UK GCSE level age ~14-16, ~US grades 9-10 Biology revision notes re-edit 11/05/2023 [SEARCH]

 Food: 3. What threatens food security?

Potential problems to increasing food production for the rapidly growing population

Doc Brown's Biology exam study revision notes

There are various sections to work through, after 1 they can be read and studied in any order.

INDEX of biology notes on population growth, food security, sustainability and food production


3. What threatens food security?

What threatens increasing necessary food production?

Problems facing us in tackling food insecurity and increasing sustainable and environmentally food production

The UN estimates from ~2025 onwards

 (i) there could be nearly 1 billion people suffering from food insecurity i.e. undernourished with their health at risk,

(ii) and food production needs to be increased by 60% by 2050 to meet the increase in population number estimated to be 10 billion by then.

In the sections, in no particular order of priority, I've discussed various issues concerning the difficulties that will, and are, being encountered in trying to feed everyone on the planet adequately.


(a) Birth rate and rapidly rising population

The world's population keeps on increasing with high birth rates, particularly increasing in developing countries, which are also often the poorest and least able to provide food security for all of their populations.

It will not easy for the current agricultural systems to keep pace with the rate of increase in the world population.

As people get more affluent their diet changes to a wider variety of foods, usually involving more expensive items like meat and fish.

The production of meat is via a food chain that involves a lot of energy usage and loss of biomass.

Per unit area of land, you can produce more food from crops than grazing animals.

It should also be noted that animals and fish on farms are often fed supplementary food based on crops, adding to the inefficiency of animal food production.


(b) Farming - problems with agriculture - pathogens

Farming is affected by insect pests, weeds, fungi and pathogens like bacteria and viruses, and growing monoculture crops on the same land is reducing biodiversity.

Any new infestation of pests (including locusts) and pathogens will reduce crop yields.

The plants gene pool may not cope with a new disease and the lack of 'genetic resistance' means many plants will become diseased and damaged sufficiently to reduce crop yields of saleable edible food.

This requires the application of expensive insecticides, herbicides and fungicides or using GM products to maintain high crop yields, but then its difficult to avoid environmental damage.

New pests and pathogens are always emerging to affect farming - reducing crop yields.

Many crops are 'monocultures', just one species of plant, this considerably reduces biodiversity and the use of pesticides (insecticides and herbicides) has considerably reduced the numbers of pollinating insect, either through poisoning or lack of food - nectar.


(c) Farming and environmental conditions

Agriculture is greatly affected by environmental conditions e.g. the local weather, particularly drought conditions from lack of rain leading to reduced yields and total crop failure - global warming won't help!

This often happens in hot dry countries where the greatest state of food insecurity exists.

The food security targets may well become more difficult to achieve with climate change.

Any change in the climate can affect growth patterns of crops, with both positive (perhaps increased yields in a warmer/wetter climate) and negative consequences (famine as a result of drought and good soil blown away).

See Greenhouse effect, global warming, climate change from fossil fuel burning

and section (k) below on climate change


(d) Quality of soil

Poor quality soil lacking in nutrients or water means crops will fail, even if they are GM.

The quality of soil initially depends on the local geology, but the weather and climate change will have their effects e.g. heavy rain can wash fertile soil away.

Any form of soil pollution will affect the growth of crops reducing fertility of the soil and reducing yields.

Soil contamination is caused by the presence of various human-made chemicals. It is often caused by industrial activity e.g. factories or mining, agricultural chemicals or improper disposal of waste. The most common chemicals involved in pollution are hydrocarbons, solvents, pesticides, lead, and other heavy metals.


(e) A wealth factor

The richer developed countries able to buy and import selected food products from poorer countries.

But the purchase of exports from poorer countries means there is less food available to feed the indigenous population - 'cash crops' for export brings in much needed revenue but leads to food scarcity for the poorest people - who are often the ones growing the crops!

At the same time, as people become wealthier in developing countries, demands for a wider variety of foods in their diet will increase e.g. more expensive fish and meat and this increases food production pressure and doesn't help food security for many other less wealthy people.

The people of poorer countries are not able to afford the cost of importing agricultural products.

See section (h) on biomass because cattle is an inefficient way of 'growing' food.


(f) Cost of agriculture to the poor

The poorest countries with the greatest food needs are also the least able to afford the initially high costs of farming.

You need expensive fertilisers, machinery and fuel, livestock, seeds (GM and non-GM) plus pest control systems to sustain any significant agricultural production.

This makes it difficult for poorer less developed countries to produce enough food to feed their own populations.

