Savory’s Brittle and Non Brittle Climate Classification

Written by Doug Crouch


In the recent years of Permaculture, about the last ten (2008-2017), there has been a fusion of Permaculture and Holistic Management (HM).  This brought in the terms regenerative agriculture, Carbon Farming, and many more terms like Darren Doherty’s Regrarians movement.  They all stem from the same desire to enhance the ecosystem’s inherent quality and the agroecology interaction.  HM has a bigger focus on decision-making while permaculture more on design so the two actually fit together well. Unfortunately it is rumored that Mollison wasn’t a big fan of Savory, but alas, now the fusion has happened and Mollison’s climate classification is strengthened by Savory’s Brittleness of Climate Scale.

Brittleness Pattern

The brittleness scale goes beyond just temperature and rainfall, which are the two climate classifications that Bill presented.  It does center around rainfall but Mollison looked at total rainfall and temperature ranges while the brittleness scale looks at precipitation distribution and totals with its correlation to the presence of humidity as well as temperatures.  It is amazing that as we zoom around the world the same pattern that J. Russel Smith presented of forest, field, plow, desert resulted in varying results.  In many places in the world it did indeed result in a desert whilst in others a green condition persists despite “the burning and the looting” as to quote Bob Marley.  This is what typifies the brittleness scale, this varying result of ecosystem degradation. HM uses a 1-10 scale to describe brittle and non brittle climates but I will steer away from that for your further research.

Brittleness is defined by wiki as the following:

A material is brittle if, when subjected to stress, it breaks without significant plastic deformation. Brittle materials absorb relatively little energy prior to fracture, even those of high strength.

Thus our ecosystems are under significant stress these days and even though the above description is in reference to materials, it can easily be applied across disciplines.  So when ecosystems are brittle, they can absorb less and less energy prior to their failure even though structurally it might even appear very sound.  For example in some ecosystems in the world, a forest may stand looking very strong and if you present stress (deforestation, burning, ploughing, use of chemicals, over or under grazing, pollution, etc.), the ecosystem declines quickly and rebounds very slowly.  However in other climates the same stress is presented and they rebound quickly (succession).  This is brittleness and is tied again to the distribution of rainfall and its total amount and relationship to humidity. It involves also temperatures and the time and space relationship of a given ecosystem and larger climatic factors. Thus below we will use rainfall/temperature distribution charts throughout the months of the year to display this. Also certain land forms and other climatic factors will create more humid conditions including proximity to the sea, fog, temperature variations, valley and ridge conditions, soils higher in organic matter percentage, and also wind patterns. When you put all these together the mosaic of climate becomes clearer. In essence you can have a much more brittle landscape than another despite having a higher yearly rainfall. The Koppen Geiger map system helps with understanding climate analog, but I find regions that I have traveled to in other parts of the world to be labeled similar to others and yet they are different climates and ecosystems.

For example, despite not being classified in Mollison’s drylands section because of rainfall totals, a place like Villa Martin, Southern Spain, Andalusia province, is a fairly brittle climate.  It receives in the area around 600 mm of rainfall a year putting it above the typical drylands context that Bill Mollison presented of under 500 mm.  However drylands crops thrive well there and to look at this framework of reference, the brittleness scale, creates a better climate context when looking at the whole picture.  Thus we can see that we should be using drylands techniques despite not being in Bill’s drylands climate context. Its also very obvious when you observe the landscape and the crops like olives that grow well there. Moreover, knowing the brittleness scale will allow you to adjust certain techniques but does also serve as part of the climate analogue.  The two are put together essentially for the best picture. So in the end we can see that places with varying temperature regimes, precipitation regimes (rainfall and its distribution), and humidity regimes, paints a more holistic context.


