Rabbits love farms
The Green Revolution in Farming
- In the 1960's the farming practises changed with the addition of synthetic fertilise and pesticide sprays. This significantly boosted agricultural outputs.
- However these modern agricultural practises also lost valuable carbon from soils and contributed to additional emissions of methane nitrous oxide gases, both potent greenhouse gases.
- Today, the agriculture and food systems contribute to 14% of all GHG emissions in Australia and 20% globally. [1]
Emissions from livestock
- 70% of the emissions from agriculture come from ruminant meat (cattle, sheep)
- This is because bacteria in the digestive tracts of these animals ferment feed into methane gas.
- In the short term methane gas is 30 times more potent than CO2 in terms of its greenhouse potency.
- To reduce emissions from this sector large dietary changes will be required.
Rice and GHG emissions
- Not all vegetable based diets are the same.
- 14% of total agricultural emissions come from rice.
- Flooded paddy fields results in the rotting of organic material which releases methane.
Fossil Fuels in Farming
- There is a reason why 70% of people in India live and work on farms and why only 3% of Americans work on farms.
- The reason is that Americans (and Australians) use large amounts of energy (fossil fuels mainly) in agriculture to produce fertiliser, build and run farm machinery and transport and store produce.
- In America, thousands of units of energy from fossil fuels have been used to replace human labour [2].
- But if energy costs were to increase, or if the use of fossil fuel energy were restricted, then high energy processes rapidly become more expensive (and less profitable).
- By contrast, more manually run process with little fossil fuel energy inputs are unaffected.
- This relationship is illustrated in the chart below that shows the price sensitivity of different milking process relative to the cost of electricity.
- Take away cheap fossil fuels and even the simplest renewable energy asset becomes prohibitively expensive to produce.
Natural Gas and Synthetic Nitrogen Fertilizers
- Nitrogen fertilisers are produced from ammonia, and ammonia is produced from natural gas using the Haber process [3]
- Natural gas (CH4) is used to provide heat and Hydrogen atoms for the process.
- The production of Nitrogen Fertilizers is very energy intensive and produces significant CO2 emissions.
- Also, if too much nitrogen is applied to soils it may result in the release of Nitrous Oxide (N2O), a powerful greenhouse gas [4].
- Excess nitrogen based fertilisers also contribute to algal blooms in waterways (a process called eutrophication)
- Nitrogen fertilizer have supported the industrialisation of agriculture.
Energy Inputs and Energy Outputs from Agriculture
Carbon emissions from a different Protein Sources
- It is possible to compare the carbon emissions from different sources of protein [5].
- The average adult requires 60g of protein per day as part of a normal diet (21,900 g protein/year).
- Using the information in the chart we can calculation CO2e emissions per year based on protein consumption.
- Plant based foods have lower carbon emissions.
- Tofu 1.6 kg/100g protein - (1.6 kg x 219 = 350.4 kg CO2e/year
- Beans 0.65 kg/100g protein - (0.65 kg x 219 = 142.4 kg CO2e/year
- Peas 0.36 kg/100g - (0.36 kg x 219 = 78.8 kg CO2e/year
- Nuts -0.8 kg/100g - (-0.8 kg x 219) = -175.2 kg CO2e/year - negative emissions because trees are replacing annual crops.
- Animal based diets have higher CO2e emissions, but this varies significantly within and between different sources of meat.
- Farmed fish 3.5 kg/100g = 766 kg CO2e/year
- Eggs 3.8 kg/100g = 832 kg CO2e/year
- Chicken 4.3 kg/100g = 941 kg CO2e/year
- Pork 6.5 kg/100g = 1,423 kg CO2e/year
- Cheese 8.4 kg/100g = 1,839 kg CO2e/year
- Farmed shrimp 10 kg/100g = 2,190 kg CO2e/year
- Lamb 20 kg/100g = 4,380 kg CO2e/year
- Beef 25 kg/100g = 5,475 kg CO2e/year
- If we assume that agriculture and food represent 14% of Australia's GHG emissions, and we need to reduce our emissions from 15 tonnes per person per year to 1 tonne per person, then the permitted carbon budget for the agriculture sector is 1 tonne x 14% = 140kg per person per year
- With regards to lowering GHG emissions, the biggest difference we can make is to eat more plant-based sources of protein such as tofu, nuts, peas, and beans.
