August 2nd, 2017 marked the time taken this year to consume an entire year of nature's regeneration capacity, so in total, human civilization is consuming 1.7 earths in a full year. How can that be?   Nature's capital and regeneration capacity depends entirely on in-coming solar energy.  We are consuming both, and are at maximum rates of fossil fuel consumption as well. Natures regenerative ecosystems and species have been replaced by agriculture, over-hunting, cities, mines, factories, dwellings, lots of concrete, and cut into pieces by transport infrastructure. The fossil fuel economy has almost consumed everything, and now it must end.

Here is the bathtub, a metaphor for earth. The only inlet is the flow of Solar Energy. The only outlet is the flow of heat energy into space. The average temperature, or bath tub level, is stable when the energy in and out flows are equal. The bathtub also includes the stored sunlight, in the form of fossil fuels.

There is also another flow, related to energy, which is the states of distribution of all the elements of matter, liquids and gases in the planet. They can practically never leave the planet, due to gravity, but their relationships change with flows of energy. With the release of fossil fuel energy, it is generally for the worst, despite benefits of temporary order we create for ourselves, a greater pile of waste is accumulated, which also practically can never leave the planet, or be simply restored to its initial state.

'Entropy' relates to "temperature", and energy concentration and flows, and also to the distribution of every kind of matter, and their chemical arrangements. This comes under the general term of "entropy", and entropy of matter alters with changes that take or produce energy. Entropy as a relative quantity can be low or high. Low values are improbable, associated with dense concentrations of pure materials like ores. High values of entropy are associated with materials that diffuse, spread out, where energy has been released. It takes energy to produce low entropy forms of any material. All system changes, and the passage of time itself, are related to how entropy of a total system must always increase.

Cassandra's legacy site has a detailed reflection on Entropy, and ends with the stoic - like quote, “You cannot win against entropy, but you must behave as if you could.”  Western Industrial human civilization pretends it can win! This is done by ignoring all of the costs, including the accumulation of waste, and the decreasing resource base, and the decline of nature.

The direction of entropy change is confusing, because "high" and "low" are gravitational metaphors. Entropy is a confusing metaphor for disorder. When water flows downhill, it does so because the entropy law, the second law of thermodynamics, says it must. The total system always increases, as "work" is done on the surroundings of the flow. Videos of flooding waters from extreme weather or tsunamis show its capacity to push stuff around. Hydro-electricity transfers some of the kinetic energy of dam water release. The water at the top has lower entropy, than the water at the bottom. Entropy goes in the opposite direction to flow, so its very metaphorical, and also very real.

The bathtub metaphor was mentioned in this article on Earth Overshoot Day, which is coming earlier every year.

If every country in the world lived like Australia, Earth Overshoot Day would have been on March 12. Australia is top of the earth bathtub draining league table, now outranking the USA. The USA may start to lead the decline rates.

This year Earth Overshoot has just past, or yesterday from writing this, August 2nd. Once upon a time, there was a safety margin, and the human species consumed for a full year, and didn't go beyond natures reserve regeneration capacity. Our year is appropriately seasonal, as we harvest and regrow our agricultural outputs to feed ourselves, we have appropriated nature's own capacity for regenerating itself. By 1971, we started draining the bathtub more each year, more than it could recover.

And so much of this consumption goes to waste.

Dr McBain told the ABC there were many interweaving factors at play.

In her research, which compared future ecological footprints with research about planetary boundaries, they found that our global cropping footprint is likely to exceed the planetary boundary for land clearing between 2025 and 2035.

A full systems break-down is coming up soon, as the economy must falter, as the low entropy potentials are drained. What happens when nature fails to regenerate at all? As well as aiming for a complete over-shoot of nature, we are already warming the globe at something like 170 times faster than the base-line rate for the Holocene. The only potential brakes appear to be the expected failure of global oil supply for our industrial engines, with about only half our current supply available by 2030. This is a real "Collision Course". Brace for impact. Australia's rate of earth consumption will slow rapidly.

Meanwhile, the great immigration barriers are going up, and governments are failing, already succumbing to the "Age of Consequences", soon to visit your neighborhood. Part of our problem, as stated in Herman Daly's review of Collision Course, is that "we have a tendency to forget, that reason and honesty must confront power and corruption, not just honest error".

Even correcting the honest error requires a substantial paradigm shift–a change from the pre-analytic vision of the economy as the whole with nature as a part, to the recognition that the economy is the part. The economy is an open subsystem of the enveloping ecosphere that is finite, non-growing, materially closed, and entropic.