Most of the headlines in the news are rightfully taken by the threat of global warming, but there is an ongoing ecological disaster that will affect food production, a degradation of the topsoil, and we are not talking about it enough.
A recent United Nations study showed that in the past 40 years one-third (1/3) of the Earth's land has severely degraded, and fertile soil is being lost at the rate of 24 billion tonnes a year, due to agriculture.
At the same time, this is a call for a shift away from destructively intensive agriculture.
As we are risking plant-wide famines and starvation, the question is how to fix this, how to stop soil from degrading, and how to increase fertile top soil.
The first thing that comes to mind is people. There are simply too many of us, and, for any issue we are facing, that number will need to reduce in the future. Sooner or later, if we plan to survive, we will need to find ways to manage human numbers and diversity.
Currently, there are 7.5 billion of people, and we shit a lot—literally.
How much do we poop each day?
Approximately, for each 12 pounds of body weight, humans produce around 1 ounce of faeces. Therefore, a person weighing 160 pounds (72kg) produces an average of just under a pound (0.45kg) of poop each day.
As there are 7.5 billion people, and they poop 1 pound each day a year (365), the total amount of poop a year is 2,737,500,000,000 pounds or 1.24 billion metric tonnes.
When human faeces are collected and used as manure, frequently-used terms are “fecal sludge" or “night soil”. Human poop contains mostly water, and it is rich with plant nutrients. Urine contains urea nitrate that can be used in agriculture.
Although in areas where the soil has poor quality the local population may decide to use night soil as fertilizer to grow food, there is one issue. Unprocessed human faeces as fertilizer can be dangerous, as it may contain disease-causing pathogens.
These risks are reduced by composting, which can produce methane (CH4) for later use in heating, cooking, electricity production, and even as car fuel. However, there are concerns about usage of sewage sludge compost as fertiliser for vegetable gardens and crop land, because of the dangerous levels of heavy metals usually found in sewage sludge.
Because of the sheer amount and usage potential, this is definitely something that should be explored more. Potentially, with bio innovations, it would be possible to use it for our and nature’s benefit.
Just the combined manure of the two animal species, we use in farming gives us ~18 billion tonnes of soil that, if used property, could potentially replace the land we are using.
As we live in a closed system, it is obvious that land along with all essential nutrients for plants cannot be really lost. Therefore, our biggest issue is that soil isn't recycled in a proper way. All animal and food waste could be used for the compost and methane production (CH4 is a fuel and greenhouse gas), later for replenishing the top soil. Even then, we would need to be careful about human population growth, our own food needs and frequent exploitation of soil without rest it, jeopardising stability of the soil's microbiome.
In addition, vertical farming, lab-grown meat and usage of aquaponics could reduce the amount of land, water and energy we use in food production, but they would not solve essential mineral production and retrieval from the waste.
At the end, only way to continue is to plan our habitats having in mind circular economy and way of living in every way we can.