- Low emission animals meats could still be eaten occasionally (small amounts weekly and monthly).
- Keeping chickens that produce eggs would have lower emissions that the data published in this study because their production is less intensive. They would be excellent protein producers in an urban setting.
Melbourne's Foodprint
- The Greenhouse gas emissions from commercial food production in and around Melbourne was published in 2016 [6].
- Melbourne’s food consumption accounts for over 0.9 tonnes CO2e per person per year.
- This only accounts for emissions up to the farm gate and does not include emissions generated in the processing, refrigeration, transport, cooking or waste of food and will therefore significantly underestimate the total GHG emissions associated with the food industry.
- This figure does not consider GHG emission contributions from foods imported from outside Melbourne.
- The GHG emissions can be broken down by food group. Beef, lamb and diary are the biggest GHG contributors.
- 57.8% GHG emissions from beef and lamb
- 20.9% GHG emissions form dairy
- Based on this study, to reduce GHG emissions from 900 kg/person/year to 140 kg/person/year
Fossil Fuels are coming to an End
- This graph shows the availability of different oil deposits in the USA from 1900 to 2015 [7].
- The graph on the left shows total oil production in the USA. There is one peak in 1970 and another larger peak in 2015. It implies the the USA is more independent of energy imports, because it can produce so much of its own oil.
- The graph on the right show the breakdown in oil contributions.
- Conventional oil peaked in 1971 and has been in decline ever since. This oil is relatively easy to extract and kept oil costs low.
- Alaskan oil was then extracted followed by deep water oil in the Gulf of Mexico Deepwater Horizon film
- The USA is now extracting so-called tight oil which comes form rock substrate and is more expensive again to extract.
- Other sources of oil or conversion process for oil may be found, but most will be more expensive and will not address the environmental issues associated with the release of CO2 emissions.
- Above all, when the use of fossil fuels starts to decline this will have negative repercussions on the global economy.
The Carbon Pulse
- We are living in the middle of a Carbon Pulse.
- The Carbon Pulse can more easily be seen on this 10,000 year time chart.
- The Carbon pulse represents our use of fossil fuels which are a limited resource.
- We will need to wean ourselves off fossil fuels to help minimise the environmental and social consequence related to Climate Change.
Fields to Farms
- Melbourne has lots of opportunities to retain open areas and partly convert them to productive spaces such as farms.
- Food waste, water and human labour can all be inputs to these farms.
- The outputs would be native gardens, food produce and local employment.
- If farms are managed using Regenerative Farming or Permaculture practises then net CO2 emissions will be low and sometimes even negative [8]
Roads will become Stranded Assets
- If we convert a open field to a freeway we have doomed that land to a perpetual dessert.
- Bitumen will cover the fertile ground. Rainwater will be diverted away from the land.
- In the heat of summer the area will be suffer from higher urban temperatures due to the Urban Heat Island Effect.
- The transport envisioned for the road will not materialise, because of the need to reduce CO2 emissions.
- The road will become a stranded asset.
- Don't build roads. Instead build farms, nature reserves and active transport corridors.
A Sense of Urgency
- We need to start preparing for urban farming now, because it takes up to 5-10 years before farms become productive.
- This is because:
- Fruit and nut trees take 3-5 years before they start producing fruit.
- Poor soil takes time to improve with organic inputs, minerals and cover crops.
- Learning new environmentally sustainable gardening techniques will take time to master.
- There will be shortages of seed and plant stocks that will take additional time to cultivate.
- There may be a drought or extreme heat events that may cause set-backs.
- New urban gardening plots will need to be allocated to communities.
Start the Journey Now
- Here are some simple strategies to help you get started on to prepare for urban agriculture:
- Complete the Urban Farming course at CERES
- Join a local community garden and learn from experienced gardeners.
- Practise gardening at home each day.
- Install a large (6-10,000 litre) rainwater tank with pump to water the garden. Learn the maintain the tank and roof.
- Plant fruit trees and nut trees.
- Plant native plants to provide habitat for native animals (mostly small animals).
- Experiment with growing vegetables.
- Buy appropriate gardening tools (good quality hand tools)
- Learn to compost all organic waste in compost bays.
- Keep chickens or rabbits as pets.
- Eat less meat and dairy.
- Learn to preserve your produce (air drying, fermenting, passata)
- Learn to garden like a Nonno [9]
