@article{HicPradhanRybskietal.2016, author = {Hic, Ceren and Pradhan, Prajal and Rybski, Diego and Kropp, J{\"u}rgen}, title = {Food Surplus and Its Climate Burdens}, series = {Geological Society of America bulletin}, volume = {50}, journal = {Geological Society of America bulletin}, publisher = {American Chemical Society}, address = {Washington}, issn = {0013-936X}, doi = {10.1021/acs.est.5b05088}, pages = {4269 -- 4277}, year = {2016}, abstract = {Avoiding food loss and waste may counteract the increasing food demand and reduce greenhouse gas (GHG) emissions from the agricultural sector. This is crucial because of limited options available to increase food production. In the year 2010, food availability was 20\% higher than was required on a global scale. Thus, a more sustainable food production and adjusted consumption would have positive environmental effects. This study provides a systematic approach to estimate consumer level food waste on a country scale and globally, based on food availability and requirements. The food requirement estimation considers demographic development, body weights, and physical activity levels. Surplus between food availability and requirements of a given country is considered as food waste. The global food requirement changed from 2,300 kcal/cap/day to 2,400 kcal/cap/day during the last 50 years, while food surplus grew from 310 kcal/cap/day to 510 kcal/cap/day. Similarly, GHG emissions related to the food surplus increased from 130 Mt CO2eq/yr to 530 Mt CO2eq/yr, an increase of more than 300\%. Moreover, the global food surplus may increase up to 850 kcal/cap/day, while the total food requirement will increase only by 2\%-20\% by 2050. Consequently, GHG emissions associated with the food waste may also increase tremendously to 1.9-2.5 Gt CO2eq/yr.}, language = {en} } @article{ZhouLauwaetHooyberghsetal.2016, author = {Zhou, Bin and Lauwaet, Dirk and Hooyberghs, Hans and De Ridder, Koen and Kropp, J{\"u}rgen and Rybski, Diego}, title = {Assessing Seasonality in the Surface Urban Heat Island of London}, series = {Journal of applied meteorology and climatology}, volume = {55}, journal = {Journal of applied meteorology and climatology}, publisher = {American Meteorological Soc.}, address = {Boston}, issn = {1558-8424}, doi = {10.1175/JAMC-D-15-0041.1}, pages = {493 -- 505}, year = {2016}, abstract = {This paper assesses the seasonality of the urban heat island (UHI) effect in the Greater London area (United Kingdom). Combining satellite-based observations and urban boundary layer climate modeling with the UrbClim model, the authors are able to address the seasonality of UHI intensity, on the basis of both land surface temperature (LST) and 2-m air temperature, for four individual times of the day (0130, 1030, 1330, and 2230 local time) and the daily means derived from them. An objective of this paper is to investigate whether the UHI intensities that are based on both quantities exhibit a similar hysteresis-like trajectory that is observed for LST when plotting the UHI intensity against the background temperature. The results show that the UrbClim model can satisfactorily reproduce both the observed urban rural LSTs and 2-m air temperatures as well as their differences and the hysteresis in the surface UHI. The hysteresis-like seasonality is largely absent in both the observed and modeled 2-m air temperatures, however. A sensitivity simulation of the UHI intensity to incoming solar radiation suggests that the hysteresis of the LST can mainly be attributed to the seasonal variation in incoming solar radiation.}, language = {en} } @article{BoettleRybskiKropp2016, author = {Boettle, Markus and Rybski, Diego and Kropp, J{\"u}rgen}, title = {Quantifying the effect of sea level rise and flood defence-a point process perspective on coastal flood damage}, series = {Natural hazards and earth system sciences}, volume = {16}, journal = {Natural hazards and earth system sciences}, publisher = {Copernicus}, address = {G{\"o}ttingen}, issn = {1561-8633}, doi = {10.5194/nhess-16-559-2016}, pages = {559 -- 576}, year = {2016}, abstract = {In contrast to recent advances in projecting sea levels, estimations about the economic impact of sea level rise are vague. Nonetheless, they are of great importance for policy making with regard to adaptation and greenhouse-gas mitigation. Since the damage is mainly caused by extreme events, we propose a stochastic framework to estimate the