Obscure impacts demystified: Land use
Another important topic in obscure impact categories is land use. Unlike some other categories such as eutrophication, land use almost sounds too straightforward. But there is more to land use than one might think, as this article shows.
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Our planet is busy. Over 7 billion people, around 20 quintillion animals and even more plants reside on planet Earth. And yet, only a small part of the planet’s surface can be used by us humans. Only about 30% of the surface is not covered by water. If we exclude deserts and mountain areas, that leaves 71% of this surface as habitable land for humans – that’s 21% of the Earth’s crust. Given the world population, this comes down to just over 1 hectare of land per person if we ignore that all other species are also dependent on habitable land.
Chances are pretty high you don’t own such a stretch of land. At least, I don’t. Yet, we consume and produce goods and services at a significantly larger share of land than we are actually entitled to. The rising pressure on available land is becoming increasingly problematic, which causes a variety of environmental problems. What are these environmental problems? How does life cycle assessment (LCA) treat land use, and how can we lower the share of the planet that we use?
What is land use?
From its name, it is fairly easy to guess what this impact category is about: how much land is used. However, in LCA, we do not just consider the amount of land that is used, but even more how land is used. More specifically, two kinds of land use are defined.
The first category is about the amount of land that is occupied for a certain period to produce a product. For example, to produce 6500 kg of flour, one might need around 1 hectare of agricultural land for a full year, i.e. 1 hectare year. The second category is about the amount of land that needs to be transformed from one kind to another. For example, for this same 1 kg of flour, one might also need to convert an extra 150 m2 from grass land to agricultural land, suitable for the cultivation of the wheat for the flour. Grass and agricultural land are some of the many examples of land use, which also includes forest, urban, industrial land and many more. Within each category, there are multiple subcategories. Tropical rain forest, taiga and boreal forests all fall under forest land.
Land-use changes might not always directly be a result of choosing a certain input for your product. Therefore, there is a distinction between direct (dLUC) and indirect land-use change (iLUC). Direct changes arise when the input you choose directly causes the change to happen. Indirect changes occur further up the supply chain.
For example, one of your inputs is vegetable oil from rapeseed. This oil has already been produced, so will not cause any direct land use changes to happen. However, with the choice for rapeseed oil, the total demand for vegetable oil increases. To meet the extra demand, additional vegetable oil has to be produced. This will most likely be done in the cheapest and easiest way, the so-called marginal technology, which is palm oil from South-East Asia. As a consequence, rainforests might be cleared to accommodate the indirectly increased demand for palm oil – and this is indirect land-use change.
But why is it important to even know how land is used with this much detail? Well, every type of land use has a different direct interaction with its immediate environment. The interaction of forest land with animals, plants, soil and water is quite different than urban land. As a consequence, every land use has its own environmental characteristics. Therefore, to fully understand the environmental impacts of the studied system, it is necessary to determine how land is used throughout the value chain.
Why is it a problem?
As said, every land use has its own environmental characteristics. That means every land-use category performs different functions, for both humankind and other living species. The numerous functions relevant to humankind can be categorized into three subcategories: provisioning (e.g. supplying food and wood), regulating (e.g. flood regulation or water purification), and cultural (e.g. aesthetic and recreational functions). Apart from these human-centred functions, ecosystems of course also provide functions to all other living beings on planet Earth.
Whenever a piece of land changes from one type to another, the functions of that land change with it. On a small scale, this is not necessarily problematic. However, large-scale land transformations might result in dramatic loss of certain functions, endangering those depending on the functions. Reduction of the functions that land performs can ultimately affect human health, decrease the quality of ecosystems and deplete resources. The potential consequences of dramatic land-use change are as numerous as the functions of land use themselves.
What causes land-use change?
