut this dependence as much as possible. We no longer can look at water or energy or nutrition in isolation. We need to innovate hybrid solutions that address this nexus and make each of them independent from the other to the extent possible. This hybrid model will be one of the ways to achieve sustainability in the long term.

EXPERIMENT WITH DECENTRALIZATION:

Keeping this nexus in mind and with the overall framework of sustainability, I have been experimenting with a decentralized model. This model, in my opinion, reduces the degree of this nexus to a large extent.

This experiment is limited to the basic needs of food, energy, and water. This is an ongoing experiment with many changes likely to take place depending on the results and observations made.

One of the ways of achieving this sustainability at a very local and decentralized level is to produce most of your essentials rather than buying them. This way you have more control over the quantity and quality of the inputs used and outputs produced and their respective environmental footprint.

Also, the energy and water footprint associated with logistics is reduced to a large extent.

I have been experimenting with the above over a course of time in my home.

I have been working on a model where my roof meets most of my water, food, and energy needs. In my opinion, this is as de-centralized as it can get. I call it the "Sustenance roof". Though I have not been entirely successful I have made some headway into this.

Below are my observations from the experiment so far.

WATER:

1. I have a roof area of about 105 SqM, considering Bangalore’s rainfall of 970 mm, I get about 970.00 x 0.85 (15% Loss) x 105.00 = 86,672 say 86,500 liters of water per year.

2. As a family of 3 plus a significant floating population and a decent rooftop garden (About 300 plants), our daily water consumption is about 430 liters.

3. With a rainfall of 86,500 liters, this translates to (86,500/430)= 201 say 200 days of water requirement or about 54%.

4.  More importantly, we put a portion of this water collected into the aquifer through a recharge well. Through this recharge well, the soil around the well got saturated in one year and now the well is yielding water which can, in turn, be used for irrigating the rooftop garden. Over the course of the next two years, with the water level in the Recharge well raising, it will be possible to meet the total water demand by the recharge well itself (Which was fed by the rainwater). 

1. 
   

   Recharge Well: 

   

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3. Impact on the Nexus (Water):

4. 1. The water which falls on the roof is directly used or recharged. Therefore the embodied energy is not converted to any form. 
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6. 2. There is no energy used in the treatment of this water. 
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8. 3. The water which fills the aquifer is withdrawn using solar power. 
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10. 4. Energy footprint of this water is "0". 
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12. 5. The water path, that is the distance the water has traveled from reception to consumption in this case is (7+3+3+7 = 20 M). This is perhaps the least distance the water can take before put into effective use. 
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14. 6. With the underground aquifer getting recharged over a course of time, we may not need any water from the grid. This will complete the cycle. Thus, we replenish the quantity of water and increase its quality too.
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16. 7. Since the water run-off outside the building is almost 0, this serves as a good way to reduce urban flooding (And its cost and energy involved in flood mitigation). 
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18. 8. When it comes to financial sustainability, Rainwater falling on one's roof or in one's aquifer is the cheapest source of water. Since there is no cost (and energy) involved in the treatment and supply of water, rainwater will be the cheapest source of water. The video below puts things in perspective. 
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21. ENERGY:

1. With a family of 3 plus a floating population, our daily requirement is about 5 units of energy (Electricity) including cooking.

2. We have the following to meet this demand

• A 3KW Rooftop solar PV system. It is also an Agri-voltaic system using the space below the solar panel for growing vegetables.

• A 150 Liter Rooftop solar water heater.
• A 2 Liter Solar Cooker. 

3. Our solar PV power system produces an average of 12 units per day that is more than double our requirement. So, we end up selling about 50% of the energy that we produce.

4. The Solar Cooker works well for good 220 to 250 days a year. Almost every day in summer we use our solar cooker for cooking our vegetables, rice, and dal. 

5. Since the cost of energy from the solar PV system is much lesser than LPG, we have switched to electrical cooking or induction plate for cooking (When we do not use solar cooker). So, our LPG is mostly for emergency purposes.

5. Since the solar thermal line is also connected to the kitchen, water used for cooking is preheated to a certain extent. This reduces the heating load of the induction stove or LPG

6. We plan to install a biogas unit to completely eliminate LPG.

7.  Heat seal white paint on the roof keeps the house cool. After adding few more plants on the roof directly above the bedroom, we have eliminated the need for AC in the bedrooms.

SOLAR ROOF.

PhotoVoltaic System

Solar Cooking 

 

HEAT SEAL PAINT FOR COOL ROOF. 

