The world is facing a very real emergency with accelerating soil erosion. So where is the same sense of urgency that we see for climate change or antibiotic resistance? Soil erosion threatens a critical natural resource for growing food, as it sustains 95% of global food production through crops and livestock raising. Moreover, soils deliver wider but less obvious benefits, such as storing water to reduce flooding, water purification, nutrient cycling and carbon storage to mitigate CO2 emissions.
The problem, however, is not confined to the land. River systems connect the land to the sea and eroded soil washes into waterways, impacting a wide range of river basin ecosystem services. For example, soil erosion can cause water pollution and ecological impacts of excessive siltation, which also negatively affects hydropower generation.
I have witnessed the scale and complexity of soil erosion challenges in different parts of the world. It is very clear to me that to understand and solve this problem, we need to understand interconnected and complex dimensions between people, land and water.
It’s all too easy to pin a soil erosion problem on specific land management practices. For example, ‘overgrazing’ is often cited as the cause of soil erosion in sub-Saharan Africa, but our work has shown that overgrazing itself is a symptom of deeper, much more complex socio-economic and natural drivers. This is partially related to pastoral communities transitioning, through necessity, to more sedentary livelihoods, and is also subject to the wider pressures of climate change and population expansion. Equally, there is sometimes a false perception that soil is a renewable resource and we can simply plough out the scars in the landscape ready for the next crop. As researchers, we need to think outside of conventional disciplinary boundaries to understand why decisions that cause these problems are still being repeated.
We should also challenge ourselves as consumers to change our behaviour.
The plight of the orang-utan focussed consumer awareness of sustainable palm oil’s presence in everyday supermarket products. Hardwood certification schemes allow us to buy garden furniture with a clear conscience. That consumer awareness is missing for soil erosion, and we don’t currently have the information on supermarket products to make informed decisions. Is it now time to factor soil erosion into the equation of what constitutes a ‘sustainable’ or ‘eco-friendly’ product?
The soil erosion problem is not the result of any one product. Avocado production has come under recent scrutiny for its links to water shortages, deforestation and ‘environmental devastation’, providing an interesting example to explore our role as consumers. Increasing demand for high-value products inevitably fuels demand for expanding growing space. A recent global-scale analysis showed that, while sharp increases in resource consumption over recent decades mirror population growth, expansion of domesticated land has slowed. This is not because we are being more mindful of the conservation debates alluded to previously, but because there is little appropriate growing space left to move into.
The limited land we do have available to convert is harder to work and, unfortunately, at greater risk of erosion. I’ve seen first-hand how technological advances allow us to push into more marginal, steeper land that, once cleared of natural vegetation for developments like avocado or olive plantations, is highly erodible. Soil erosion reduces soil quality, increasing reliance on inorganic fertilisers that in turn increases soil erodibility – and a vicious circle develops.
Soil erosion is everyone’s problem. People are intrinsically linked to landscape and decision-making at all levels. All of us, from politicians to farmers to consumers, have a stake in the soil erosion challenges we face. We must act now.