Whenever we think of land-use change, we might picture large stretches of the rainforests being chopped down by heavy machinery, like the picture above. Such deforestation might be, but is not always, caused by the demand for wood. The primary reason for forests to be cleared is agriculture; to make space for our cattle to graze and crops to grow. The figure below shows that up to 50% of habitable land is used for agriculture. More interestingly, 77% of agricultural land is used for livestock whereas while it accounts for a much smaller share of the global calorie supply (18%) and global protein supply (37%).
The disappearance of rainforests in South-America and Asia threatens the existence of many species, like orangutans. But it is important to realize that deforestation is not just a problem in the rainforests, but also in other places all around the world. For instance, it is estimated that the current size of forests in Europe is just half of what was there 6.000 years ago. A local example of the consequences of deforestation is the Italian island Sicily. Since Roman times, the island has been heavily deforested, until hardly any forest is left nowadays. The lack of trees promotes desertification in the area, which results in water shortages and dry rivers and heavily affects agriculture and nature on the island. This shows that large-scale deforestation is not only a problem for those living in the forest, but to all those depending on the ecosystem, including humans.
Whenever forests are converted to agricultural land, more than only the functionality of the forests: intensive agriculture tends to further deteriorate the functionality of the land. Practices such as using heavy machinery, producing single crops repeatedly and using pesticides make the soil vulnerable to erosion, deplete the nutrients and harm all species living on the land.
Measuring land use
As said, the impact from land use is not only about how much land is used, but also how it is used. There are many ways to measure land use impacts, each with their own land-use models and corresponding indicators. That means the results have different meanings.
To give a few examples, in ReCiPe2016, land use is quantified as Agricultural Land Occupation. Rather straightforward, this measures the amount of agricultural land that is used for a certain time. Alternatively, the ILCD recommendations propose to quantify the Soil Organic Matter loss. This indicator reflects many, although not all, effects of land transformation and occupation on soil quality. Further, Environmental Footprint 3.0 recently developed a new dimensionless aggregated indicator, the Soil Quality Index, taking into account many soil properties. Finally, Abhishek Chaudhary has done some important work on the development of characterization factors for projecting the biodiversity impact of land use associated with a products’ life cycle. This is very relevant considering that anthropogenically driven change in land cover is the most important driver for biodiversity loss in terrestrial ecosystems. In each case, it is up to the LCA practitioner to decide which method and indicator works best in terms of relevance, consistency, data collection and the extent to which the model is mature and up to date.
How can we stop land-use impacts?
Unlike some of the other impact categories, land use can be impacted by your own consumption pattern. An effective and straightforward place to start is to inform yourself about sustainable and unsustainable products. Knowing that livestock occupies nearly 80% of global agricultural land but provides less than 20% of the global calorie supply, changing to a plant-based diet holds a large impact reduction potential. Other ways to reduce your impact significantly is to switch to certified palm oil and restrict yourself to wood products with internationally recognized labels for sustainable forestry, named FSC or PEFC, or to support organizations that fight deforestation like the Rainforest Alliance.
At the business and industry level, it is important to quantify land-use impact throughout the supply chain of a product or service, since harmful land use often happens far away, upstream in the supply chain. Using LCA, we can provide the insights necessary to effectively determine land-use impacts.
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“Meeting the needs of current generation, without compromising the ability of future generations to meet their needs”. The quote from the Norwegian prime-minister Gro Harlem Brundtland defined sustainable development in 1987 and, despite being written 8 years before my birth, has been relevant ever since, both to the world and to me. At the moment societies are still struggling to be sustainable and we are putting great pressure at planet Earth’s carrying capacity, endangering the ability of future generations to meet their needs. To relieve the planet from these pressures, I dedicate myself to support green decision making, allowing for real sustainable development to happen and, most important, for future generations that can meet their needs!
Wouter van Kootwijk
Sustainability poses many complex challenges to our current and future society. These challenges require us to collaborate and to make informed decisions from an environmental, social and economic perspective. I believe that LCA can provide us with the insights needed to make such decisions. By identifying and acting on sustainable opportunities, we can create a prosperous and flourishing world in which we live within the limits of our planet and continuously improve well-being.