There has been much ado about Budget deficit issues from the Australia Federal Government. This is about nothing, compared to the increasing Carrying Capacity Deficit of the human species. William Catton in his book "Overshoot", (1980) used the following diagram for notions of sustainability. Its on page 252, and was describing the USA, but it applies globally. Read Catton's book for the original words and interpretation.

Panel A below is how politicians encourage us to believe where our drive for economic growth places us in the sustainable use of our biosphere. We are still assumed to be far away from our total carrying capacity, which is assumed to be stable. We are assumed to want to strive for more growth.  Australian politicians have recently touted nations in "Asia" to our North as still having a boom in development and consumption, with a growth in middle class lifestyles. Australia is assumed to benefit by supplying goods and services, and also growing in wealth and jobs.  The curve is a logistic curve, and assumes we are still growing at near an optimal rate of growth. Australian mainstream political parties carry on lyrically about growth as if there is no other possible future. The degree to which different growth ideologies blame each other for failures of growth can only mean their ideas have no grounding in reality.  They may also be just putting on a clown show for our benefit.

Panel B shows some awareness that we are using up non-renewable resources, and total carrying capacity has decreased, but we are still below the safety margin. A miracle is expected to happen, such that free markets with minimal wise regulation will stop the rate of destruction of carrying capacity. Economic growth is stopped, and technology becomes sustainable, and we sustain our current population and consumption, and manage to continue to use the maximum amount of sustainable extraction and maintain the impact of our population and consumption for ever more. Somehow the relatively fast transition to a "steady state" economy occurs without widespread economic depression or collapse.  

It may be possible to have a "steady-state" economy, if this follows the definition in having minimal draw-down on non-renewable resources, and sustainable yield on nature's renewable resources.  A switch to this will require considerable reorganisation of jobs, resource use, energy use and our financial system, and human behaviour and policies. This is quite a big change from our current economic organisation. William Catton writes that our species characteristic intransigence of institutions, behaviour and politics, means we cannot change appropriately and in time, to avoid overshoot. Our ignorance of carrying capacity destruction may be well disguised by economic markets, because of ecological system delays in feedback signals. We do not seem to pay attention to species declines and global warming indicators unless our economic profits are directly impaired.

"Overshoot will occur, if it hasn't already. We may come to feel guilty about stealing from the future, but we will continue to do it." That was written in 1980. Catton also wrote that overshoot had already occurred,  or was unstoppable, because of the momentum and trajectory of growth. A lot of people would agree today. In all of these panels, the present has moved another exponential doubling. At the time of writing, the global population was 4 billion. It is now past 7 billion, trying to reach 9 billion. Any realistic assessment today should place our ecological carrying capacity well below our load on nature, and show carrying capacity as declining. Catton then speculates as to if after the human crash, back to down something like 0.2 percent of present population, we will see some recovery and regrowth of human carrying capacity, followed by some delay of a new age of human "exuberence". Exuberence is an ecological description of a species that finds a new abundance of growth resources, and grows exponentially, as all species like to do. Because large amounts of the most accessible of Earths original endowment of concentrated mineral and energy resources will have already been scattered, any new age of growth will never be able to reach the heights of its previous exuberence.

Panel D shows the most likely future.  If mankind was forced to only live off the current income of present solar energy, through the biological food web, as a hunter-gatherer, or a horticulturist, or even as a highly technical and tool using species, using directly harvested solar energy, there is at best a low sustainable carrying capacity. This base-line capacity is only from nature's flow of energy and sustainable nutrient cycles.  Catton writes that "A major fraction of the recent, apparently high carrying capacity for human high-energy living must be attributed to temporary resources, that is non-renewable fossil acreage, the earth's savings deposits." This is declining rapidly, and so goes the support for our large population. Catton disparages the idea that nature wastes solar energy because photosynthesis is only 2% efficient, or that we can replace a large amount of it for ourselves. A large fraction of the energy of the sun drives the transpiration of water from the roots of the plant to out through the leaves, and helps drive the global hydrological cycle that resupplies us with fresh water. That is something we are not good at doing for ourselves.

After our age of exuberence, the recoverable sustainable carrying capacity of the earth for humans may be negated for a long, but temporary period of time, with detrimental changes to climate and species diversity wrought by our changes to the global habitat that we once dominated.  The earth's ecosystems will never be again like the one that nourished our civilizations. As a result, we will never again become a dominant species on this planet after our fantastic rise and decline. And that would be be a very good thing.

Our current carrying capacity deficit includes of all additional energy we get from our declining supply of fossil fuels, and the minerals we mine using them, and the boost to agricultural output they enable.  Our deficit includes the takeover and splintering of ecosystems. It includes the pumping of water from depleting underground aquifers. It includes the dam systems of irrigation, and the takeover and building over of soils.  Catton described these as 'virtual ghost acreages'.

Our carrying capacity deficit includes our systems of trade, by which local regions increase their temporary carrying capacity beyond local limits, by importing or exporting resources. Trade allows each local region to evade Liebig's law, which is that local system outputs are limited by amount of least available resource. This creates a global conglomerate carrying capacity beyond the arithmetic sum of regional carrying capacities without trade. The speed and scale of global trade is dependent on use of temporary fossil energy resources, for fuel and infrastructure. Attempts to overcome declining local carrying capacity by increased trade, worsen the long term global carrying capacity deficit, by increasing the total rate of non-renewable resource draw-down.

Our combined ecological deficits of global warming from our carbon dioxide waste build up, and our growing carrying capacity deficit, both temporary and long-term, ensure that their combined effects are likely to bring about a rapid and ruinous collapse in the next few decades, for which we are a thousand times unprepared. The reasons for our current success and dominance make up our biggest deficit.

Ecologic overshoot for all of us is temporary Economic growth that increases our population load way beyond the long term global carrying capacity. This is carrying capacity deficit as applied globally. Overshoot applies even more so to each local and regional situation, because of the incremental overshoot which has been enabled by global trade. As energy dependent supplies, manufacturing and food surpluses, and virtual water that are available for trading become diminished, each local region will experience more of the full extent of its overshoot. The previous sacrifice of local water supplies, good soil, and forests for the sake of roads, building and mining, for the pleasure of foreign corporations and their acolytes, big finance and empire building, will ensure a more rapid and deeper collapse of this global civilization.  In many places 'development' will have burnt many of our bridges that might have taken us back to relying on local ecosystems of nature.

William Catton points out that in this behaviour we exhibit no more wisdom than the exuberant overgrowth of Algae in the northern european pond in the warming spring time, as the last years load of dead leaves provides a resource feast.  After a few weeks of rapid growth, the pond is filled with auto-toxic byproducts, and the food has gone, so a massive die-off follows. The term for a creature that primarily feeds of dead organic matter is called a "detritivore". That is what we have become, as global civilization has grown to a collossal size based on extracting energy and chemicals from large quantities of dead organic matter, the gift of fossil fuels.  There are about ten times more used fossil fuel calories that provide our food than the calories in the food itself. Now our global pond is filled with climate-toxic and ocean-toxic by-products, and the easily available supply rate is falling. A massive die-off will follow. It is a simple and common ecological sequence, just not normally involving an entire planet.