Friday, November 09, 2007

Can we Feed the World?

The world population of 6.5 billion is projected to rise to perhaps 8 - 9 billion by 2050. Simultaneously this period corresponds to the Oil Dearth Era, the inevitable consequence of the peak in oil production "peak oil" which is due any time soon, if it has not already occurred. Since much of modern agriculture relies on oil, the question begs of whether we will be able to feed such a swelling population, and if so by what means, or what manner of readjustments might prove necessary to meet the task?

The term "organic farming" is a recent innovation, as opposed to its practices per se, which were those of the world's agriculture prior to the post WWII period, when chemical fertilizers were introduced to the soil. Until then, all farming was "organic" and was done without the employment of artificial "nitrogen" from ammonia or involving the routine use of synthetic pesticides. Modern "intensive farming" methods, such as we rely on in the industrialised nations, have been costed to consume 10 calories of energy in the form of fossil fuel (to provide fertilisers, pesticides and transportation fuel) for each calorie of energy that is recovered from the food itself.

Now, a strategy of localisation will inevitably reduce the contribution from transportation fuel, which is significant, but if pesticides and fertilisers are cut-out too, crop yields fall appreciably, meaning that fewer people can be fed per acre or hectare of arable land. It is a truth that "organic" farming is far more intensive in terms of land, if not in terms of energy. A major driver for the development of "chemical" farming methods was the plenty of chemical materials produced with the intention of military use during the war, and which it was decided could be put to benefit by turning them into agrochemicals.

I have mentioned Thomas (Robert) Malthus previously, who predicted more than 200 years ago that because population grew at a geometric rate (i.e. 2, 4, 8, 16...) but food production increased arithmetically (i.e. 1, 2, 3, 4...), the rate of reproduction would outstrip that of its sustenance, leading to mass starvation and an effective die-off scenario. This did not happen, in consequence of the "green revolution", which ironically is the opposite of the modern "green movement" since it refers to the many developments in agricultural technique that have been implemented since the 1960's, including the use of chemical additives to soil and to the produce grown on it. In consequence, world food production swayed-in with an increase of 250%, from greater absorption of nitrogen than occurs naturally, the growth of selected high-yielding crops like wheat and corn, and a greater mass of grain in the plants overall. For example, in 1950, an acre of land produced around 400 kg of wheat, but by 1950 this had risen to around 2000 kg/acre in South Asia but 4000 kg/acre in Europe and the US.

The downside of this is that it is necessary to provide more irrigation and hence an intensive infrastructure of dams and water-channels are necessary, especially to provide sufficient water during the winter period in order to grow an additional annual crop. Additionally, because more of the plant is consumed by humans, there is less residue left from it for animal feed. A mean energy intake for a human adult is reckoned at 2500 Calories (kilocalories) per day. A balanced diet is believed to correspond to about 60% carbohydrates, 12% protein and 28% fat. It is significant that during the green revolution the world has eaten more meat, meaning that the per capita land requirement is greater than would be the case to feed vegetarians. It has been estimated that 20 people can live entirely without animal products on the same area of land required by a typical meat eater. This may be a considerable overestimate, but certainly the carrying capacity of the earth is reduced if many of its inhabitants eat much more meat than they once did.

According to one calculation [1], the amount of land required to feed a single human is about one acre, following a mainly agrarian lifestyle, i.e. on the basis of pre-green revolution farming, without chemical enhancers. Since the total land area of the earth is about 150 million square kilometers, of which 10% is suitable for growing grains, another 10% for grazing animals on and a further 20% in the form of forests where animals can be raised, it may be deduced as a simple total that the sustainable world human population is:

150 x 10^6 x 100 hectares^2/km^2 x 40% x 2.47 acres/hectare x 1 acre/person = 14.8 billion.

However, the primary energy (food) input is surely the growing and grazing on a total of 20% of the planetary surface (we can't eat trees, although animals such as pigs can grub around the forest floor), suggesting a maximum sustainable population of nearer 7.4 billion, which is way short of the 8 - 9 billion presumed by 2050 and that contemporary farming methods will continue in perpetuity. Certainly there are other species on the planet, that do not exist purely in the interests of supporting the human race and the earth must support them too. So, would 30% of that land resource available for humans be a reasonable estimate? That leaves us with about
2.2 billion as the carrying capacity.

I am depressed. Either we will need to maintain the basic "forced methods" for crops by some means other than oil (and gas), to keep the present level of agriculture going (how?? coal??), or there will be a die-off in the world population, presumably through famine and wars over declining resources. Probably we will need to provide more of our diet directly from crops, rather than processing it through animals first, but even then, that only saves us perhaps a quarter-acre (from the per capita one acre), meaning the planet might support a maximum 3 billion, or less than half the present number. However, can we thus provide sufficient daily calories to fuel a population living far less sedentary lives, by grains etc. alone? There are just too many of us.

Related Reading.
[1] "The World's Expected carrying capacity in a Post Industrial Agrarian Society."
[2] "Human Appropriation of the World's Food Supply."


Anonymous said...

My wife says I should stop reading about stuff like this because it freaks her out when I scare her with my propaganda.

I'm beginning to think she's right.

My car is currently broken, and I feel like I should fix it in a hurry before we run out of oil. heh.

Professor Chris Rhodes said...

I know what you mean! I would feel happier in the camp of "deniers" and I hope that some new resource/ technology or whatever else will come to our rescue, but I can't see one on its way.

Most of the population increase has taken place in the developing world, so the UK population is just about half as much again is it was in 1900, but in Asia and South America it is nearer three times what it was then.

