The more we know about climate the better off we will be towards implementing the ethical basis of permaculture in our projects. Thats how i finish this latest TreeYo EDU article back in Chapter 5, Climate. Savory's Brittleness scale is a great context builder for your sites and is an important design assessment tool. Is your site Brittle or Non Brittle, does your ecosystem easily break when presented stress or rebound quickly when the same stresses of modernity are presented? Read more at the link below!
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.
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.