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Several articles discuss plants in the context of providing critical biological energy as food, and social energy as fossil fuels. The overall Plant Big History context is addressed in the article Agraria. The origins of agriculture (the Neolithic Agricultural Revolution) article discusses the beginnings of farming, a theme that is extended in time to the present in an account of staple foods, given a more global context in the article on cultivated plant globalization.


Plants provide the food energy that sustains all life. Plant energy powers not only the bodies of all organisms as biological energy, it has also facilitated the historical human socio-cultural development that we associate with complex social organization. This began with the storable concentrated energy of cereal grains that resulted in the settled communities of the Neolithic Agricultural Revolution and led, eventually, to Bronze Age cities and civilizations. In the modern era it was the concentrated energy of fossil fuels that provided the social energy of the industrialization that produced a global economy.

Human bodies take from plants (ultimately) not only food energy sourced from the Sun, but carbohydrate, protein, edible fats and oils, vitamins and minerals that are vital for our existence.

Food production is fundamental to life and yet it is also the single most environmentally demanding aspect of our lives.

Globally, there are now about 3000 known food plants and, of these, about 150 have been widely cultivated and traded. In spite of this apparent variety about 90% of the human diet consists of only about 15 species and, of these, only 4 (wheat, rice, corn and potatoes) make up over 60% of the world’s food supply. We now rarely eat wild food (possibly a few berries, greens and mushrooms). It is these staple foods that now provide the crucial energy sustaining humanity, and these are discussed in a separate article dedicated to staple foods.

All staple foods were domesticated in prehistoric times and the full range of cereals, vegetables and fruits have been altered from wild ancestors. Regional agriculture evolved based on local plants: in East Asia this was rice, in the Middle East Wheat and barley, and in Central and South America maize.

Regional agriculture evolved based on local plants. In East Asia this was rice. in the Middle East, wheat and barley, in Central and South America, maize, and sorghum in Africa. All staple foods were domesticated in prehistoric times and the full range of cereals, vegetables and fruits are cultigens, that is, they are genetically different from their wild ancestors.

World population is expected to peak at around 11 billion in 2100. Arable land is becoming more scarce and food security is likely to become an increasingly important global issue. We must increase global food production while reducing its environmental footprint. The international Commission on Sustainable Agriculture and Climate Change recommends placing food security and sustainable agriculture within global and national policy frameworks with greater financial support, especially for populations and sectors that are most vulnerable; reducing waste; encouraging healthy and sustainable eating habits – which requires commitment across the globe.

Australia feeds 60 million people a year and is one of only 15 countries (there are 195 in the world) that export more food than it imports. There is a  rapidly growing population and a growing megalopolis along the east coast that will absorb increased production. Australia on average has the lowest rainfall of any country ending up in river systems with 89% of rainfall lost to evaporation. By 2020 climate change can cut river flows by 10-25% in some areas of southern Australia.

Agriculture and rangeland occupies about 40% of the surface of the Earth (57% of Australia) and food production consumes about 20% of the world’s total plant primary productivity.

Land use & primary productivity

Of all plant matter produced on the planet (total net primary productivity) about 20% is now for human use (crops, pasture, timber etc.). For figures below see. [2] For more data see plant biomass.

Agriculture                                     38%                57%
Arable land                                    11%                   6%
Permanent pasture                     26%                 51%
Permanent crops                           1%                    0.04%

Food & resource consumption

Agriculture impacts the natural environment by appropriating land formerly occupied by wild plants and animals. In general this has led to species extinction and land degradation but also further demand on natural resources that are needed to raise animals and crops, notably water, energy, and chemicals.

This call on resources can be measured in terms of our overall individual resource consumption that is related to food. In Australia, for example, this is 30% of our emissions, 46% of our water use, and 50% of our total Ecological Footprint.
We need to aim for low water; low materials; low or no chemicals; low energy (low carbon diet); and minimum impact on biodiversity. This is assisted by eating locally-produced food with a diet that is low in meat and dairy products.[1][4]

We need to aim for low water use; low materials; low or no chemicals; low energy (low carbon diet); and minimum impact on biodiversity. This is assisted by eating locally-produced food with a diet that is low in meat and dairy products.

