Is it sustainable? Do we fight symptoms or the root cause?

Draft Article

Is it sustainable or not? It is a never-ending question. The term "sustainability" remains a disputable topic even today, even when researchers have agreed on one common definition of sustainability more than 30 years ago. Such an ambiguous situation happens since various sustainability aspects can be evaluated differently. 

To make an effort for making sustainability assessment clearer the team of researchers, including, Lelde TimmaElina Dace, Troels Kristensen and Marie Trydeman Knudsen, from various backgrounds and institutions, came together to develop a dynamic model and share their point of view. The results of this cooperation are summarized in this publication for the journal Sustainability.

Where did we start?

In our previous research, we found that the results showing the decay of greenhouse gas emissions in the atmosphere are sensitive to the selected time horizon and thus can lead to contradicting conclusions. Please see the post for this previous research in brief in LinkedIn or full text of the previous publication at the homepage of the Journal Energies

How we proceeded? 

We were curious whether the same findings are valid also for lithosphere ? The answer is – yes, they are!

In our latest research, we show that similar phenomena is found not only in the atmosphere but also in the lithosphere. The soil carbon gains estimated using the decay function are of different magnitude and nature in comparison to the use of constant values. Thus, the results obtained provide a more precise and less optimistic projection of future development than the assessment using constant soil carbon modelling values only.

Why did we look into agriculture and biorefineries?

For the case study, the Danish agriculture system is modelled, since the agriculture practice selected can widely affect the soil carbon changes. Moreover, agriculture in Denmark is a historically well-developed branch of the economy, and this sector is currently exploring ways to transform to more sustainable practices. The substitution of imported soy protein for an animal feed with locally produced "green" protein as a product from green biorefineries is studied as a potentially sustainable solution.

Thus, the developed model covers significant feed flows for animals and animal production, as well as limiting factors in the system, such as ecosystem’s carrying capacity, total available land area, normative regulations, and time delays in decision-making. The development of the Danish agriculture sector is simulated within three possible scenarios and the results assessed in relation to the defined ecosystem’s carrying capacity until 2050. The model is developed using the system dynamics methodology.

The results showed that under the current development, the agriculture sector in Denmark would exploit the ecosystem beyond the carrying capacity shortly after 2030. And that due to the limited agricultural land area, the demand for protein for an animal feed could hardly be satisfied by local biorefineries with "green" protein, i.e., the land area available to grow the "green" protein will be at least six times less than needed to supply protein to feed all animals.

What do we propose?

We propose to always include and consider the limitations of the ecosystems modelled. Let's see on the example of case study performed. We show that the production of "green" animal-grade protein can be innovation for “buying” some additional time before the carrying capacity is reached, see Figure below.

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Figure: Representation of (on the left) the effect of innovation on the exploitation of the ecosystem, (on the right) the exploitation of the ecosystem reaching the ecosystem’s carrying capacity after several innovations. Figure adapted from Rockström et al., 2009Bettencourt et al., 2007, and Sterman, 2000.

As given in the Figure above, technical innovation and productivity increase will mitigate environmental pressure through innovation in agriculture. However, innovation cycles must continually accelerate to sustain the growth and to avoid stagnation or the collapse of the system. Thus, a fundamental shift or ultimate solution to the underlying problem is needed. In this case study, it is the change in demand for animal products.

Major findings

Under increasing pressure on land from intensive biomass production, we would suggest that the solution is not in the technology alone. The way to sustainability is within changes in demand for products, lifestyle, and diet.

The use of the temporal aspects in the impact assessment should be further developed and included in sustainability assessments to yield results with the representation of processes occurring in natural ecosystems. 

The results of this research highlight the importance of considering the ecosystem’s carrying capacity while modelling various innovations and the ecosystem’s services.

Take away message: Is your solution fighting symptoms or root cause?

If you are interested in studying impacts created in other linked systems, please do not hesitate to contact me or my co-authors.

Acknowledgments: The authors are expressing big and hearty “thank you” to Heidi Mai-Lis Andersen for sharing her expert knowledge during the elaboration of the model.

Funding: This research was funded by the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 798365. Contribution of E. Dace to this study was supported by the ERDF Post-doc project No. “Decision Support Tool for an Integrated Food Waste Valorisation System (DeSTInation)”. The revision by L. Timma was supported by the ERDF Post-doc project “Holistic computing within socio-technical systems to design energy efficiency policy tool (HOTSPOT)”.