Hence, I think this is where the greatest die-off will occur, but this is a world problem, and rather than everyone attaining a Western lifestyle, the West will move toward an agrarian society, eventually, at least those who survive.

It is the transition from now to then that is the truly fearful aspect.

It's not a pretty thought!


Anonymous said...

Hello! Please see below:

The Vertical Farm Project - Agriculture for the 21st Century and Beyond... []
From the page: "It took humans 10,000 years to learn how to grow most of the crops we now take for granted. Along the way, we despoiled most of the land we worked, often turning verdant, natural ecozones into semi-arid deserts. Within that same time frame, we evolved into an urban species, in which 60% of the human population now lives vertically in cities. This means that, for the majority, we humans are protected against the elements, yet we subject our food-bearing plants to the rigors of the great outdoors and can do no more than hope for a good weather year. However, more often than not now, due to a rapidly changing climate regime, that is not what follows. Massive floods, protracted droughts, class 4-5 hurricanes, and severe monsoons take their toll each year, destroying millions of tons of valuable crops. Don't our harvestable plants deserve the same level of comfort and protection that we now enjoy? The time is at hand for us to learn how to safely grow our food inside environmentally controlled multistory buildings within urban centers. If we do not, then in just another 50 years, the next 3 billion people will surely go hungry, and the world will become a much more unpleasant place in which to live.

Why is Urban Agriculture important? | RUAF - Resource Centres on Urban Agri []
From the page: "Why is Urban Agriculture important?

Read more: Further reading

The rapid urbanization that is taking place goes together with a rapid increase in urban poverty and urban food insecurity. By 2020 the developing countries of Africa, Asia, and Latin America will be home to some 75% of all urban dwellers, and to eight of the anticipated nine mega-cities with populations in excess of 20 million. It is expected that by 2020, 85% of the poor in Latin America, and about 40-45% of the poor in Africa and Asia will be concentrated in towns and cities.
Most cities in developing countries have great difficulties to cope with this development and are unable to create sufficient formal employment opportunities for the poor. They also have increasing problems with the disposal of urban wastes and waste water and maintaining air and river water quality.

Urban agriculture provides a complementary strategy to reduce urban poverty and food insecurity and enhance urban environmental management. Urban agriculture plays an important role in enhancing urban food security since the costs of supplying and distributing food to urban areas based on rural production and imports continue to increase, and do not satisfy the demand, especially of the poorer sectors of the population. Next to food security, urban agriculture contributes to local economic development, poverty alleviation and social inclusion of the urban poor and women in particular, as well as to the greening of the city and the productive reuse of urban wastes (see below for further explanations and examples).

The importance of urban agriculture is increasingly being recognised by international organisations like UNCED (Agenda 21), UNCHS (Habitat), FAO (World Food and Agriculture Organisation), and CGIAR (international agricultural research centres). "

Just to name a few sites.

Unknown said...

This 'modern agriculture relies on oil' meme is just plain false. It relies on hydrogen for ammonia production which is produced from natural gas and coal, and can easily be produced from nuclear and solar power.

We aren't even close to the ceiling yet.

Professor Chris Rhodes said...

So what do we put into tractors etc.? Diesel from oil. I see where you are coming from re. manufacture of ammonia from H2 from natural gas (coal? Not so much as yet, surely?, though we could make it that way, and in the US you probably will given the huge resource there is there of coal).

The oil-crunch will hit all forms of transportation and machinery (including farm-machinery) driven by oil.

Food will get increasingly expensive, e.g. on tar-sand oil or that from CTL.

I give it 5 years max. before the poorest begin to starve.

Anonymous said...

An interesting article but you seem to have completely overlooked the natural or otherwise food resources from the world's oceans...

Propaganda is dangerous because it invariably only shows one side of the coin.

Professor Chris Rhodes said...

Food from the oceans? I like this idea! Do you mean plankton/microalgae as well as fish etc.?

Do yo have any sums for what might be got?

The only problem that strikes me immediately is that relatively local regions might have to be harvested (eventually anyway) as fuel for transport, processing, fishing and plankton harvesting runs short.

There is work being done on microalgae for food and indeed such is commercially incorporated into foods in various ways.

My point overall is that we will be pushed to use conventional land-based agriculture to feed us all.

A worthy comment to make and thanks - keep them coming! In terms of food and energy I think we will need all sources we can lay our hands on.



Anonymous said...

Further to my last point I will also say that if one subscribes to the theory that ice caps and melting and thus land area is decreasing and, consequently, water area is increasing, then the importance of food resources from the sea will become evermore valuable. Solar powered water farms are the one solution I can think of at the moment. Feel free to quote me. Ash

Professor Chris Rhodes said...

Hello Ash,

interesting what you say, and a valid point. I am just reading about growing seaweed offshore and maybe harvesting that for food?



Anonymous said...

The Chinese, Japanese and probably many other people have been eating seaweed for thousands of years - why not grow and harvest more - not to mention the edible animals within the seaweed using it as a habitat...

Dried seaweed tastes good, too.

Professor Chris Rhodes said...

A very interesting thought. In principle we could use "seaweed" - microalgae and macroalgae (i.e. what turns up on the beach), to generate both food and fuel. It has to be worth considering but so does population limitation.
But in order to secure the latter, we need a security so that you don't have to have 10 kids because half of them will die and you won't be able to run the farm.

The world lacks this assurance at the moment and yet it would be so easy to provide.


Chris Rhodes.

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