Impact on the Nexus (Energy):

1. 1. Rooftop solar is the least polluting source of energy currently.

2. 2. Research suggests that the EPBT or energy payback period for rooftop solar is about 1.4 years.

3. 3. Since the energy generator sits on the rooftop, no agricultural land or real estate was used for energy production. The tranmission of generated energy is not more than 5.0 M.

4. 4. The water footprint is recovered within 1.4 years or lesser.

5. 5. There is hardly any thermal losses in the rooftop thermal system.

6. 6. The T and D losses in rooftop PV system is nil or near negligible.

7. 7. The Rooftop solar system generates energy to lift the harvested rainwater from the recharge well or the sump thus reducing the embodied energy in water.

8. 8. Excess energy is pushed back into the utility grid which gets consumed in the neighborhood thus reducing losses in the grid as well as its related water, energy and carbon footprint.

9. 9. The Space below the solar panels is used for growing vegetables thus reducing the space footprint for food production.

10. 10. White roof keeps the roof cool as well as increases the rainwater run-off.

11. 11. White roof reduces the energy footprint for cooling the home during summers.

12. 12. White roof add albedo effect for the solar PV system

13. 13. White roof give the extra light for the plants on the roof by increasing albedo. (This is beneficial for the plants for photosynthesis process) .

14. 14. The energy generated here is almost independent of any water footprint since the electricity production process does not consume any water. 

1. FOOD:

2. We are far from self-sufficiency in so far as nutrition is concerned. We have tried growing ragi and rice on the roof without much success. However, the following experiments have been fruitful.

3. 1. The rooftop garden gives us enough leafy greens once in two days.

   2. About 10 to 12 days of vegetable requirements like brinjal, ladies finger, tomato, beans, etc are currently harvested from the garden.

   3. Papaya tree which is very easy to grow gives us an average of one large fruit every four days. Two papaya trees can theoretically feed a family.

   4. An added advantage of a rooftop garden is that you have full control over the inputs to the plants and are absolutely sure what you are harvesting.

   5. One is also consuming fresh and pesticide-free vegetables. This also eliminates the water and energy footprint of pesticides.

   7. The leaf composters and kitchen composters complete the nutrition cycle and the so-called waste get back into the garden.

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5.  ROOFTOP FARM.

   
   

   
   

   
   

   
   

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7. Impact on the Nexus (Food):

8. 1. The Photo-voltaic system is combined with the vegetable garden. This is called the “Agro-PV” system. 
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10. 2. No real-estate space is taken up for the vegetable garden. 
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12. 3. Most of the inputs for the garden (Manure) are produced from the kitchen and garden waste.
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14. 4. The harvested rainwater and the shallow aquifer water are used for irrigating the garden. 
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16. 5. There is no energy footprint embodied in the water that is used for irrigation. 
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18. 6. The vegetables and fruits grown on the roof have no logistics involved. Therefore, no carbon and energy/water footprint in the logistics. 
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20. 7. One  is also consuming fresh and pesticide-free vegetables. This also eliminates the water and energy footprint of pesticides.
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22. WASTE:

23. 1. All the kitchen waste goes to our kitchen composter.

24. 2. All the garden waste goes to our leaf composter.

25. Both the kitchen waste and garden waste is converted into beautiful rich compost which gets into our little garden. Thus the nutrient cycle is completed. 

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27. CONCLUSIONS:

    This is an everlasting experiment with many things to learn, unlearn, re-learn and change. However, there are few key conclusions;

28. 1. It is possible to decentralize for water, food and energy to the level of a roof for every household. 

29. 2. Most of the water, energy and food requirements can be met from one’s roof. 

30. 3. More the decentralization, lesser will be the degree of the nexus between Food-Water and Energy. 

31. All of the above are baby steps. We as individuals, as a society and as a nation have a long way to go. As mentioned earlier, sustainability is now more relevant than any other time in the history of mankind. COVID pandemic has given us an opportunity to relook at our paradigm of living and developing. It will be prudent to introspect and mend our ways before it is too late.

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33.  

Sustenance Roof...

Happy world environment day. 

Perhaps the "Environment" has more share in the days than anything else in the list of days we observe. For example, we have the 'World water day', 'world earth day', 'world biodiversity day, 'world ocean day', and so on. But the irony is, it is the "Environment" that is most misused and abused in spite of so many days in the calendar dedicated to observe and celebrate its magnificence, beauty, and grandeur.