Global poverty & food security

The United Nations Food and Agriculture Organisation (FAO) estimates that the total number of chronically undernourished people in the world in 2001-2003 was 854 million.

The FAO estimates that by 2030 about 50% more food than was produced in 1998 will be needed to feed the world population.

Agriculture is now planning for climate change with the expected inundation of coastal areas, changing of optimal crop growing regions due to altered rainfall and temperatures, as well as a redistribution of pests and diseases.

Here are six principles to help in making ethical food choices:

Transparency, we have the right to know how our food is produced

Fairness, producing food should not impose costs on others

Humanity, consider unnecessary suffering of animals

Social responsibility, workers are entitled to decent wages and working conditions

Environmental responsibility, use foods that have been produced with minimal impact on the environment

Needs, preserving life and health is more justified than other desires.

The Murray-Darling catchment is Australia’s ‘food basket’ as it produces 41% of the value of the country’s agricultural production and 71% of the nation’s total area of irrigated crops. Water shortages threaten both the food supply and the river ecosystem.

Food waste

At least 8% of food in Australia goes to waste. It is possible to use anaerobic digestion to recycle food wastes into energy and fertilizer thus contributing to the circular economy of nature, in which organic wastes are recycled into food and energy resources, thereby maximizing carbon sequestration and minimizing greenhouse emissions and environmental pollution. These processes are still in the early stages of development.

Food transport & world trade

Globalisation has resulted in increased food trade. In 2005 global food exports, valued at about US$612 billion, increased by 5% over the previous year and over 66% of this consisted of transformed or processed products. Ease of distribution and relatively cheap transport means that transnational companies can source the cheapest products from around the world. This has lead, in 2006, to the origin of the term ‘food miles’ which relates to fossil-fuel energy use in sending highly processed, canned and packaged food over ever-increasing distances, often under refrigeration and with various additives and preservatives. It has been criticized for food uniformity, vulnerability to disruptions, standards, the effect on small farmers and a distancing of consumers from the source of their sustenance.

In the US, the average food item travels 2500-4000 km. The first study in Australia was published by CERES, Melbourne, in July 2007. The total for all transport in a typical food basket (multiple items) of commonly available and popular foods was found to be 70,803 km. However, it is possible for products transported over long distances to be more energy efficient than the same product produced locally e.g. an out-of-season crop produced under glass in Australia may use more energy than the same long-distance food. ‘Food miles’ are only one component of the total proct resource use over its life cycle.

Sustainable agriculture

It is estimated that, in passing through the food chain of agribusiness, each calorie of food produced requires 10 calories of fossil fuel – fossil fuel energy. Use of Technology in developed countries has greatly reduced the numbers of people involved in food production. Mainstream agriculture has now boosted “sustainable” practices that address: desertification; salination; sodification; eutrophication; risk of disease in monocultures (genetically identical crops); methane production by livestock; high fossil-fuel energy machinery; loss of arable land.

Though the monitoring of this situation has vastly improved over the last decade or two much needs to be done to increase food production while reducing its footprint by using land more efficiently, increasing cropping efficiency, changing diets, and reducing waste.[3]

Urban agriculture

Cities are often built on prime arable now covered with buildings and bitumen. The remaining open space offers opportunities for food production in home and community gardens, as street trees, green roofs, green walls, aquaponics & hydroponics. This urban “farming” not only provides sustenance but “greens” the concrete jungle and moderates the climate. It can be distributed through food exchanges, cooperatives, farmers markets and the like contributing to the local economy.

Local food

Locally grown food can significantly reduce our individual Ecological Footprint because: potentially saves land and biodiversity; saves resources (water, energy, materials) embodied in agribusiness (cultivation, storage and refrigeration, transport, packaging, marketing, retail, infrastructure, administration) – any excess food can be distributed to those in need; reduces use of fertilisers and herbicides and GM organisms. Minimises waste. Means we are in control of all stages of production, distribution and consumption. This helps with any health concerns and the fact that there are no internationally agreed environmental and work standards.

