You could say soil is one of the most underappreciated resources on the planet. However, that hasn’t always been the case.
In 1937, President Franklin D Roosevelt wrote a letter to all State Governors in the USA including the prophetic phrase, “the nation that destroys its soil destroys itself”. He recognised the risk of soil decline and degradation. But we have continued to plunder rather than preserve. The result is we now face a global soil crisis – however, it is one we have the knowledge to overcome.
Soils are currently facing a fight on many fronts. There is pressure from population growth. From intensive farming, and the damage that does to both soil and water quality. From land management and conservation policies. And, of course, pressure from climate change and extreme events like drought and flooding. There is also soil erosion, listed in a recent analysis by the United Nations as one of the key threats to the soil system.
It is claimed that the generation of 3 cm of topsoil takes 1,000 years. Yet some growers here in the UK have estimated they are losing 1 cm of topsoil from their land each year to erosion. Such a loss is obviously unsustainable, and unless swift action is taken, the quality of soil at our disposal will be degraded to such a degree that it no longer provides the food needed to support our population.
There are other risks too
Soil is a carbon sink, taking greenhouse gases out of the atmosphere and storing them. If our soils are damaged so is their ability to perform this essential task. And the knock-on effects of that – rising global temperatures, increased air and ocean pollution – would place an even greater strain on an already struggling planet.
As with so many aspects of human life, problems created on land can have wider effects. Soil erosion compromises food security but eroded soil can be washed into rivers, reservoirs and the ocean. Once there, the nutrients applied to maximise its benefits to crops can cause significant and lasting harm, affecting water security and ecosystem health.
Soil erosion can also compromise energy security. Soil coming off fields and hillsides turns into silt that can block hydropower dams.
To develop solutions, we need a lot more information, which means employing a whole-system approach involving natural and social scientists, communities, industry and policy makers. Increasingly, and perhaps finally, the scale of this crisis is high on international political agendas.
While we are losing soil through erosion and climate pressures, we are creating waste materials through industrial extraction processes that goes to landfill. These materials, which are of the earth, could be conserved as part of reconstructed soils with the capacity to match the performance of the soils being lost.
Government policies all over the world are starting to reflect why soils need to be protected. They also recognise the risks of not doing that. But to really instigate change requires a significant cultural shift.
The UK Government’s 25-year environment plan aspires to good soil management. However, there's no mention of, for example, moving the status of soils closer to that of water quality and air quality.
In the UK, 55% of the waste going to landfill is soil. It is an indication of the low value accorded to soil by private citizens and nationally. People still see it in this context as waste, not a resource. Its functions are taken for granted, and that is mirrored with soil erosion.
Once the soil leaves a slope and becomes silt, it switches from being perceived as a resource to a pollutant. What it should been seen as is an opportunity, because it still contains the nutrients that we've lost from the land. So there needs to be joined-up thinking to retrieve that sediment, and use it to help regenerate our landscape.
There are so many aspects of soil that are not immediately obvious. When it rains, hard surfaces don't retain water and we could all name locations where flooding is likely to occur. Vegetated gardens, even on a small scale, would make such a difference. Such tangible examples enable people to buy in to the concept of how they can contribute to improved soil health. And that is always going to be one of the challenges we need to overcome. Global targets for soil health and its carbon stores must be part of any serious efforts to reverse its decline.
There is no magic switch, no one-size-fits-all approach, to suddenly solving our soil crisis. Doing so requires leadership and a focused global effort to balance the myriad of economic, environmental and social considerations. But do that we must. Humans have relied on soils for millennia, and we need to find ways to ensure we can rely on them for millennia to come.
Will Blake, Professor of Catchment Science, is an eminent global researcher applying forensic approaches to solve complex issues of soil erosion, its downstream impacts and the associated land management challenges it presents. He is Director of the University's Sustainable Earth Institute. Mark Fitzsimons is Professor of Environmental Chemistry and leads the Biogeochemistry Research Centre. His research interests in nitrogen has spanned the measurement of trace gases in the Southern Ocean, the environmental fate of pharmaceuticals in water and sediments and investigating the chemistry of artificial soils made from inert waste materials.
The COP26 summit, held in Glasgow, Scotland from 31 October to 12 November 2021, brought parties together to accelerate action towards the goals of the Paris Agreement and the UN Framework Convention on climate change.
The University of Plymouth is proud to be a part of the COP26 Universities Network whose mission it is to ensure that the UK academic sector plays its role in delivering a successful COP26, in order to deliver a zero-carbon, resilient world.