Tuesday, October 2, 2007

Diets, Consumption and Global Warming

Part 6 of the six part series on Pune pollution and environment.

Sometime back a blogger left a comment on one of my earlier blogs, suggesting a number of ways to reduce pollution. Among the many was, "don't drive, walk as much as possible", the rationale obviously being that using less fuel is good for the environment. In these times, when global warming is one of the big talking points, walking is the healthy and responsible way forward. But is it?

A few weeks ago I read a strange article in the Times of London, where a calculation was presented. Apparently if a person walks to the store and around the neighbourhood for errands, let's say around 3 miles or 4.8 km, then providing that person with enough calories to replace those burnt, emits more CO2 than if the person had driven to the store. Driving to the store and back according to the calculation will emit around 0.9 kg of CO2. On the other hand, walking to the store will burn around 180 calories. To replace that with a mostly beef diet will result in 3.6 kg of CO2 emissions. With a straight face the report says “The troubling fact is that taking a lot of exercise and then eating a bit more food is not good for the global atmosphere. Eating less and driving to save energy would be better.” This says a lot about how energy intensive the meat food production chain has become in developed countries. But not just the meat. If you try to replace those 180 burnt calories with milk, it will result in 1.2 kg of CO2 emissions, still more than driving. In 2002, in the United States, the food production system accounted for around 17% of fossil fuel use. Going vegetarian or "vegan"will reduce this burden. Another study has calculated that the difference in greenhouse gas emissions due to shifting to a veggie diet is as much as that achieved by shifting from an SUV to a standard car, a reduction of about 1.4 tons CO2 per person per year. Cutting meat altogether from our diet seems very unpopular at present. Recently, Michael O'Leary, the boss of budget airline Ryanair, came under heavy criticism when he remarked that global warming can be eliminated by slaughtering the world's livestock. Off course going veggie alone doesn't help as illustrated by this cartoon.

I walk a lot in Pune, so do I actually contribute more to global warming by walking and not driving. Suppose following the U.K example I walk around 4.8 km per day and burn about 200 calories. My diet these days is almost entirely vegetarian. Based on a Ford Foundation study on energy intensity of Indian agriculture I calculated that producing 1 kg of food will result in about 2 kg of CO2 emissions. This includes energy required for the entire food production chain including fertilizers and transportation. If I burn 200 calories, eating healthy I would have to eat about 300 grams of various vegetables to make up those burnt calories resulting in about 0.6 kg of CO2 emissions. Much less than the person walking in U.K. and gorging on beef later. Energy intensity of Indian agriculture is still much less than the industrialized food production of the west. If I drive those 4.8 km in my Fiat (that old beast still chugs along) this will result in about 1.15 Kg of CO2 being emitted. But if a person zips around on a two wheeler, driving 4.8 km to the store and back will emit around 0.19 kg of CO2. In Pune, walking over short distances is better than driving a car, but not better than driving a two wheeler when it comes to replacing burnt calories and emitting greenhouse gases.

This will work as long the person maintains a particular weight. If a person starts overeating then all those extra calories represents extra emissions of CO2. This is likely to be a problem in urban India with all the new found prosperity. Trends of weight increase in urban Indians suggest that 40 to 50 million Indians have become overweight over the last few years and it could get worse. To gain one pound a week one has to eat 500 calories extra per day. That is a total of 3500 extra calories. Urban Indians are becoming fat not by eating huge amount of healthy veggies, but by stuffing themselves with calorie rich foods like sweets and oil rich fried stuff. That would mean they will require about 900 - 1000 grams of extra food to put on 1 pound of weight or 20 kg of extra food to gain 10 kg weight. The energy intensity of producing smaller amount of sweets and oil is probably the same as consuming larger amount of veggies. Going by this assumption, that would mean additional emissions of about 230 kg CO2 for every 10 kg of weight increase. If 50 million Indians become overweight by 10 kg that will result in additional emissions of 11.5 million tons of CO2. The figure will be much more if they start eating more chicken, since poultry industry is becoming very energy intensive, western style. My calculations are probably off by some amounts but the intent is to show that obesity and consumption has unexpected consequences.

