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Some possible solutions to assist feeding the world in 2050 - part 1

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01 August 2015, at 12:00am

Dr TONY ANDREWS continues his discussion of the challenges facing food producers in feeding an everexpanding global population and offers a number of possible solutions in meeting them

IF the world is to feed itself in 2050 it will have to meet many challenges, both technical and political.

After land availability and suitable fresh water provision, the ability to reduce, manage and recycle human and animal faecal waste and food waste are major potential limiting factors to food production.

The land will need to be harvested with areas using crops suitable for each environment, and producing maximum yields. This will require suitable crop type with minimal and targeted water and fertiliser. More crops will be used as food and probably less for animal feed.

Attitudes to acceptance of some foods will need to change. Some areas will be best suited to pasture and for use by herbivores. Most animals will need to be intensively kept as this reduces land requirements, although some farms will still produce for niche markets.

Production per animal (milk, eggs, offspring) will need to increase and each animal will need to have increased longevity. Those used for meat will need to be grown with maximum feed conversion efficiency.

If problems with pollution and disease can be overcome, producing fish (sea and fresh water) and other types of aquaculture can probably be more easily increased than land production. Food waste needs to be reduced in less-developed countries by improving logistics and in the developed countries by improving dietary choices, reducing consumption, reducing waste and recycling food materials.

Harvest the land

The world’s available land mass will not increase. The area available for food production will decline because of climate change and housing the increasing global population.

To conserve land, concentrating population in cities, as is currently happening, will assist as will building upwards and not horizontally. There will be a need for increased water availability and this has been discussed in the previous article (Andrews, 2014). Suitable water supplies can allow production in otherwise infertile areas.

It was previously argued in another article that with co-operation it will be possible to feed the world’s population in 2050. However, the type of food provided is open to debate and will probably require change in eating habits in some or most countries. Attitudes to different foods may need to change locally in socio-economic, ethnic and national terms.

Growing and harvesting plants and cereals correctly could meet world needs if there is the political will to do it. The amount produced will probably need to double to meet the world’s requirements.

The cultivation of plants (cereals, rice, protein crops) to produce all food is feasible and it is suggested that it will not greatly increase the carbon or GHG footprint. It will require increased land use and also increased yields per unit of land. This will require use of more productive plant varieties and also, if the characteristics are right, it will probably include geneticallymodified (GM) plants and those produced by other technologies.

All plant types (conventional and GM) used need to be suitable for the area and the local environment. Ideally, where possible, crops should be grown which can be utilised by man and animals. As the climate alters, the varieties planted need to be altered in anticipation and in response to such changes. This is considered too optimistic by some who believe that climate change will restrict future yield growth. Whilst this may occur, it illustrates the need to produce local technical answers rather than global ones.

The challenge of producing sufficient food is going to be a massive problem. Using the production of wheat in the United Kingdom as an example, the current average yield per hectare is 8.4 tonnes. By about the year 2035 and using the same area for wheat production, it has been estimated that the wheat yield will need to increase to 20 tonnes/hectare.

This is 2.4 times the yields of today and to place this in perspective the current world record wheat yield is 15.6 tonnes per hectare, which was produced in New Zealand in 2010. It means an annual increase in wheat yield of towards a tonne, but calculations have predicted that the rise will only be 10% due to the increasing CO2 levels (Abel, 2014).

If some of these numbers are even roughly correct, it will mean the need for an increase in areas used for wheat production, greatly improved, suitable and effective technology, higher yielding plants (currently typical yield rise from plant breeding is 0.04% per year), effective pesticides and their intelligent targeted use, more efficient herbicides and their targeted use, efficient harvesting and storage of cereal and straw.

An example of perhaps a suitable technology might be the erection of multi-storeyed buildings in cities and elsewhere to maximise hydroponic (now sometimes called aquaponic) systems to rapidly produce large quantities of highly digestible plant crops for both man and animals.