monetary losses from coastal floods in a confined region. For this purpose, we follow a Peak-over-Threshold approach employing a Poisson point process and the Generalised Pareto Distribution. By considering the effect of sea level rise as well as potential adaptation scenarios on the involved parameters, we are able to study the development of the annual damage. An application to the city of Copenhagen shows that a doubling of losses can be expected from a mean sea level increase of only 11 cm. In general, we find that for varying parameters the expected losses can be well approximated by one of three analytical expressions depending on the extreme value parameters. These findings reveal the complex interplay of the involved parameters and allow conclusions of fundamental relevance. For instance, we show that the damage typically increases faster than the sea level rise itself. This in turn can be of great importance for the assessment of sea level rise impacts on the global scale. Our results are accompanied by an assessment of uncertainty, which reflects the stochastic nature of extreme events. While the absolute value of uncertainty about the flood damage increases with rising mean sea levels, we find that it decreases in relation to the expected damage.}, language = {en} } @article{LenkRybskiHeidrichetal.2017, author = {Lenk, Stephan and Rybski, Diego and Heidrich, Oliver and Dawson, Richard J. and Kropp, J{\"u}rgen}, title = {Costs of sea dikes - regressions and uncertainty estimates}, series = {Natural hazards and earth system sciences}, volume = {17}, journal = {Natural hazards and earth system sciences}, publisher = {Copernicus}, address = {G{\"o}ttingen}, issn = {1561-8633}, doi = {10.5194/nhess-17-765-2017}, pages = {765 -- 779}, year = {2017}, abstract = {Failure to consider the costs of adaptation strategies can be seen by decision makers as a barrier to implementing coastal protection measures. In order to validate adaptation strategies to sea-level rise in the form of coastal protection, a consistent and repeatable assessment of the costs is necessary. This paper significantly extends current knowledge on cost estimates by developing - and implementing using real coastal dike data - probabilistic functions of dike costs. Data from Canada and the Netherlands are analysed and related to published studies from the US, UK, and Vietnam in order to provide a reproducible estimate of typical sea dike costs and their uncertainty. We plot the costs divided by dike length as a function of height and test four different regression models. Our analysis shows that a linear function without intercept is sufficient to model the costs, i.e. fixed costs and higher-order contributions such as that due to the volume of core fill material are less significant. We also characterise the spread around the regression models which represents an uncertainty stemming from factors beyond dike length and height. Drawing an analogy with project cost overruns, we employ log-normal distributions and calculate that the range between 3x and x/3 contains 95\% of the data, where x represents the corresponding regression value. We compare our estimates with previously published unit costs for other countries. We note that the unit costs depend not only on the country and land use (urban/non-urban) of the sites where the dikes are being constructed but also on characteristics included in the costs, e.g. property acquisition, utility relocation, and project management. This paper gives decision makers an order of magnitude on the protection costs, which can help to remove potential barriers to develop-ing adaptation strategies. Although the focus of this research is sea dikes, our approach is applicable and transferable to other adaptation measures.}, language = {en} } @article{ZhouRybskiKropp2017, author = {Zhou, Bin and Rybski, Diego and Kropp, J{\"u}rgen}, title = {The role of city size and urban form in the surface urban heat island}, series = {Scientific reports}, volume = {7}, journal = {Scientific reports}, publisher = {Nature Publ. Group}, address = {London}, issn = {2045-2322}, doi = {10.1038/s41598-017-04242-2}, pages = {9}, year = {2017}, abstract = {Urban climate is determined by a variety of factors, whose knowledge can help to attenuate heat stress in the context of ongoing urbanization and climate change. We study the influence of city size and urban form on the Urban Heat Island (UHI) phenomenon in Europe