Let’s not beat around the bush: this essay on excrement is fascinating, because it constitutes an agricultural, urban and ecological issue. The subject is smoking hot: what to do with all this shit ? And this leads to a scientific and democratic debate.
“ Can we admit, freely and openly, that the way we eat and the way we deal with our shit are essential acts of citizenship as important as the way we vote? ? I think, in all cases, the answer is yes. »
It is undoubtedly because they knew that I shared this postulate that The life of ideas distinguished me for the review of a book whose title constitutes in itself a program: Merde. And this is not a rhetorical formula, since the author can affirm: addressing health problems “ took us from the manure pile by the barn to a new way of doing science, through associated social-ecological systems. The time has come, I think, to consider solutions “.
The question of shit indeed conceals, like a mise en abyme, a whole series of technical, social and intellectual challenges which, once the first post-scatological malaise has passed, should hook a curious and willing reader. Because the problem with shit lies precisely in our apprehension to think about it and manage it well.
You are flow
A simple little calculation. At a rate of 600 to 800 grams of food per day, to which water must be added – food and water which, unless body mass increases, will be expelled in one way or another – the human body is passed through by a material flow of more than half a ton per year. And, if you give yourself a reasonable life expectancy of 70 years, that represents a little over forty tonnes for a lifetime, or, if your weight is 65 kg, approximately 630 times your body weight.
In other words, your body will ultimately only represent a 630e about the material reality of your life: before being stock, you are flow. Managing your life is above all managing these flows. If you now extend this reasoning to all humans and animals, the annual total rises to 400 million tons for humans and more than 14 billion tons for other animals. But these quantities continue to increase, while some economists say that more people are needed to keep the economy afloat. Brief, “ we are not in shit “.
The overwhelming majority of animal manure comes from our farms. The author estimates that in 2010 the quantity produced by all the world’s livestock (sheep, goats, pigs and chickens) is close to 14 billion tonnes, which represents 35,341,235,000 million cubic meters. An amount very close to the evaluation of the total excrement of terrestrial animals (earthworm excluded). This is not surprising, as farm animals represent more than 95 % of terrestrial vertebrates. Their shit is ours.
The reader will have understood, the masses at stake are truly astonishing, and we need to “ talk poop » with lucidity.
Ambivalence of shit
Shit is wealth and threat.
Wealth, because it is part of natural cycles. It is what animals return to the plant world, in particular through organisms (insects, fungi) that are coprophagous, that is to say, those which have the good taste to feed on our excrement and thus, to make them even more accessible to plants. These droppings are rich in nutrients. In certain forms and in reasonable quantities, they powerfully stimulate soil and plant life. We used to talk about manure like brown gold and the term fertilizer (which enriches the soil) says what it means.
But while poop is a blessing for coprophagi and plants, it is a threat to the organisms that produce it. It is a vector of parasites and diseases, the most famous of which is undoubtedly cholera. Beautiful lesson from nature, which forbids us from being self-sufficient by eating our own shit, despite its nutritional richness, but which obliges us, to prosper, to enter into a sort of natural contract which binds us to other organisms in a system of interdependence.
Draining shit is not treating it
In England, we had to wait for the XIXe century and John Snow so that the link between water pollution and epidemics is recognized. Under the Second Empire, Eugène Belgrand had the sewers of Paris built. That said, Rome had already organized urban sanitation, with the cloaca maxima (large sewer).
Good urban sanitation measures are evacuating the shit, if you then have a place to throw it away. But this only shifts the problem to the location of the evacuation itself, which, with current urban growth, is becoming a colossal problem. What to do with all this shit ?
“ The Chinese, who had one of the most intensive and, until recently, sustainable agricultural systems, have been collecting and trading human feces for 3,000 or 4,000 years. Researchers estimate that 90 % of all human waste produced in China throughout history has been recycled and provided around a third of all the fertilizer used in this country. »
But what is true for civilizations that are still overwhelmingly rural and quasi-vegetarian is more difficult for urban societies with a meat diet. We could live with this amount of manure if, at least, it was used to regenerate depleted soils. But the manure piles up, concentrates, accumulates in a few places, which suffer rather than benefit from the presence of stools, despite all their nutrients and bacteria. It is also hyper-urbanization, a political and economic issue, such as eating habits and the consumption of meat products – and, behind this, the agricultural model – which must therefore be addressed.
Certainly, the author concedes some techniques such as methanization, but he warns the reader against any excess of techno-optimism. “ In technology as in science, those who claim radical innovation are often liars. (…) At the heart of the wicked problem of shit, food and ecological sustainability is a theoretical challenge. » We can develop solutions ad hocaccording to a linear vision of nature. These theories may work in factories or laboratories, but they are disastrous in the outside world. So, can we save » science ?
The shitty question
The answer is yes, if we take a broader view of science, as a means of generating knowledge grounded in the real world. Considering the different facets of the shitty question, linking behaviors, cultures, techniques, representations of the world, it is vain to hope that large technical installations will provide the solution. Citizen participation is an essential element, particularly to understand the cultural foundations of the relationship with shit and find acceptable solutions for its decentralized management (separation of stools and urine, dry toilets, local composting, etc.). In short, to emerge from the pile of manure.
Likewise, public involvement in the detection of problems and sources of risk is essential, as our knowledge is fragile, decisions are urgent and the stakes are high. Since it is not just a matter of evacuating it to large wastewater treatment plants, intelligently managing shit becomes a widespread and common matter, and no longer just the business of a body of specialized engineers, of companies and experts. The author, David Waltner-Toews, takes up the reflections of Silvio Funtowicz and Jerry Ravetz, philosophers of science, who speak of science “ post-normal »: it is not a question of overturning current paradigms – science progressing from revolution to revolution – but of adapting to a series of paradigms. In this case, there is not just one point of view on shit, but several, that of the doctor, the anthropologist, the gardener, the ecologist, the mayor, the technician and each of them. us, which must be well articulated to achieve sustainable management.
The problem of shit, democratic question, factor of science, catalyst of an epistemological revolution: who would have believed it ? The tricks of reason are definitely impenetrable.
This work therefore reinforces those who think that the ecological challenge calls for a profound change in our ways of thinking and being. If the sequence of the first chapters gives the feeling of an impressionist approach, juxtaposing information and anecdotes, this defect is made up for in the second part of the work, where the author’s reasoning unfolds pleasantly. A useful book to leave, therefore, in this small room where most of us, forced to sit, take the time to read a little…