A lot of neighbourhoods are likely to have a piece of land that has been left unattended or a building that appears to be unoccupied or derelict. And while we may pass those by with a momentary thought about what happened to these or what they could have otherwise been, we are unlikely to think that these are prime examples of how current practices promote and perpetuate unsustainable land development. The problem of unsustainable land development is particularly important with the UN estimating that the footprint of human activities has affected 83% of global land surface[sc:1].
Our land and resources are finite, so we should be using both with great care if we are to address the challenges of urbanisation, changing demographics or climate change. This means careful planning about what land we use and for what reason. However, evidence suggests that our current practices encourage unsustainable land development. While the specific reasons vary in different parts of the world, there are three main ways in which unsustainable land development happens.
Unsustainable agriculture practices
Agriculture is a major land use. Around 50% of the world’s habitable land has already been converted to farming land[sc:2]. More worryingly, modern agriculture exploits land intensively to achieve increased yields. But this has also led to increasing degradation of the land which in turn compromises its productivity in the long term. Unsustainable farming practices, such as the use of pesticides and intensive monocultures, can deplete soil nutrients, while converting land that was covered with local vegetation to arable land can create soil erosion, which then increases flooding and creates other risks.
In addition, agriculture is one of the main emitters of greenhouse gasses. It is responsible for 14% of global greenhouse gas emissions. So the more land that is converted from forests and other wildland for farming purposes, the less our planet has a capacity to absorb carbon[sc:3].
Buildings and infrastructure
Whereas in a lot of developing countries, land is primarily converted into arable land, in other regions such as Europe, land is needed to develop infrastructure, such as transport links and housing[sc:4]. While this provides much needed services to urban areas and connecting cities across countries, the land is covered with different impervious surfaces (e.g. cement) which leads to the disruption of the natural cycles with implications for soil quality and erosion. The development of transport infrastructure and other built-up areas creates what experts have called “landscape fragmentation”. Our roads, bridges and other buildings are often built on areas inhabited by different species. By building on those areas, the natural links and balance of these ecosystems is compromised with negative impacts on biodiversity and the preservation of ecological habitats. This is why planners and policy-makers are increasingly promoting “green infrastructure” approaches where the development of infrastructure is adapted to respect local biodiversity and habitat specificities.
Resource extraction and pollution
Another important cause of unsustainable land development is how we use the land we claim for human activities such as agriculture or industrial production and in what state we leave the land when that activity is over. In many cases, extractive industries such as mining, leave the land in a very poor state. After mining operations are over, the land is often left abandoned with deteriorated materials and often of toxic chemical composition, which hinder the rewilding of these areas[sc:5].
Similarly, industrial activity can sometimes emit pollutants that enter land, air and water; historically this has been a concern in many areas in Europe and continues to be one globally. Industrial pollutants particularly affect nearby areas and as a result of unregulated industrial activity many areas have been polluted making them unsuitable for other activities and also necessitating investments for their clean up. For instance, in Dzerzhinsk, Russia, the death rate is considerably higher compared to the Russian average, as a result of the pollution of local water supplies by chemicals manufacturing[sc:6].