Biodiversity Part 1: Our Impact on Biodiversity
Biodiversity, agriculture and food are very current topics, within the field of sustainability and outside of it. They have a strong effect on GHG emissions, climate change and global warming, which means it is essential for policy makers to give these topics some thought. Unfortunately, these topics require a lot of nuanced thinking. In this series, we address biodiversity impact assessment. Part 1: how do you even define ‘nature’?
How To Define ‘Nature’?
One reason we care about the environmental impacts of our choices is because they affect natural systems. But how do we quantify this effect, and how do we assess our impact? And what do we actually mean with the word ‘nature’?
One way to look at nature is utilitarian: what does it bring us? But we can also see nature as having an intrinsic value; something we need to protect, whatever its value. Both viewpoints are defendable.
Utilitarian approach for assessing natural ecosystems
Natural ecosystems purify the air, help to keep the climate stable, and provide an almost infinite range of useful resources. If we damage these functions, we will create expensive problems. Many so-called ‘natural capital methods’ are based on assessing the economic costs that would occur if nature is damaged. We also see this approach in the PEF: land use is expressed in terms of soil organic matter, which relates to the fertility of soils.
Nature has an intrinsic value
In the intrinsic value view, we try to describe nature in a more abstract way, without considering the direct utility: we can focus on habitat diversity, gene pool diversity or biodiversity.
What’s common between both views is that a higher diversity means a larger resilience to changes.
Biodiversity As A Proxy
In LCIA endpoint modelling, we focus on biodiversity as a proxy to express the impacts we have on nature. The Eco-indicator, ReCiPe and Impact 2000 methods are examples of endpoint modelling for impact assessment.
In these methods the damage to diversity can be described as ‘the fraction of species that has been lost in comparison with a natural or undisturbed area’. This approach also has a few complications, as sometimes we see species appearing that do not belong in an area, for instance invasive species. In the case of eutrophication or climate change, we sometimes find more species instead of fewer, but we then often find that these are not the ‘desired’ species. We want to protect areas with low nutrient levels, as these often contain very rare and valuable species. We don’t want those species to be replaced by common species such as grasses. In this perspective, we try to focus on the species pool that belong to a certain habitat.
The diagram below illustrates how a method like ReCiPe connects emissions and land use to the loss of biodiversity: it calculates the impacts on land and in water via various impact categories in a two-step approach. The unit for biodiversity for impact assessment is PDF.m2.yr, with PDF as the potentially disappeared fraction of species. Loss of species is calculated in a certain area (hence m2) or Volume (hence m3), during a certain time (hence the addition of years).
Biodiversity: The Next Hot Topic?
The protection of biodiversity is getting a lot of attention in international policy making, as the loss of biodiversity is seen as a major risk for many regions in the world. For instance, we are seeing much interest from the financial sector, looking to understand how safe their investments are in companies with a big impact on biodiversity. Biodiversity may be the next hype, after the concerns financial institutions have about companies that invest in activities that lead to climate change.
We are also seeing a lot of interest from another community of experts: those who want to assess natural capital costs. They typically assess biodiversity impacts and then extrapolate this to financial costs. Biodiversity assessment is the step before Natural Capital Assessment.
Are We Oversimplifying? Your Verdict
Of course, trying to understand the impact on ‘nature’ by counting species is a simplification. ‘Nature’ is a concept with so many aspects that it is difficult, or even impossible, to express it as a single parameter. However, when we started the development of the Eco-indicator 95 method, we agreed with those who said it is impossible to measure nature, but we also agreed with those who maintained that it is necessary to try. Without an indicator, we cannot assess the impacts of what we do. We do not claim that this metric is perfect, but at least it is workable.
In the next two articles, we will clarify how we relate the impact of climate change and land use to biodiversity. This will allow you to form your own opinion: are you in the group that thinks measuring nature is impossible? Or the group that thinks that some measurement, even if imperfect, is possible and necessary? We need both groups to foster the dialogue.