3. What threatens food security?
Potential problems to increasing food production for the rapidly growing
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.
of biology notes on population growth, food security, sustainability and
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
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
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
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).
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
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 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
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
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
Economic interests, including mining and
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
(h) Biomass and food chain considerations
As you move up a food chain you lose
energy and biomass at every stage.
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
Crops, primary producers using
photosynthesis, are more efficient producers of food than
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.
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).
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
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
(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
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
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
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.
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