We are today seeing the downside of globalization. Heavy dependence on foreign oil, goods, and services are hurting our economy. We are today realizing the perils of long-distance movement of food and other essentials. Materialistic living, heavy consumerism, unhealthy (and expensive) food habits are a result of infinite choices, which we have, fortunately, realized is not the best thing to have.

The word sustainability, in my opinion, has more relevance now than at any other time in the history of mankind. COVID Pandemic has shown us that we cannot take the environment and economy for granted. Call for #atmanirbhar Bharat could not have come at a better time. 

It is high time that we look at hybrid decentralized models of living (and perhaps development).

But the question now is what is sustainability. We hear this word hundreds of times every day. But what exactly does it mean to be sustainable? Is it measurable? Is there an index for our sustainability?. This is no doubt a difficult question. However, the following will give a kind of simple implementable definition.

"The paradigm of development where progress is achieved in all spheres of life and in all segments of the society where resources (Natural, Social, Biological and economic) are used in a manner in which its quality and quantity are not compromised for the future generations."

One of the ways of achieving this sustainability at a very local and decentralized level is to produce most of your essentials rather than buying it. This way you have more control over the quantity and quality of the inputs used and outputs produced and its respective environment footprint.

At a larger scheme of things, from the individual perspective, minimalistic living, consuming less and simple lifestyle contributes qualitatively to one's sustainability (and adds a lot of purpose and value to one's life).

I have been experimenting with both of the above for over a course of time in my home.

I have been working on a model where my roof meets most of my water and energy needs. In my opinion, this is as de-centralized as it can get. I call it the "Sustenance roof". Though I have not been entirely successful I have made some headway into this. I am writing a gist of my journey so far.

Water: 

1. I have a roof area of about 105 SqM, considering Bangalore’s rainfall of 970 mm, I get about 970.00 x 0.85 (15% Loss) x 105.00 = 86,672 say 86,500 liters of water per year.

2. As a family of 3 plus a significant floating population and a decent rooftop garden, our daily water consumption is about 430 liters.

3. With a rainfall of 86,500 liters, this translates to (86,500/430)= 201 say 200 days of water requirement or about 54%.

4. More importantly, we put a portion of this water collected into the aquifer through a recharge well. Through this recharge well, the soil around the well got saturated in one year and now the well is yielding water which can in turn be used for irrigating the rooftop garden. Over the course of the next two years, with the water level in the well raising, it will be possible to meet the total water demand by the recharge well itself .

Sustainability Check (Water): 

• About 50% of the water that we consume falls right on our heads. That means it is replenishable and this 50% of the water that we do not take from the grid can be supplied elsewhere thus adding to equitable distribution.
• Avoiding long-distance transmission of water saves the energy associated with it.
• With the underground aquifer getting recharged over a course of time, we may not need any water from the grid. This will complete the cycle. Thus we replenish the quantity of water and increase its quality too.
• Most importantly, the rainfall falling on our roof is the purest form of water. Thus we consume water in its purest form with the least possible conveyance. 

Energy : 

1. With a family of 3 plus a floating population, our daily requirement is about 5 units of energy including cooking.

2. We have the following to meet this demand

A. A 3KW rooftop solar PV system

B. A 150 Liter solar water heater.

3. Our solar PV power system produces an average of 12 units per day that is more than double our requirement. So we end up selling about 50% of the energy that we produce.

4. Since the cost of energy from the solar PV system is much lesser than LPG, we have switched to electrical cooking or induction plate for cooking. So our LPG is mostly for emergency purposes.

5. Since the solar thermal line is also connected to the kitchen, water used for cooking is preheated to a certain extent. This reduces the heating load of the induction stove or LPG

6. We plan to install a biogas unit to completely eliminate LPG.

7. Heat seal white paint on the roof keeps the house cool and reduces the air conditioning requirement to a maximum of 20 days in a year.

8. Of course, no electricity is used for hot water required for bathing since the solar water heater takes care of the hot water required for bathing.

Sustainability Check (Energy): 

• All our energy requirements are met by renewable energy.
• The transmission of this energy is not more than 5 meters.
• We also just consume less.
• Arithmetically we produce more energy than we consume.
• Not only we consume energy from renewable sources, but we also push excess renewable energy that we produce back into the grid (@ less than market prices).
• Both in terms of quality and quantity, this model seems to pass the sustainability check.

Waste : 

1. All the kitchen waste goes to our kitchen composter.

2. All the garden waste goes to our leaf composter.

Both the kitchen waste and garden waste is converted into beautiful rich compost which gets into our little garden.