and find a complex interplay between UHI intensity and city size, fractality, and anisometry. Due to correlations among these urban factors, interactions in the multi-linear regression need to be taken into account. We find that among the largest 5,000 cities, the UHI intensity increases with the logarithm of the city size and with the fractal dimension, but decreases with the logarithm of the anisometry. Typically, the size has the strongest influence, followed by the compactness, and the smallest is the influence of the degree to which the cities stretch. Accordingly, from the point of view of UHI alleviation, small, disperse, and stretched cities are preferable. However, such recommendations need to be balanced against e.g. positive agglomeration effects of large cities. Therefore, trade-offs must be made regarding local and global aims.}, language = {en} } @misc{GudipudiRybskiLuedekeetal.2019, author = {Gudipudi, Venkata Ramana and Rybski, Diego and L{\"u}deke, Matthias K. B. and Kropp, J{\"u}rgen}, title = {Urban emission scaling - Research insights and a way forward}, series = {Environment and Planning B: Urban Analytics and City Science}, volume = {46}, journal = {Environment and Planning B: Urban Analytics and City Science}, number = {9}, publisher = {Sage Publ.}, address = {London}, issn = {2399-8083}, doi = {10.1177/2399808319825867}, pages = {1678 -- 1683}, year = {2019}, language = {en} } @article{PradhanCostaRybskietal.2017, author = {Pradhan, Prajal and Costa, Lu{\´i}s F{\´i}l{\´i}pe Carvalho da and Rybski, Diego and Lucht, Wolfgang and Kropp, J{\"u}rgen}, title = {A Systematic Study of Sustainable Development Goal (SDG) Interactions}, series = {Earths Future}, volume = {5}, journal = {Earths Future}, publisher = {Wiley}, address = {Hoboken}, issn = {2328-4277}, doi = {10.1002/2017EF000632}, pages = {1169 -- 1179}, year = {2017}, abstract = {Sustainable development goals (SDGs) have set the 2030 agenda to transform our world by tackling multiple challenges humankind is facing to ensure well-being, economic prosperity, and environmental protection. In contrast to conventional development agendas focusing on a restricted set of dimensions, the SDGs provide a holistic and multidimensional view on development. Hence, interactions among the SDGs may cause diverging results. To analyze the SDG interactions we systematize the identification of synergies and trade-offs using official SDG indicator data for 227 countries. A significant positive correlation between a pair of SDG indicators is classified as a synergy while a significant negative correlation is classified as a trade-off. We rank synergies and trade-offs between SDGs pairs on global and country scales in order to identify the most frequent SDG interactions. For a given SDG, positive correlations between indicator pairs were found to outweigh the negative ones in most countries. Among SDGs the positive and negative correlations between indicator pairs allowed for the identification of particular global patterns. SDG 1 (No poverty) has synergetic relationship with most of the other goals, whereas SDG 12 (Responsible consumption and production) is the goal most commonly associated with trade-offs. The attainment of the SDG agenda will greatly depend on whether the identified synergies among the goals can be leveraged. In addition, the highlighted trade-offs, which constitute obstacles in achieving the SDGs, need to be negotiated and made structurally nonobstructive by deeper changes in the current strategies.}, language = {en} } @article{RibeiroRybskiKropp2019, author = {Ribeiro, Haroldo V. and Rybski, Diego and Kropp, J{\"u}rgen}, title = {Effects of changing population or density on urban carbon dioxide emissions}, series = {Nature Communications}, volume = {10}, journal = {Nature Communications}, publisher = {Nature Publ. Group}, address = {London}, issn = {2041-1723}, doi = {10.1038/s41467-019-11184-y}, pages = {9}, year = {2019}, abstract = {The question of whether urbanization contributes to increasing carbon dioxide emissions has been mainly investigated via scaling relationships with population or population density. However, these approaches overlook the correlations between population and area, and ignore possible interactions between these quantities. Here, we propose a generalized framework that simultaneously considers the effects of population and area along with possible interactions between these urban metrics. Our results significantly improve the description of emissions and reveal the coupled role between population and density on emissions. These models show that variations in emissions associated with proportionate changes in population or density may not only depend on the magnitude of these changes but also on the initial values of these quantities. For US areas, the larger the city, the higher is the impact of changing its population or density on its emissions; but population changes always have a greater effect on emissions than population density.