During 4 years after graduating from university I worked with one of my professors on a model simulating migration movements within the country. What I remember most are the times that I rushed into his office because I found an unexpected result in my analyses of the data. My prof would always say: 'that makes no sense, you have to go back over your work because somewhere, somehow you missed something'. He was always right. That taught me an important lesson: if a finding or a theory does not pass the smell test you don't have all the right components.
In the past decades we have received a lot of information on man made climate change due to increasing
CO2 levels. I can see the climate becoming more erratic, more extreme, so I know by my own observation and the observations of many others that something is happening. But I miss something quite essential when we point only to CO2, because humans in the past century (and before but in a less destructive way) have totally altered our landscape as well. That is bound to have effects too! And when we understand those effects it will help us find additional answers on what to do to at least try to mitigate climate change.
I give this book 10 out of 10 acorns because it offers us an extensive further explanation on how one of the major climate balancing system, the rain cycles, also got out of whack. Unfortunately the book gets hardly any attention. I hope at Permies we can shine a light on it. It's available for free download so everybody can read it.
The authors build their case on the man made changes to our worldwide landscape through growing cities, extensive monoculture on otherwise bare soils, deforestation, excessive drainage applied everywhere, and how that interacts with the two water cycles they identify: the small and the large water cycle. They connect the cycling of water to
solar radiation and how it has a different effect on forested and vegetated areas, opposed to areas with less vegetation, or even bare
concrete surfaces. A lack of evaporation means less cooling or even heating of the atmosphere. They list a lot of cascading effects and findings, I will only mention the main ones.
The large water cycle brings water from the oceans to the land. That mostly happens in bigger and more violent storms. The small water cycle then recycles part of the water that fell in these big storms into lighter more frequent rain. They argue that because we drain the land, through deforestation, through bare landscapes used in agriculture, through hard surfaces in growing cities, etc we are diminishing the small water cycle. This in turn leads to less rain and when it finally rains it's the big storms from the large water cycle.
They go on explaining how the sun warms the earth and how vegetation and water in the soils cool the climate. Loosing this cooling effect, on bare land and in cities, creates islands of heat which further drive away the small water cycle rains from these areas. Instead of the rain falling spread more evenly it now concentrates more, falling mainly in the cooler mountains. This in turn leads to more flashfloods when the rain comes rushing down the watersheds They don't stop there. Draining the landscape over longer periods of time leads to a small net loss of water on the land, which then flows through rivers to the sea adding to the rise in sea water level.
The authors call for a new water paradigm, to give water it's role back in our landscape. It's something we already know in
permaculture, but still it's good to get it confirmed from a different source with a different viewpoint. Let's get this book the attention it deserves! I think they state their case very well and
permaculture sure helps in restoring the water cycles back to their needed influence on our climate.