Sustainability Check (Waste):

• No wet waste leaves the house. All the nutrients are recovered and reused.
• Plant nutrition is locally produced without spending energy on production and transportation.
• Plastic and non-bio-degradable waste however are given out for recycling. (we are not sure how much is actually recycled).

Food: 

We are far from self-sufficiency in so far as nutrition is concerned. I tried growing ragi and rice on the roof without much success. However, the following experiments have been fruitful.

1. The rooftop garden gives us enough leafy greens once in two days.

2. About 10 to 12 days of vegetable requirement like brinjal, ladies finger, tomato, etc are currently harvested from the garden.

3. Papaya tree which is very easy to grow gives us an average one large fruit every four days. Two papaya trees can theoretically feed a family.

4. An added advantage of a rooftop garden is that you have full control over the inputs to the plants and absolutely sure what you are harvesting.

5. One is also consuming fresh and pesticide-free vegetables.

6. Most importantly growing your food is fun and a spiritual exercise.

7. The leaf composters and kitchen composters complete the nutrition cycle and the so-called waste gets back into the garden.

Sustainability Check (Food):

1. About 50% of our vegetable requirement is met right on the roof.

2. Not only the food, the water required for growing the same also falls on the same roof.

3. The manure and the nutrient input for the plants are from the kitchen in which the same vegetables are cooked.

4. It is a long way for food sustainability. However, it is a start.

Cycling: 

Using a bicycle for running local errands can save expensive imported oil and at the same time reduce noise and air pollution. it is good exercise too.

Bangalore roads are really not bike-friendly. However, I am trying to use the bicycle at least for local commutes.

Bio-diversity: 

Thanks to some of the above initiatives and the presence of many trees around, we are able to attract some common birds in the neighborhood.

Observing the bio-diversity is a wonderful way to stay grounded and connect yourself to the larger scheme of things (and perhaps discover if at all there is a larger scheme of things).

Apart from the above initiatives, we are practicing the below quite regularly ;

1. Plant at least 2 trees a month in any open space anywhere.

2. We are trying to consume as little as possible. For example, we have stopped buying fancy electronics, fine dining is almost stopped, we are reducing car travel, all the members in the family use cycle, buying stuff from the local store, etc

All of the above are baby steps. We as individuals, as a society and as a nation have a long way to go. As mentioned earlier sustainability is now more relevant than any other time in the history of mankind. COVID pandemic has given us an opportunity to relook at our paradigm of living and developing. It will be prudent to introspect and mend our ways before it is too late.

Paradigm in water conservation.

I have been working in the area of Rainwater harvesting for the last 15 years. Though most of my work involves augmenting water supply, I have been also involved in water conservation and demand side management projects as well.

Since I am involved in decentralized projects in housing colonies, factories etc, the design consideration is generally “LPCD” or “Liters per capita per day”. Most projects in housing complexes are designed with the demand pegged at 135 LPCD (though in most urban cases usage is little higher)

Now, if one looks at the number ‘135’, it is the water required per person per day. This is also a legal right of every citizen in India. The breakup of this 135 is given below;

  

USE	LITERS/PERSON/DAY
Drinking	3.00
Cooking	4.00
Bathing	20.00
Flushing	40.00
Washing-clothes	25.00
Washing Utensils	20.00
Gardening	23.00
Total	135.00

The table above is the water requirement per person per day for a hygienic decent living. It is not in the scope of this article whether this is achieved in India or if these numbers are justified.

For the purpose of analysis let us assume that this number is justified.

However, this 135 LPCD is not the amount of water consumed by a person every day. This is just the “direct” demand or consumption by a person. In other words, this is the water that a person consumes from his or her tap directly every day.

The “water footprint” of an individual is much higher that 135 LPCD. We all consume a lot of water indirectly. Our net water footprint is the sum of our direct consumption and indirect consumption.

The food we eat, our clothing, transportation, electricity, consumables, paper, travel, fuel etc have substantial water footprint. This water footprint is rather very difficult to measure or quantify.

In this article I have tried to determine broadly what is the net water endowment available per capita in India. This is an attempt to indirectly determine our water footprint. The below calculations are however broad and general with many assumptions.

The other motivation for this article is to drive home a point on equitable and sustainable water use and distribution.

