A dark future sprouting from sealed soil

A view of Quito (Ecuador). Credit: Martin Mergili. Click on the image to see the original picture and details in Imaggeo.

Every year in Europe, soils covering an area larger than the city of Berlin are lost to urban sprawl and transport infrastructure. This unsustainable trend threatens the availability of fertile soils and groundwater reservoirs for future generations. A new report made public today by the European Commission recommends a three-tiered approach focused on limiting the progression of soil sealing, mitigating its effects and compensating valuable soil losses by action in other areas.

Environment: Soil sealing in the EU threatens the availability of ecosystem services. European Commission – IP/11/624   23/05/2011

You live on sealed soil

Look out your window. If you do not live isolated in the countryside, it will be difficult that most of which you can see is not sealed floor. Most land around you is covered by buildings or pavement. It is normal, you live in a town or a village. There is much more space out there! Is there much space out there?

Decay. Credit: Marcel Van Oijen. Click on the image to see the original picture and details in Imaggeo.

Soil sealing occurs when it is covered with impervious surfaces such as asphalt or concrete. These materials are necessary for construction of buildings and road materials, but its use implies the disappearance of agricultural resources and food production, significant changes in the hydrological processes at catchment scales as well as the loss the most important soil functions as habitat and biological support, biomass production, gene pool, sink of greenhouse gases, filtration and transformation of substances and protection of groundwater and the food chain …

Organic farming. Credit: Kristof Van Oost. Click on the image to see the original picture and details in Imaggeo.
Soil products. Credit: Artemi Cerdà. Click on the image to see the original picture and details in Imaggeo.

Even in cities, unsealed floor areas are necessary. because rain water can not flow through paved surfaces, and the ability of the sewerage system is overloaded.

A problem linked to social inequality

The rapid occupation of land for buildings has become one of the most important environmental problems. Due to migration from rural areas to the big cities and the intense changes of use from the second half of the twentieth century until now, the area of ​​land devoted to agriculture or natural vegetation is declining. And the reasons are obvious: the private economic benefit obtained from construction is much higher than from farming. Besides food products can be imported from other countries. But … is this a sustainable policy? How long?

Just one example: in Andalusia, where I live, land consumption per capita has increased by 4 in the last 50 years, from 87 m2 in 1956 to more than 337 m2 in 2007. Although causes vary from one region to another (industrial and commercial growth, infrastructure construction, mining activities, landfills, etc.), in all cases urban expansion is the main cause of soil sealing.

Rural roads change the landscape. Credit: Artemi Cerdà. Click on the image to see the original picture and details in Imaggeo.

And it’s not just a problem in the south of Europe. In small countries like Austria, only one third of the land can be used for construction. But urban and industrial expansion continues (the Viennese population grows at a rate of 20,000 people per year), so that in many parts of the country there is not much space and urban planning should be seriously analyzed.

Land abandonment is a key factor of Mediterranean Landscapes. Credit: Artemi Cerdà. Click on the image to see the original picture and details in Imaggeo.

In the EU, At least 275 ha of soil per day were lost, amounting to 1,000 km² per year Between 1990 and 2000, although this trend has been reduced to 252 ha per day in recent years, but the rate of land consumption is still worrying. Between 2000 and 2006, the EU average increase in artificial areas was 3%, with increases attaining 14% in Ireland and Cyprus and 15% in Spain (read more here).

May we get rid of soil sealing?

Obviously, people need to be fed. And for that we need transport infrastructures and consequent soil sealing. We also need infrastructures for the processing of raw materials. As a colleague says, “processes generate structures“. Therefore, we can not do without soil sealing. But we can achieve a balance.

How to? Discovering the causes

The poor generally have access only to areas that have higher risk for health and income generation. And they generally lack the resources to reduce the exposure to the risk or to invest in alleviating the causes of such risk. Environmental degradation therefore can affect the health and nutrition status of the poor and lower their productivity. This can happen both directly through, for example, lower yields per unit of labor or land because of reduced soil quality, and indirectly through the reduced physical capacity of labor to produce because of malnutrition and poor health. Even in cases where the poor are healthy labor productivity can be low due to increased time being allocated to less-productive activities such as fuel wood collection and away from agriculture and other income generating activities.

Consultative Group on International Agricultural Research. CGIAR research priorities for marginal lands. Document No.:SDR/TAC:IAR/99/12.

Zooming in community. Credit: Veilo Coviello. Click on the image to see the original picture and details in Imaggeo.

In current systems, urban population, for which most of these infrastructures are intended, is mostly concentrated in points far from the sources of production. The rural population migrates to cities due to low access to education, health care and, above all, low incomes and job expectations.

Ploughing in Central rift valley, Ethiopia. Credit: Saskia Keesstra. Click on the image to see the original picture and details in Imaggeo.

Although the consequences of this migration are not as severe (they are) in the so-called First World, the urban agglomeration does not solve these problems. More, it contributes to create large pockets of poverty in the periphery of cities. Here we have an interesting political issue. Are we heading towards a future of smart cities for the ruling class surrounded by belts of hunger, poverty and insecurity?

Getting crowded. Credit: Albin Hammerle. Click on the image to see the original picture and details in Imaggeo.

Read more


This post has been also published in the EGU Blog Network.


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