Although not on the diet of many developed countries, the consumption of insects and some other invertebrates is already common. It can provide utilisable protein for people as well as producing large amounts, often from degrading or decaying animal or plant material.

There are those who will advocate us all becoming vegetarians and there are those who see some merit in the argument. In fact, the daily greenhouse gas (GHG) emission has recently been suggested for different UK consumer-types (high meat eaters 7.2kg CO2 equivalent; medium meat eaters 5.6; low meat eaters 4.7; fish eaters 3.9; vegetarians 3.8; vegans 2.9) (Scarborough and others, 2014).

However, despite this, man is designed as an omnivore and it is most unlikely that all will subscribe to a vegetarian diet. Trends at present suggest the reverse and although the assumption may not be completely correct, it is probable that consumption of animal food products will increase in most countries when economics permit it.

The extrapolations are based on changes occurring with a country’s increase in gross national production and this has previously been argued as unsustainable on a global basis. However, it is likely that, proportionally, global milk and egg consumption will rise faster than most types of meat intake.

There are some problems if the politicians consider that GHG emissions or carbon or other footprints are the main or only regulator of food production. The footprint models used tend to look at all the costs up until it reaches the kitchen. These do not necessarily take into account that inputs in the various parts of the food chain can be altered or often there are mitigating factors which may modify GHG or other factors which are not considered as being as important as the calculated footprints.

Thus, there are many areas where pasture is the most productive or only crop that can be successfully grown. If this is to be utilised effectively other than for fuel, then animal food production from herbivores will have a positive impact.

Harvest the sea

Salt water contained within the seas and oceans covers 71% of the earth’s surface. Only 3% of the world’s water is fresh and of this only 1% is available as liquid. Desalination was previously mentioned as one method to increase available fresh water: as almost all water is saline it would seem sensible, where possible, to make use of it. There is some potential to increase the harvesting of sea plants for fertiliser and food but the demand for the latter is currently likely to be limited.

Whilst there has been overfishing of many types of seafish, it is possible that fishing can continue sustainably with suitable regulation and enforcement. Some species are being heavily affected by climate change such as cod, which requires cold water for breeding and is moving north. Other fish, however, tend to encroach into new areas of warmer sea and these will need to be encouraged and harvested and human palates educated to accept them. Since the mid 1990s the world wild fish catch has levelled out at about 80 million tonnes annually. This is a large amount of fish and, even if it were sustainable, it would not meet the growing demand for fish.

Fish are very efficient converters of protein eaten into meat protein. Although fish farming in countries such as Scotland and Norway is widely known, currently China produces 61% of all of the world’s aquaculture.

Farming has produced problems with pollution and spread of disease to wild fish stock. The fish farming industry is well aware of these and is becoming better able to contain and prevent them. It is also an area where veterinarians can play an active role.

Already salmonid farming has been successfully undertaken and assisted in reducing the price of salmon and trout. Almost all salmon eaten these days in Britain and some other European countries has been farmed. Other species are starting to be farmed with variable success including barramundi, carp and tilapia. Catfish are commonly and easily reared in many parts of the world.

Other seafoods such as shrimps (40% consumed is farmed), oysters and mussels (12 million tonnes produced annually) are being successfully reared and then are consumed.

At present, aquaculture produces about 50 million tonnes annually but the knowledge and expertise is becoming available to increase this with potentially only a limited effect on the natural environment.

Besides saltwater fish, there is the potential to produce more freshwater fish. Farming of fish occurred over two millennia ago with the Chinese and Romans. It should be possible to integrate some of this with increased storage and distribution of water. Several species are farmed (such as trout and carp) but to introduce some new species, the public would require education in their eating habits.

If managed correctly, aquaculture has the potential to greatly increase food supplies of animal origin with less damage to the environment than from land-based animals and birds. Although many of the fish currently farmed are carnivores, other fish are vegetarians and breeds such as the tilapia are already being raised in South America and Asia. The use of these and other species overcomes some of the problems concerning some fish species being used as a protein source for other fishes.