Soil, Plants and Thunderstorms

This spring, Makery co-produced issue 6 of the occasional newspaper The Laboratory Planet. This issue imagines a peasant and neo-peasant future, invented by global peasants, organised in diverse territories, cultivating biotopes that are more heterogeneous, more democratic and therefore more habitable. Julian Chollet discusses here how climate, clouds and ecosystems are closely linked.

Soil is not only the foundation of life for all land-based organisms, it has an astounding influence on the climate. The general narrative on climate change is slowly transitioning from an almost exclusive focus on greenhouse gasses, to a more holistic perspective that includes the active role of ecosystems. Millán M. Millán’s in-depth research into changes in land use on water cycles in the western Mediterranean encourages us to not only transform agricultural practices, but to regenerate landscapes and reimagine society.

Today, most of the Iberian Peninsula is severely threatened by desertification, and especially its southern regions are extremely dry. But it has not always been like that. The eastern coastal lowlands were once characterized by swamps, the hills and mountain ridges by open forest. Let’s look at the formation of summer storms in such a landscape: with a gentle morning breeze, moist air sweeps in from the sea, rises on the slopes of the mountains and forms dark clouds that eventually give birth to a thunderstorm. Yet, this meteorological ballet is not solely orchestrated by physics and geology – biology also plays a pivotal role. “Soil is the womb and the vegetation the midwife,” Millán Millán said about his decades-long research on these water cycles. The generation of rain clouds depends on the vitality of the land. First of all, additional water is needed. It is pumped up from the soil by the plants and evaporates on the surface of their leaves. A single tree can charge the clouds with several hundred liters of water per day. The other ingredients for a proper thunderstorm are ‘seed crystals’: tiny organic particles such as pollen, fungal spores and bacteria that allow water vapor to form droplets or ice crystals. Energetically speaking, it’s an open system – heat can escape into higher strata of the atmosphere – but when it comes to the water, it is cyclical, meaning that most of it returns to the soil and sea.

Although the Romans had already started draining swamps and cutting trees, the land stayed green and lush until the advent of large-scale “development” in the 20th century. Nowadays, the shorelines of Spain are crowded with cities, towns and beach resorts, while further inland, the native woodland and most of the traditional farming systems have been replaced by industrial agriculture. As a direct consequence of this shift in land use, thunderstorms have become rare. When they occur, the sudden deluge poses a significant challenge. Because sparse vegetation is unable to absorb sufficient water and already degraded soil is vulnerable to erosion, the impacts are profound. This “second leg of human-induced climate change”, as Millán calls it, should not be underestimated. Changes in land use lead to major disruptions of local weather patterns, but they also exaggerate climate anomalies elsewhere. While the Iberian Peninsula dries out, the water vapor travels far into the continent and can eventually induce floods in central Europe. Lack of sweet-water influx furthermore increases ocean salinity and affects the so-called “Atlantic- Mediterranean salinity valve” at the Strait of Gibraltar, which in turn can change the formation of low-pressure systems and storms on a much larger scale.

The western Mediterranean water cycle is a great example of the interconnectedness of soil, ecosystems and climate. Similar dynamics unfold across the globe, from central Chile to California and western Australia. All these regions are severely affected by land degradation – catalyzed by urbanization and industrial agriculture – which leads to a downward spiral of erosion, desertification and extreme weather events. Millán’s research shows how the current focus on greenhouse gasses limits our understanding of climate change. Even if we could stop all emissions today and restore the atmosphere to pre-industrial CO2 levels, this would not revive previous water cycles and climate systems. It’s not enough to transition to ‘green’ energy and organic agriculture. What we really need is to regenerate landscapes on a large-scale. Then as a side effect, these ecosystems would absorb CO2 and store it in the soil.

Fortunately, powerful strategies and methods already exist – especially agroforestry in all its forms. Adapted to the local soil and climate, integrating trees within fields and meadows creates some of the most productive and ecologically valuable landscapes worldwide. Silvopastoral systems, which utilize livestock grazing between trees, were developed thousands of years ago, and in some places they are still around. In Spain these mosaic landscapes are known as Dehesa (in Portugal as Montado) and although in decline, they still occupy around 3.5 – 4 million hectares of land in the southern Iberian Peninsula. Most styles of agroforestry not only provide food and wildlife habitat, but also wood for construction and heating. At the same time, they stop erosion, retain humidity in the soil, increase humus and fuel local water cycles. Instead of degrading the land, these systems grow more productive and resilient every year. With each new millimeter of humus, the soil’s capacity to absorb and store water increases; microorganisms build their complex networks of nutrient recycling and distribution; fungal hyphae weave their webs between plants and extend their tentacles into the depths.

This shift requires policies that support and protect small-scale local agrarianism, access to land and resources for people who are willing to build these systems. It requires an education that teaches us to cultivate the necessary skills. And above all, it requires a different way of thinking, new virtues and values. Imagine a society where almost everyone is involved in growing food. Humans once again become a part of the ecosystem, and nature transcends the confines of designated conservation areas. Such a society gives rise to entirely different landscapes – where monocultures fade into obscurity, trees and shrubs proliferate, and the soil recovers. These landscapes create a livable climate, birth their own thunderstorms, cycle the water, and at the same time nourish their inhabitants.

A common argument against agroforestry is that it requires more manual work than industrial agriculture. This might be true for all sustainable food systems, especially for the most productive and ecologically valuable. But once established, a food forest needs less maintenance than almost all other types of farming. Indeed, the meaning of ‘work’ changes: from performing externally determined tasks to a creative flow that synchronizes your activities with those of your family, friends, neighbors and the larger community. This kind of work can help us find meaning in our lives. It might even catalyze profound societal change. Food forests, community-supported agriculture and local distribution networks have the potential to transform not only our landscapes, but our relationship with the natural world, with our food, and with one another.

Sources:
Millán M. Millán, and co-authors: “Climatic Feedbacks and Desertification: The Mediterranean Model” Journal of Climate (2005) 684–701.
Millán M. Millán: “Extreme hydrometeorological events and climate change predictions in Europe.” Journal of Hydrology (2014) 206-224.
Image caption: Depiction of a typical western Mediterranean water cycle. The arrows show the evaporation of water from the sea, swamps and forests, the wind carrying the vapor into the mountains and the returning flow of water back into the soils and swamps. (Illustration by Akvilė Paukštytė based on a drawing by Millán M. Millán)

Projects by Julian Chollet:
https://mikrobiomik.org
https://sarsarale.org
https://climate-landscapes.org
https://bio4climate.org