The way we strive to capture the Nexus in the MAGIC project is with the aim of describing the key metabolic processes that make it possible for our societies to reproduce themselves. We are aware that these processes operate concurrently in different spheres and at various temporal as well as spatial scales; the MuSIASEM approach is precisely about addressing the relationships they show and highlighting them in story-telling to inform social debate and policy making.
Land should represent an unforgettable fund in resource accounting. As a fund, land reflects not only the Earth's surface, but also land uses and the various land management systems that are the interactions of human activities with environmental resources. Those complex interactions make any attempt to model the processes even more challenging; nonetheless, it is useful to envision a conceptual model that describes land systems as a coupled human-environment system (Figure 1).
Land and land systems link to resource accounting and to the operation of multi-scale integrated assessment for nexus issues in a variety of ways. Land represents a geographical area, defined by relevant boundaries; a production factor, in the sense that Ricardo, in the early 19th century, described land, labour and capital to identify a set of resources and their uses; and a set of geographically distributed human and environmental funds, qualities and processes. As a geographic area, land gives a place-based foundation for analysis of how nexus issues affecting specific combinations of people and environments. As a production factor and set of human and environmental funds, land embodies ideas of natural capital as the fund that yields a flow of ecosystem goods and services. We argue that the roles and importance of natural capital are to be included in MuSIASEM, as a tool for investigating sustainability, through land systems and land use.
Understanding land use in sustainability and the nexus face a number of issues: Figure 1 could offer a glimpse of how many sub-systems, roles and processes express their interactions in the frame of land system.
(From Aspinall, R. J. and Staiano, M. (2017) A conceptual model for land systems dynamics as a coupled human-environment system. LAND, 6, 81 https://www.mdpi.com/2073-445X/6/4/81)
Figure 1: A conceptual model of land system1
So, where to start? In the Figure 2 we present the latitudinal distribution of land cover of the Earth, along with graphs of population density and elevation; this visualization clearly shows that also at global scale there are many ways to explore and examine data for human and environment systems and the way they interact, as we attempt to establish a sustainable future.
The upper frame of the Figure 2 includes a smooth graph of total population by latitude (based on 0.5-arc-minute resolution data) along with the plot of maximum and mean elevation. It gives a picture of the distribution of population on colonized land by latitude (see the labels of main continental areas under the graphs). In the lower frame the distribution of land cover by latitude is depicted. Even at a coarse scale it is easy to see how limited the potential area for expansion for cropland is and the link between the location of pasture land and higher population densities. From the combined reading of the two frames it appears clear that orography and climate leave limited opportunities for big adjustments at the global scale.
Figure 2: A visualization of Earth elevation (maximum and mean), population (upper frame) and area of land cover types by latitude (lower frame).
Land (through soil, land cover and land use) delivers a vast set of vital functions, primary productivity, water purification and regulation, carbon cycling and storage, recycling of other nutrients and wastes, habitats for biodiversity and cultural services (like landscape aesthetics and sense of place), that all sustain and enrich our lives.
Metaphorically speaking, a working, balanced nexus that offers the possibility of sustainability, can be thought of as orchestral music played on a well-mixed record. All the parts are harmonized so that we can really enjoy the music, being at the same time able to listen to a single instrument and appreciate the richness of the ensemble. For people used to playing vinyl LPs, it is easy to be enchanted by the lucid disk calmly spinning and disregard the pivot at the centre of the turntable… The current issue of The Nexus Times highlights how land could play that “pivotal” role in shaping a way to better understand and respond to the challenges of achieving sustainability within the water, energy, food and environment nexus.
European Commission (EC) Regulation No 525/2013 of the European Parliament and the Council on a Mechanism for Monitoring and Reporting Greenhouse Gas Emissions and Other Information Relevant to Climate Change, Brussels (2016), http://ec.europa.eu/transparency/regdoc/rep/10102/2016/EN/SWD-2016-249-F1-EN-MAIN-PART-1.PDF
Lorenz, K, Lal, R, Ehlers, K. (2109). Soil organic carbon stock as an indicator for monitoring land and soil degradation in relation to United Nations' Sustainable Development Goals. Land Degrad Dev. 2019; 30: 824– 838. doi.org/10.1002/ldr.3270
O’Sullivan, L., Wall, D., Creamer, R., Bampa, F., & Schulte, R. P. O. (2018). Functional land management: Bridging the think-do-gap using a multi-stakeholder science policy interface. Ambio, 47(2), 216-230. doi.org/10.1007/s13280-017-0983-x
Schulte, R. P. O., Bampa, F., Bardy, M., Coyle, C., Creamer, R. E., Fealy, R., et al. (2015). Making the most of our land: Managing soil functions from local to continental scale, Frontiers in Environmental Science, 3, 81. doi.org/10.3389/fenvs.2015.0008
Center for International Earth Science Information Network - CIESIN - Columbia University. 2018. Gridded Population of the World, Version 4 (GPWv4): Population Count, Revision 11. Palisades, NY: NASA Socioeconomic Data and Applications Center (SEDAC). https://doi.org/10.7927/H4JW8BX5