How are urban Indians doing when it comes to personal lifestyles and the contribution thereof to global warming? Why not find out? Use the personal CO2 calculators I have listen below to calculate how much you contribute to global warming.

Carbon Counter
Conservation Fund Calculator
Carbon Footprint Calculator

To help you out here is a conversion list:

1 Dollar ~ Rs 40
1 gallon = 3.37 litres
1 kg = 2.2 lbs
One unit on your MSEB electricity bill ~ 1 kwhr.
1 cylinder of cooking gas (Propane) ~ 16.5 litres
Fuel Economy: 1km/lit = 2.35 miles/gallon
1000 kg = 1 ton

Compare your emissions with those of households of other nations given below.
CO2 Household Emissions by Country:
Australia - 14 tons/yr
China - 2.4 tons/yr
U.K- 9.8 tons/yr
U.S.- 19.06 tons/yr.

In the interest of full disclosure, I emit about 4 tons per year, a little more I suspect than many Puneites, primarily due to international travel.

This has been a fun series to write. I will be writing on and off about Pune so watch this space.

Part1. Idling and Pollution
Part2. PMT buses and Pollution
Part3. Rickshaws and Pollution
Part 4. Urban Forests and Clean Air
Part 5. Sensing Corruption Remotely


  1. Which points to start on...
    Probably the original data - although the Times is reputable even the best get it wrong!
    All meat is not the same - sheep, goats, chickens farmed on land unsuitable for growing crops skews the figures somewhat.
    Let's start by trying to improve the world by improving ourselves - the argument being if we are to create a healthy world we must start by making ourselves healthy so; be vegetarian, walk not drive and be especially careful to enjoy the wonders of ecological mathematics!

  2. The easiest way to save energy is to switch to super efficient LED bulbs, check out http://led.section9tech.com

  3. Suvrat,
    I forgot to point out that 1 G = 3.784 L.

    I start in reverse gear. My last point was not about the assumptions or approximations you have made, but was about those whose reports you have relied upon. As I understand you are relying on finished data received from various sources, who may have carried out the primary data collection and subsequent analysis. I do not know if they give out in their publications set of assumptions or approximations made and the methodology followed while pursuing their line of research. It is here that the BIAS in research invidiously enters depending upon the world view of the researchers or the funders.

    In a very general sense, Vandana Shiva says that Indian agriculture, at least majority of it, is practically carbon neutral due to low intensity use of farm chemicals and mechanised power reliant on fossil fuels.

    I am in no position to contest the figures you have sighted at point 3. But some how I find the figure of 13% for industrial sectors contribution to GHG low. Take for example conversion of bauxite to alumina, a highly energy intensive process using electricity and therefore profitably carried out where that power is cheap. The cheapest source of power is Hydro and that is how Canada is the leading and most competitive producer of aluminium. Most think Hydro-power is best from climate change perspective. I am told think again ( see this article : "Hydropower : Not Clean energy"). Dams release methane. Angad's text book says CH4 is 4 times as deadly as CO2 for GH effect, the Times article you sighted pegs it at 20, and this article raises the bar to 24 times. Now, who should we believe? Another example touted as a great reducer of fossil fuels is ethanol blending. Many have argued against it from the point of view of the food security of the poor. But there is one more flip side to it. Production of ethanol involves release of CO2 ( C6H12O6 (zymase) = 2 CH3CH2OH + 2 CO2 ). Is this factored in while taking a position?