We have control over the kinds of food you eat, hygiene (does not need to be fumigated, refrigerated, processed or packaged), chemical inputs and social justice issues relating to production, distribution and administration.
Locally-produced food is fresh and often tastier; growing it provides light exercise; awareness of natural cycles – seasonal cycle, biological cycle of birth, growth, maturation, death, decay and renewal; awareness of ecological processes; possibly a family or social activity encouraging children to eat healthy foods. Greater choice of varieties. Instant contact between grower and eater. (Horticultural therapy)

Sustainable eating

We must all live and flourish, but we must do so with the awareness that the agriculture that sustains us is bought at a price that includes resource depletion of many kinds, including the loss of species. Our aim is to monitor and minimize these costs.

We can define a sustainable diet as one that promotes health and wellbeing while minimizing negative economic, social and environmental impacts.

As a starting point this means a diet that includes no, or minimal red meat. If meat is non-negotiable then select, preferably, white meat and fish.

Grow your own food

1. Remember: environmental degradation springs essentially from consumption of resources. If you are self-sufficient, you are making no demand on external resources

2. Be aware of the energy, materials, water, biodiversity and social costs of your garden activities

3. Propagate from your own plants (seed & cuttings) where possible; share seed and produce with neighbours; prepare for leaner times by preserving and storing in times of abundance (see specific growing suggestions)

ENERGY – maximise the capture of the Sun’s energy by growing energy-rich and high yielding crops like pumpkins and potatoes.

MATERIALS – minimize use of materials and chemicals and use integrated pest management.

WATER – use water from a rainwater tank harvested from the roof.

BIODIVERSITY – integrate garden activities as far as possible with the surrounding environment, in particular, avoid weedy invasive plants


Buying food

1. Remember: environmental degradation springs essentially from consumption of resources. Be as aware as possible of the energy, materials, water, biodiversity and social costs of food production

2. Buy organic, Fair trade, be mindful of ‘food miles’, buy bulk, buy with minimum packaging

First published on the internet – 1 March 2019
. . . 13 December 2022 – revised


Plant-People Big History
Courtesy Rob Cross – 2017

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The energy derived from the Sun, stored in plant tissue during photosynthesis, then used (as food) to power the bodies of living organisms. Most biological energy drives internal metabolic processes within organisms but some is transformed directly into social energy via muscles and brains.

The food energy needed to sustain an individual human body has remained about the same throughout history (though physically active people require more calories) at about 12,500 kJ. while the human body has an energy generating capacity (at basal metabolic rate) of around 80 watts (about 20 watts of this being used by the brain), about the same as an incandescent light bulb). To derive a physical 'feel' for what this means, a 100 watt light bulb works 1.25 times harder than our body, that is, 1.25 H-e or 1.25 human equivalents.


The energy that powers the social activity that may be directed towards the maintenance or enhancement of social organization.

The energy of human social activity is derived partly from the biological energy that powers human bodies, and partly from external sources like water, wind, animal muscle, fire and more recently, fossil fuels, nuclear fuels etc.

Historically, the proportion of social energy derived from human bodies has decreased over time to become negligeable today. Fossil fuels provided a concentrated, abundant, and cheap source of social energy that facilitated growth in populations and economies. The use of this energy has been leveraged by the increasing efficiency of technology as both material and mental tools.




Daily food needs - 1500-2000


   Natura       -     5000-10,000
   Agraria       -    10,000-30,000
   Industria    -    200-230,000
   Informatia  -   200,000 +



Date of origin

Base state   -       human muscle

Hand tools        -     3.5 M BP
Mental tools     -     3.5 M BP



Fire                     -     1.7-2 M BP
Animal muscle -     12000 BP
Wind & water   -  ...  5000 BP ...
Coal                    -      1600 ...
Gas                     -      1820 ...
Oil                       -      1860 ...
Electricity           -      1880 ...
Nuclear              -      1950 ...

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