Emissions.

Latest Update 24th April 2020.
 
Carbon Dioxide (CO2) although not the most active of all the greenhouse gasses, is the most influential (by sheer volume), and the one growing in volume most rapidly. Its natural to have greenhouse gasses in the atmosphere and they are part of the carbon cycle on which virtually all Earth's life forms depend. We also depend on them to regulate the earth's surface temperature.

As the graph above illustrates, a rapid increase in greenhouse gas concentration (especially CO2) has caused a major change in the rate of heating of the planet's surface and atmosphere over the last almost 40 years.

These increased emissions seem to be coming from 2 main sources:- 

1.     Fossil fuels

 

They are extracted from underground and are used to provide power and raw materials for the power generation, transport, manufacturing, agricultural, retail, domestic, education, sporting, communications, arts and services sectors. Bye products resulting from their use include CO2 and other greenhouse gasses which find their way into our atmosphere.

These hydrocarbon materials are a finite resource, and as well as being a major factor in our dangerous build up of greenhouse gasses in the atmosphere, they will eventually become too hard and expensive to extract and process.

Fossil fuels support the life style we know today, and it will be incredibly difficult to make the shift to a new paradigm based on renewables from one that has taken nearly 200 years to establish. However, it has to be done, and quickly, if we are to avert disaster. 

Australia's Chief Scientist Dr Alan Finkel recently (Feb 12th 2020) addressed the Australian National Press Club. On the whole I found it uplifting, at least someone close to government knew what he was talking about. The references to moving from coal to natural gas as a first step towards sustainable power generation seemed sensible to me (New natural gas installations emit CO2 at a rate less than half that of new coal fired power stations as the technology stands today) . 

Realistically we can't just shut down all our coal power stations overnight without replacing them with something else, and stand alone wind and solar wont cut it because of the intermittent nature of their main power sources (wind and sunshine). I believe our main focus should be on growing solar and wind generation as fast as possible, and at the same time build massive batteries or green  hydrogen powered generators to fill in the gaps. I understand that power plants designed to use green hydrogen to generate electricity are, unlike coal, responsive to sudden changes in demand. They can be shut down and restarted at short notice. 

Hydrogen looks like being an ideal solution to this gap in power supply in the long run, provided it is produced by renewable electricity supplied by a system with capacity to spare in favourable conditions. It emits water vapour when used to generate electricity which is considered harmless when discharged to the atmosphere. The process is still under development at the scales required in this role, so natural gas will probably need to carry the load initially. Base load power provided by batteries might be compromised at the scale required because of limited supplies of Lithium (an important component in state of the art batteries).

I have been interested in hydrogen powered electric vehicles for some time, and Dr Finkle mentioned that major vehicle manufacturers are pursuing this avenue with some urgency. Development of battery storage for electric vehicles will no doubt continue, and electric vehicles may be offered with either hydrogen cell or battery storage for their electric motors, well into the future. Either would be sustainable provided the original source of the electricity and the materials used in manufacture are sustainable and non polluting. 

2. Reduction of biomass in our soils, grasslands and forests.

Before human intervention, earth's soils were deep and rich in biomass. Interactions between plants, animals and microorganisms in the soil were vigorous and in perfect balance (see Soil Foodweb) .

In modern agriculture, crop residues are no longer returned to the ground, and synthetic chemical fertilisers, pesticides and herbicides are depleting the soil's biomass.
In natural systems, animal waste, dead animals and plants are deposited on the ground and begin to decompose. This decomposing organic matter is broken down and dragged into the soil by small animals including earthworms. It helps feed bacteria and fungi that create structure in the soil and provide an ideal environment in which plants can prosper. The soil still emits greenhouse gasses as the biomass decomposes, but there is always a net gain in soil biomass.

The North American Prairies are a good example of how human activity has transformed a huge area of low rainfall grassland maintaining very large stores of biomass above and below ground into a biological desert. Large quantities of topsoil have been lost as the denatured soil succumbs to erosion, and life in the soil has been all but exterminated.
Deforestation world wide, where huge quantities of biomass have been lost above and below ground, occurs when humans clear land for modern (mechanical and chemical) agriculture, or as a result of wildfires. 

Large quantities of CO2 are added to the atmosphere in the smoke from these fires, and forest wildfires are a growing issue in Australia and other warm temperate regions around the world.

I have been an advocate for organic farming and practiced organic gardening for many years. I grow a surprising amount of organic vegetables, herbs and fruit in my small suburban garden using only homemade compost, compost tea and compost extract for fertility. I make about 3000 litres a year of high quality compost and use it all on my garden soil. I believe this, and my solar panels, go a long way towards offsetting my carbon emissions.

When degraded soil is normalised by regenerative farming in forestry, livestock husbandry, food cropping and horticulture, vast quantities of carbon are sequestered from the atmosphere, and bound up in the soil. The availability of sunlight is the main factor limiting photosynthesis and when the soil is completely covered by vegetation, the carbon cycle between soil and atmosphere will be back in balance.

These processes are remarkably efficient and would make a huge dent in CO2 concentrations in the atmosphere in just a few years if adopted worldwide. They would eliminate the need for synthetic fertilisers, pesticides and herbicides once the soil's natural protection was established.

There are many examples of farms and market gardens around the world practicing organic and regenerative agriculture, but there is a pressing need now for a paradigm shift in this direction worldwide without delay.