Thus where I come from in the Midwest of the United States of America (See top left graph), an enormous food-producing region, is a non brittle climate.  It has been deforested, ploughed, industrialized, grazed poorly, cropped, over and over again and still, the environment grows crops well with little or no irrigation and more importantly in this context the forest responds very quickly.  If you don’t cut the grass you will see woody perennials, invasives and native pioneers, appear within two years and sometimes within months.  The precipitation distribution is very regular with an almost constant throughout the year.  There are small peaks and valleys but in the grand scheme of other climates that we will look at below it is very steady and totals quite high (0ver 1000 mm).  Food grows really well here but so do diseases, pests, molds, and so on. That is in part because the dry time of the year, in terms of humidity, is in the dormant season yet there is precipitation (snow, ice, and rain).  In the growing season the air is very humid despite the high temperatures making it really feel like you are in the tropical jungle.  Summer rain is a gift from the gods it seems thus making plants literally grow overnight by cm’s or inches. Furthermore, In Europe you have similar forests and food crops being grown commercially in the Central and Eastern regions, which are also humid zones overall.  Soils and temperatures and humidity differ thus so do crops but they are both non brittle climates. Also there are subtropical and tropical climates such as Buenos Aires, Argentina and Singapore, Singapore, that have a more even distribution of rainfall and humidity persisting longer making them non brittle landscapes.

Mediterranean regions are fairly brittle climates but within these regions both in Europe, North Africa, and the Middle East you will have differences.  There are of course other places in the world where these fairly brittle climates exist like parts of New Zealand, California, and Australia.  These climates are classified as having hot dry summers and cold wet winters.  The temperature and average rainfall and its distribution will differ in areas usually based on altititude and the maritime influence of proximity to the ocean.  You will have certain microclimates (actually topoclimates) that lessen or strengthen the brittleness.  Sintra, Portugal, Grazelama, Spain, and parts of Mt. Etna Sicily all have pockets of more humid zones making them less brittle. Rain shadows from mountains or winds moving up from the Sahara can also be the reverse.

The key with these climates is they typically go four to seven months with virtually no precipitation in the warmer time of the year.  Some areas it can be eight months and with the erratic weather patterns its tough to say year after year.  And as we break the fabric of the landscape with the stresses of modern times mentioned above, the ecosystem breaks much more easily because there is a lessening of the driving force of nature as Da Vinci put it; water. So when temps are low, humidity is high when the rains are present in the winter making it a quite unpleasant winter besides those balmy sunny days.  As the temperatures switch, along with winds most often, humidity drops rapidly and plant growth comes to a grinding halt without irrigation.   Furthermore, a permaculture project I stayed at in Cordoba Province, Argentina was a brittle climate despite the summer rainfall and higher humidity in the warmer part of the year.  It just had no winter precipitation so it was in that sense the opposite of a Mediterranean climate but essentially the same graph because of being in the Southern Hemisphere.  The lack of winter humidity, but the ecosystem not going dormant, made it also very possible to easily break this climate. It also got less than 500 mm of rain making it a dry area in general.

There are other places in the world that receive high monsoon rainfall amounts that would never be considered a drylands climate under Bill’s climate classification but are very brittle indeed. They receive huge amounts of rainfall in short periods and often go long periods without much precipitation and high heat.  In certain places this drops the ambient humidity very low and makes the climates very brittle.  Also there are of course places in the world that receive so little rainfall in the year, regardless of its distribution, that it is simply not a humid place and makes it a brittle climate.

Overall we need to know this as to know which strategies and techniques to follow. Rest of pastures is something that regenerates the grasslands or Savannah landscapes in non brittle climates yet in brittle climates they simply don’t.  This has been a big fundamental finding from the HM movement as we have failed to adopt certain practices that are tied to non brittle climates in brittle climates.  In these brittle climates we have to intervene in ways we might not have to in non brittle climates. Allan Savory is still pushing this message and I applaud his efforts, which is part of the reason I have invited this section into the climate part of this handbook and teach it in the PDC.  It simply adds a greater depth of climate analysis and adds to our chances of success in ecosystem regeneration.  And with ecosystem regeneration, we often have social regeneration. Brittle climates have been flash point of war and strife for many ages because humans and their animal instincts often squabble over natural resources.  If it is not in the ground as minerals, oils or gases, it often leads to conflict. Those also help in the modern day but as they put it in the latest Mad Max movie, seeds and water are things to cherish deeply.  Thus the more we know about climate the better off we will be towards implementing the ethical basis of permaculture in our projects.

Syrian Desert in the Middle East, courtesy of

Written by Doug Crouch

Header Art by Anita Tirone