A simple model of the earths climate to show how greenhouse gases and aerosols in the atmosphere affect the temperature of the earths surface and the atmosphere​.

Small community that becomes overpopulated requires change in order to survive

This model simulates the growth of carp in an aquaculture pond, both with respect to production and environmental effects.

Both the anabolism and fasting catabolism functions contain elements of allometry, through the m and n exponents that reduce the ration per unit body weight as the animal grows bigger.

The 'S' term provides a growth adjustment with respect to the number of fish, so implicitly adds competition (for food, oxygen, space, etc).

 Carp are mainly cultivated in Asia and Europe, and contribute to the world food supply.

Aquaculture currently produces sixty million tonnes of fish and shellfish every year. In 2011, aquaculture production overtook wild fisheries for human consumption.

This paradigm shift last occurred in the Neolithic period, ten thousand years ago, when agriculture displaced hunter-gatherers as a source of human food.

Aquaculture is here to stay, and wild fish capture (fishing) will never again exceed cultivation.

Recreational fishing will remain a human activity, just as hunting still is, after ten thousand years - but it won't be a major source of food from the seas.

The best way to preserve wild fish is not to fish them.

This model simulates the growth of carp in an aquaculture pond, both with respect to production and environmental effects.

Both the anabolism and fasting catabolism functions contain elements of allometry, through the m and n exponents that reduce the ration per unit body weight as the animal grows bigger.

The 'S' term provides a growth adjustment with respect to the number of fish, so implicitly adds competition (for food, oxygen, space, etc).

 Carp are mainly cultivated in Asia and Europe, and contribute to the world food supply.

Aquaculture currently produces sixty million tonnes of fish and shellfish every year. In May 2013, aquaculture production overtook wild fisheries for human consumption.

This paradigm shift last occurred in the Neolithic period, ten thousand years ago, when agriculture displaced hunter-gatherers as a source of human food.

Aquaculture is here to stay, and wild fish capture (fishing) will never again exceed cultivation.

Recreational fishing will remain a human activity, just as hunting still is, after ten thousand years - but it won't be a major source of food from the seas.

The best way to preserve wild fish is not to fish them.

This model simulates the growth of carp in an aquaculture pond, both with respect to production and environmental effects.

Both the anabolism and fasting catabolism functions contain elements of allometry, through the m and n exponents that reduce the ration per unit body weight as the animal grows bigger.

The 'S' term provides a growth adjustment with respect to the number of fish, so implicitly adds competition (for food, oxygen, space, etc).

 Carp are mainly cultivated in Asia and Europe, and contribute to the world food supply.

Aquaculture currently produces sixty million tonnes of fish and shellfish every year. In May 2013, aquaculture production overtook wild fisheries for human consumption.

This paradigm shift last occurred in the Neolithic period, ten thousand years ago, when agriculture displaced hunter-gatherers as a source of human food.

Aquaculture is here to stay, and wild fish capture (fishing) will never again exceed cultivation.

Recreational fishing will remain a human activity, just as hunting still is, after ten thousand years - but it won't be a major source of food from the seas.

The best way to preserve wild fish is not to fish them.

HANDY Model of Societal Collapse from Ecological Economics Paper 

This model simulates the growth of carp in an aquaculture pond, both with respect to production and environmental effects.

Both the anabolism and fasting catabolism functions contain elements of allometry, through the m and n exponents that reduce the ration per unit body weight as the animal grows bigger.

The 'S' term provides a growth adjustment with respect to the number of fish, so implicitly adds competition (for food, oxygen, space, etc).

 Carp are mainly cultivated in Asia and Europe, and contribute to the world food supply.

Aquaculture currently produces sixty million tonnes of fish and shellfish every year. In 2011, aquaculture production overtook wild fisheries for human consumption.

This paradigm shift last occurred in the Neolithic period, ten thousand years ago, when agriculture displaced hunter-gatherers as a source of human food.

Aquaculture is here to stay, and wild fish capture (fishing) will never again exceed cultivation.

Recreational fishing will remain a human activity, just as hunting still is, after ten thousand years - but it won't be a major source of food from the seas.

The best way to preserve wild fish is not to fish them.

HANDY Model of Societal Collapse from Ecological Economics Paper 

Plant-Based Farm-to-Fork Food Systems Model

Simple Health Care Supply and Demand Interactions

This simple model will attempt to demonstrate how modern civilization's groundwater practices are unsustainable and how they are affected by the changing climate.

This simple model will attempt to demonstrate how modern civilization's groundwater practices are unsustainable and how they are affected by the changing climate.

Template for mapping SDG linkages for sustainable systems engineering

Simple Health Care Supply and Demand Interactions

This model incorporates several options in examining fisheries dynamics and fisheries employment. The two most important aspects are the choice between I)managing based on setting fixed quota versus setting fixed effort , and ii) using the 'scientific advice' for quota setting  versus allowing 'political influence' on quota setting (the assumption here is that you have good estimates of recruitment and stock assessments that form the basis of 'scientific advice' and then 'political influnce' that desires increased quota beyond the scientific advice).

HANDY Model of Societal Collapse from Ecological Economics Paper 

This model incorporates several options in examining fisheries dynamics and fisheries employment. The two most important aspects are the choice between I)managing based on setting fixed quota versus setting fixed effort , and ii) using the 'scientific advice' for quota setting  versus allowing 'political influence' on quota setting (the assumption here is that you have good estimates of recruitment and stock assessments that form the basis of 'scientific advice' and then 'political influnce' that desires increased quota beyond the scientific advice).

There is a general belief that wind and solar will enable us to get fossil-fuels-use to net-zero. This is, unfortunately, impossible as an examination of only some limitations and constraints associated with solar and wind energy will show. Solar panels and wind turbines have now been used for many years, but until now they represent only a tiny fraction of total energy use (not just electricity but all forms of energy).  In 2020, wind accounted for 3% of the world’s total energy consumption and solar amounted to 1% of total energy. Thus, the combination of wind and solar produced only 4% of world energy in 2020. How long will we have to wait before they can generate enough energy to power the world? The climate emergency will not wait.  Solar panels and wind turbines have average lifespans of around 15 to 30 years, then they need to be replaced. However, the manufacture of the replacements will require fossil fuels since one cannot use wind or solar to build wind and solar. Further, solar panels do not supply enough energy. The net-energy gained from solar panels is only about 3.9:1. This net-energy ratio is known as ‘energy return on energy invested’ (EROI) and is critically important.  Unfortunately, the EROI of solar is far too low to power a modern industrial society, which requires an EROI of about 12:1. There is also the question of space. Renewable energy sources can take up 1000 times more space than fossil fuel – that is bad news for agriculture and food production in a world that is already experiencing food shortages because of global warming. If you take these limitations into consideration, then it becomes clear that solar and wind cannot solve our energy problem – they are a fix that will inevitably fail. 

This model incorporates several options in examining fisheries dynamics and fisheries employment. The two most important aspects are the choice between I)managing based on setting fixed quota versus setting fixed effort , and ii) using the 'scientific advice' for quota setting  versus allowing 'political influence' on quota setting (the assumption here is that you have good estimates of recruitment and stock assessments that form the basis of 'scientific advice' and then 'political influnce' that desires increased quota beyond the scientific advice).

Various factors affecting South East Queensland's koala population.