It also means that if its costly to produce food, the price at the market place increases - the poorer you are less food you can buy and perhaps of less quality too.

Many richer countries give aid to poorer countries, and long may it be so, but politics and globalisation economics don't always help!


(g) Political unrest

Poorer underdeveloped countries, particularly in Africa, but not exclusively, suffer from the effects of political unrest including civil war and terrorist group activity.

Economic interests, including mining and water, are fought over.

Any lack of political stability in a country makes it difficult to retain the constant agricultural production of much needed food for the people.

In times of civil unrest, and even worse in a civil war, important infrastructures breakdown e.g. lack or organisation and transport for distributing food and medical supplies.


(h) Biomass and food chain considerations

As you move up a food chain you lose energy and biomass at every stage.

See Food chains, food webs, trophic levels and biomass

Therefore, for a given area of land, you can produce more crops for food than rearing animals on the same land - which often need extra food from crops or other animals!

Crops, primary producers using photosynthesis, are more efficient producers of food than livestock.

Many farm animals and fish are partly reared on grain (e.g. corn, oats) that could have been used for food - and to make matters even less efficient, part of reared livestock and fish diets are supplemented with protein food derived from other animals.


(i) Biofuels

Crops are being grown to partly replace fossil by converting plant material into biofuels.

The idea is to replace non-renewable fossil fuels from oil and gas with renewable plant based fuels - like bioethanol, made by fermenting processed sugar cane and other carbohydrate rich crops.

Unfortunately this uses land that could be otherwise used for growing food crops for 'human consumption' - not for fuelling road vehicles!

Wealthy countries can have the capital to buy cheap organic crops to convert to biofuels, at the expense of the less rich people of a poorer developing country.


(a) to (i) are very much about growing crops of edible grain or vegetables and raising cattle for milk or meat, but fish is a very important source of food (protein, essential oils and vitamins).


(j) Fishing

Unfortunately in many parts of the world fish stocks are declining due to over fishing, particularly if unrestricted.

We can be talking about lakes, seas or oceans, and if you take out too many fish too quickly, there is not sufficient time for enough fish to reproduce and grow into adult fish.

Overfishing, especially of young fish prior to reproducing, means food chains are disrupted and we run the risk of species of fish disappearing from lakes, seas, and areas of the oceans.

There are plenty stretches of water on the planet were fish stocks have decreased to very low non-sustainable levels.


(k) Climate Change - causing significant environmental changes

Know and understand that levels of carbon dioxide and methane in the atmosphere are increasing and contribute to ‘global warming’. These two gases are known as 'greenhouse gases' because they reabsorb infrared radiation radiated from the Earth's surface, which of course is heated directly by solar radiation, so the atmosphere acts as an insulation layer like the glass panes of a greenhouse.

Know and understand that an increase in the Earth’s temperature of only a few degrees Celsius and is likely to cause 'climate change':

Climate change may cause big changes in the Earth’s climate, there is more thermal energy in the Earth's weather system, this may cause eg more violent hurricanes, areas of drought, in other words, quite significant climate changes with different effects in different parts of the world.

  • e.g. in Africa, the Sahara desert is increasing in area, reducing land for farming, reducing food production capacity in either growing crops or razing cattle.

  • There is some evidence that natural disasters like storms and flooding are increasing due to global warming.

  • Climate change may cause a rise in sea level from thermal expansion and melting land ice leading to flooding of low lying coastal areas - maybe areas of food production like rice.

  • Climate change may reduce biodiversity, e.g. temperature changes may affect a particular species which may lead to the drastic decline of a plant or animal species in a particular area.

  • Climate change may cause changes in migration patterns, eg in birds.

  • Climate change may result in changes in the distribution of species e.g. change in temperature or pH of the seas and oceans can have a profound effect on local populations of marine organisms (plants or animals which maybe sources of food).

    • If an area becomes warmer in the northern hemisphere, then particular animals may migrate north to find a cooler region to which they are accustomed.

    • If more carbon dioxide dissolves in the oceans, they become slightly more acidic and maybe too acidic (pH falls) for certain species to survive.

    • Similarly, a warmer ocean maybe to warm for species to survive eg coral and its complex colonies of plants and animals is very susceptible to pH and temperature changes in the ocean.

  • Know and understand that carbon dioxide can be sequestered in oceans, lakes and ponds and this is an important factor in removing carbon dioxide from the atmosphere.

    • Carbon dioxide is slightly soluble in water and so is readily absorbed by any water.

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