TY - JOUR A1 - Kriewald, Steffen A1 - Pradhan, Prajal A1 - Costa, Luís Fílípe Carvalho da A1 - Ros, Anselmo Garcia Cantu A1 - Kropp, Jürgen T1 - Hungry cities: how local food self-sufficiency relates to climate change, diets, and urbanisation JF - Environmental research letters N2 - Using a newly developed model approach and combining it with remote sensing, population, and climate data, first insights are provided into how local diets, urbanisation, and climate change relates to local urban food self-sufficiency. In plain terms, by utilizing the global peri-urban (PU) food production potential approximately lbn urban residents (30% of global urban population) can be locally nourished, whereby further urbanisation is by far the largest pressure factor on PU agriculture, followed by a change of diets, and climate change. A simple global food transport model which optimizes transport and neglects differences in local emission intensities indicates that CO2 emissions related to food transport can be reduced by a factor of 10. KW - peri-urban agriculture KW - urbanization KW - dietary patterns KW - agricultural productivity KW - food systems KW - local food Y1 - 2019 U6 - https://doi.org/10.1088/1748-9326/ab2d56 SN - 1748-9326 VL - 14 IS - 9 PB - IOP Publ. Ltd. CY - Bristol ER - TY - GEN A1 - Fluschnik, Till A1 - Kriewald, Steffen A1 - Ros, Anselmo García Cantú A1 - Zhou, Bin A1 - Reusser, Dominik Edwin A1 - Kropp, Jürgen A1 - Rybski, Diego T1 - The size distribution, scaling properties and spatial organization of urban clusters BT - a global and regional percolation perspective N2 - Human development has far-reaching impacts on the surface of the globe. The transformation of natural land cover occurs in different forms, and urban growth is one of the most eminent transformative processes. We analyze global land cover data and extract cities as defined by maximally connected urban clusters. The analysis of the city size distribution for all cities on the globe confirms Zipf’s law. Moreover, by investigating the percolation properties of the clustering of urban areas we assess the closeness to criticality for various countries. At the critical thresholds, the urban land cover of the countries undergoes a transition from separated clusters to a gigantic component on the country scale. We study the Zipf-exponents as a function of the closeness to percolation and find a systematic dependence, which could be the reason for deviating exponents reported in the literature. Moreover, we investigate the average size of the clusters as a function of the proximity to percolation and find country specific behavior. By relating the standard deviation and the average of cluster sizes—analogous to Taylor’s law—we suggest an alternative way to identify the percolation transition. We calculate spatial correlations of the urban land cover and find long-range correlations. Finally, by relating the areas of cities with population figures we address the global aspect of the allometry of cities, finding an exponent δ ≈ 0.85, i.e., large cities have lower densities. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 356 KW - Zipf’s law KW - city clusters KW - percolation KW - Taylor’s law Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-400486 ER - TY - JOUR A1 - Fluschnik, Till A1 - Kriewald, Steffen A1 - Ros, Anselmo Garcia Cantu A1 - Zhou, Bin A1 - Reusser, Dominik Edwin A1 - Kropp, Jürgen A1 - Rybski, Diego T1 - The Size Distribution, Scaling Properties and Spatial Organization of Urban Clusters: A Global and Regional Percolation Perspective JF - ISPRS International Journal of Geo-Information N2 - Human development has far-reaching impacts on the surface of the globe. The transformation of natural land cover occurs in different forms, and urban growth is one of the most eminent transformative processes. We analyze global land cover data and extract cities as defined by maximally connected urban clusters. The analysis of the city size distribution for all cities on the globe confirms Zipf’s law. Moreover, by investigating the percolation properties of the clustering of urban areas we assess the closeness to criticality for various countries. At the critical thresholds, the urban land cover of the countries undergoes a transition from separated clusters to a gigantic component on the country scale. We study the Zipf-exponents as a function of the closeness to percolation and find a systematic dependence, which could be the reason for deviating exponents reported in the literature. Moreover, we investigate the average size of the clusters as a function of the proximity to percolation and find country specific behavior. By relating the standard deviation and the average of cluster sizes—analogous to Taylor’s law—we suggest an alternative way to identify the percolation transition. We calculate spatial correlations of the urban land cover and find long-range correlations. Finally, by relating the areas of cities with population figures we address the global aspect of the allometry of cities, finding an exponent δ ≈ 0.85, i.e., large cities have lower densities. Y1 - 2016 U6 - https://doi.org/10.3390/ijgi5070110 SN - 2220-9964 VL - 5 SP - 1543 EP - 1559 PB - MDPI CY - Basel ER - TY - JOUR A1 - Pradhan, Prajal A1 - Kriewald, Steffen A1 - Costa, Luís Fílípe Carvalho da A1 - Rybski, Diego A1 - Benton, Tim G. A1 - Fischer, Günther A1 - Kropp, Jürgen T1 - Urban food systems: how regionalization can contribute to climate change mitigation JF - Environmental science & technology N2 - Cities will play a key role in the grand challenge of nourishing a growing global population, because, due to their population density, they set the demand. To ensure that food systems are sustainable, as well as nourishing, one solution often suggested is to shorten their supply chains toward a regional rather than a global basis. While such regional systems may have a range of costs and benefits, we investigate the mitigation potential of regionalized urban food systems by examining the greenhouse gas emissions associated with food transport. Using data on food consumption for 7108 urban administrative units (UAUs), we simulate total transport emissions for both regionalized and globalized supply chains. In regionalized systems, the UAUs' demands are fulfilled by peripheral food production, whereas to simulate global supply chains, food demand is met from an international pool (where the origin can be any location globally). We estimate that regionalized systems could reduce current emissions from food transport. However, because longer supply chains benefit from maximizing comparative advantage, this emission reduction would require closing yield gaps, reducing food waste, shifting toward diversified farming, and consuming seasonal produce. Regionalization of food systems will be an essential component to limit global warming to well below 2 degrees C in the future. Y1 - 2020 U6 - https://doi.org/10.1021/acs.est.0c02739 SN - 0013-936X SN - 1520-5851 VL - 54 IS - 17 SP - 10551 EP - 10560 PB - American Chemical Society CY - Washington ER -