At a slightly larger picture, we have the following numbers /Data available for India

•  India’s annual Rainfall + Snowfall run off  = 1600 Billion cubic meters
• Assuming 50% reaches the seas, we have the net run off of 800 billion cubic meters. That is 800,000 billion liters.
•  In other words, the annual water endowment to India is 800,000,000,000,000 Liters
• Population of India is 130,000,00,00.00
•  Annual water endowment per person = 800,000,000,000,000/130,0000000 = 6,15,384.00 Liters
• Say 6,15,000 liters is the annual endowment of water per person in India
• This translates to 6,15,000/365 = 1,684.00 liters per person per day. (Think about it, density of water is 1000 kg/m3. Each individual consuming 1600 liters of water a day is equivalent to energy of 1600 Kgs. That is 1.6 Tons equivalent. So, an individual of 80 Kgs consumes an energy equivalent of 1.6 Tons that is 20 times his weight every day. A tiger weighing 350 kgs consumes a deer of 40 kgs for 3 days. There is no indirect consumption in the animal kingdom)
• With 135 LPCD being the direct component, the indirect component of the water footprint is 1,684-135 = 1,549 LPCD say 1,500 LPCD.
• In summary, our water footprint looks like
•     Ø  Direct component (Domestic consumption): 135 LPCD or 8%
•     Ø  Indirect component: 1549 LPCD or 92%
•  As discussed, this 1500 liters is a combination of water used for food, fuel, consumables, paper etc.

NOTE: I have not addressed the question of equity here. We are only discussing the net endowment.

The reason I did this calculation is to drive home the point that we have to look at the larger picture about water conservation than merely looking at taking bath in half a bucket of water or switching off the tap while brushing though these are very much required.

All steps taken at the domestic level to conserve water only reduces the direct demand. Say with best efforts, we may be able to bring our domestic demand from 135 to 100 LPCD. In the larger scheme of things, it translates to about 2% which is also quite significant.

However, we have to look beyond domestic demand and supply calculations for an effective paradigm in sustainable and equitable water distribution.  

Addressing the indirect component of water footprint, we can significantly reduce water consumption and also augment the direct component if required (for health and hygiene reasons).

Hence the point I am trying to make here are;

• Mere reduction in consumption of goods and services can bring down water footprint significantly.
• Larger impetus must be given on sustainable agriculture (For example No sugarcane in arid and semi-arid regions).
• Import substitution of certain goods can save plenty of water. (Water footprint in logistics)
• Skipping a meal once a week is a good way to conserve water.
• Going vegan twice a month and fasting twice a month is significant water savings.
•  Reduce meat consumption or if possible, stop.
• Locally grown food consumes far lesser water. (With my experiments in rooftop garden, we are able to pluck out vegetables for a family of 3 every alternate day at a water footprint of 50 liters a day that is 16 LPCD.
•  Rooftop solar is a good way to reduce water footprint. Thermal power plants are water guzzlers.
• One flight less per year is perhaps equivalent to reducing domestic water footprint from 135.0 to 125.0 per day if not more.
•  Reducing leather is another great way to reduce water footprint.

The list can go on. But the point is we have to give more impetus on reducing consumption and switch to sustainable consumption.

Education and practicing water conservation measures at home or office is good and is required but we must also look broader and deeper into water footprint and also focus on structural and fundamental changes to become more sustainable, equitable and self-sufficient is water resource.

Sustainability and Equity:

Now an important question arises on why we must reduce direct or indirect consumption. India’s endowment in terms of rainfall is more or less fixed and it is more or less consistent at 1600 billion cubic meters per year. It is a replenishable resource and does come every year, like it or no.

My remarks on this are below;

1.   Though our endowment is by and large consistent , our population is growing. We will need to feed more mouths with less water. Rainfall was 1600 Billion cum in 1930 when population of india (Undivided India) was 40 crore. In 2020 we have about 135 crore people in India with the same available water.
2. Here comes the question of equity. Unfortunately, in India this legal right of 135 LPCD is neither achieved nor measured. Even in urban areas we do not have supply of 135 LPCD.

3.  With increasing temperatures there is a need to enhance the direct demand from 135 to may be 200 LPCD.

4.   Though there is no real data on consumption in India, one can be very certain that there is a huge disparity in consumption. In urban places, I am sure our water footprint is about 4000 LPCD. To reduce this gap and to be more equitable, reduction in consumption is inevitable.

5. Most importantly, though there is a water endowment , it is not available when we need it . It becomes imperative to conserve the precious resource for the time of need.

The term The term 'Conspicuous consumption' was first coined by American economist Thorstein Veblen in the late 19^th century. The term has changed its meaning over the last 120 years to very ugly levels.

Given what the world is going through, it is high time that “Sustainable consumption” makes its way into economies and economic theories for a better and cleaner world.  


Next time you visit the amazon website remember the time has come to shift from from 'Conspicuous consumption' to 'conscious consumption',