    When Earth's atmosphere was in the making, at some point the O2 levels were too high for life to exists. O2 is a highly reactive element that we always treat as benign. Reduction in O2 levels made life possible. Growth of life, especially non-microbial, means more use of O2 and therefore its depletion and consequently the rise of CO2. The process has been on for a very long time. But this secular trend was imperceptible, until may be 50 years ago, when the first stirrings of climate change occurred. Much work has been done since then, and far more is required to be done in years ahead. The workings of the climate is one of the most bedevilling issues of all times. Almost all, when they take a position based on their respective world-views, are approximating only a part, a small part of that reality, as they see it. These thousands of flowers of creative analysis should bloom before a synthesis is reached. I am simply appreciating their varied, and often conflicting, splendour.

    I have downloaded a film from the net called "The Great Climate Change swindle" that came as a reply to the report of UN-IGPCC. It has interviews of many scientists, who hold that the present climate change witnessed is :
    a short term deviation in a very long term pattern and such changes have happened even in the past.
    earth's climate is under far greater influence from factors without than from those within.
    While I do appreciate the partial truths in all these positions, I have no knowledge to take a informed position one way or the other, and probably there is no need. Each one tempers the extremes in the other bringing in a semblance of balance to our search for truth. I seek only to juxtapose conflicting partial truths to see how they fare.

    Cheers / Sadanand.

    PS : I believe a complete overhaul of the energy intensive and avaricious lifestyles of the western mode of living is the most critical change that is crucial to the success of Mission-Climate. Otherwise the billions in China and India and elsewhere, aspiring to follow American dream (pursuit of happiness) will doom everything. A leap in and of technology is the only imponderable here.

    Hi Sadanand-

    You raise some excellent doubts. I will answer as best I can-

    1) the comparison was only for CO2 or technically CO2 eq. as it is the main warming gas, not other pollutants. the effect of SOx and particulate matter on global warming is controversial, so it is hard to include that. but if you are talking of SOx and particulate matter as just more pollutants that cars spew out, then yes, there are additional pollutants that vehicles emit. But then, food production come with other pollutants as well. Fertilizers and pesticides get into groundwater and into our food chain and so on. So everything has a cost.

    2) I have seen people gain weight by exercising and people losing weight exercising. It works both ways, depending on the starting point and what the person is trying to achieve. As far as the Indian middle class is concerned, there is no question that the vast majority of them are gaining weight.

    3) Excellent point. The calculations as I presented them are distorted. I did come up with some figures though. In this figure, break up of the greenhouse gas emissions by activity is given. Industrial production in totality comes to around 13%, out of which iron, steel, machinery are an even smaller percentage. In contrast agriculture as an activity alone (not counting industrial processing and transportation and refrigeration of food) accounts for 13.5% of emissions of greenhouse gases. Also revealing is land use changes (deforestation) making up 18% of emissions. the vast majority of cleared forests are for planting soy bean and sugarcane in the Amazon and in lowland Indonesia. This has to be included in the total cost of food production. The second figure (see attached) is for U.S emissions but confirms the overall world wide trend. Emissions from all industrial processes in around 105 million tons CO2 eq. In contrast agriculture emissions (again just agriculture alone without the industrial processing component) account for 426 million tons CO2 eq, as the table puts it politely "enteric fermentation' alone produces more greenhouse gases than industrial processes.

    4) Sure, I used a lot of assumptions, but these figures do suggest that I am on the right track. As you said the other big motivation was to provoke and shock people.


  4. an average american or english person is overweight .. so burning 200 calories is in fact quite favorably leans towards reducing carbon emissions as compared to driving .. thats in the name of exercise though ..

    i would dismiss your blog entry as nothing more than a humorous read .. and thats not my ignorance if you would think so .. just my opinion ..

  5. Really Funny Story, but to think upon it rationally , why this Green House Effect wasn't there in earlier times, because We have disturbed the whole food cycle & disturbed the environment & our live to that extent, Its been good to have vegan diet, on the cost of CO2 emit by animals, but the point is that We have to grow more trees that we can counter effect the part of CO2.