}, language = {en} } @article{GudipudiRybskiLuedekeetal.2018, author = {Gudipudi, Venkata Ramana and Rybski, Diego and L{\"u}deke, Matthias K. B. and Zhou, Bin and Liu, Zhu and Kropp, J{\"u}rgen}, title = {The efficient, the intensive, and the productive}, series = {Applied Energy}, volume = {236}, journal = {Applied Energy}, publisher = {Elsevier}, address = {Oxford}, issn = {0306-2619}, doi = {10.1016/j.apenergy.2018.11.054}, pages = {155 -- 162}, year = {2018}, abstract = {Urban areas play an unprecedented role in potentially mitigating climate change and supporting sustainable development. In light of the rapid urbanisation in many parts on the globe, it is crucial to understand the relationship between settlement size and CO2 emission efficiency of cities. Recent literature on urban scaling properties of emissions as a function of population size has led to contradictory results and more importantly, lacked an in-depth investigation of the essential factors and causes explaining such scaling properties. Therefore, in analogy to the well-established Kaya Identity, we develop a relation combining the involved exponents. We demonstrate that application of this Urban Kaya Relation will enable a comprehensive understanding about the intrinsic factors determining emission efficiencies in large cities by applying it to a global dataset of 61 cities. Contrary to traditional urban scaling studies which use Ordinary Least Squares (OLS) regression, we show that the Reduced Major Axis (RMA) is necessary when complex relations among scaling exponents are to be investigated. RMA is given by the geometric mean of the two OLS slopes obtained by interchanging the dependent and independent variable. We discuss the potential of the Urban Kaya Relation in mainstreaming local actions for climate change mitigation.}, language = {en} } @article{GudipudiLuedekeRybskietal.2018, author = {Gudipudi, Ramana Venkata and L{\"u}deke, Matthias K. B. and Rybski, Diego and Kropp, J{\"u}rgen}, title = {Benchmarking urban eco-efficiency and urbanites' perception}, series = {Cities}, volume = {74}, journal = {Cities}, publisher = {Elsevier}, address = {Oxford}, issn = {0264-2751}, doi = {10.1016/j.cities.2017.11.009}, pages = {109 -- 118}, year = {2018}, abstract = {Urbanization as an inexorable global trend stresses the need to identify cities which are eco-efficient. These cities enable socioeconomic development with lower environmental burden, both being multidimensional concepts. Based on this approach, we benchmark 88 European cities using (i) an advanced version of regression residual ranking and (ii) Data Envelopment Analysis (DEA). Our results show that Stockholm, Munich and Oslo perform well irrespective of the benchmarking method. Furthermore, our results indicate that larger European cities are eco-efficient given the socioeconomic benefits they offer compared to smaller cities. In addition, we analyze correlations between a subjective public perception ranking and our objective eco-efficiency rankings for a subset of 45 cities. This exercise revealed three insights: (1) public perception about quality of life in a city is not merely confined to the socioeconomic well-being but rather to its combination with a lower environmental burden; (2) public perception correlates well with both formal ranking outcomes, corroborating the choice of variables; and (3) the advanced regression residual method appears to be more adequate to fit the urbanites' perception ranking (correlation coefficient about 0.6). This can be interpreted as an indication that urbanites' perception reflects the typical eco-efficiency performance and is less influenced by exceptionally performing cities (in the latter case, DEA should have better correlation coefficient). This study highlights that the socioeconomic growth in cities should not be environmentally detrimental as this might lead to significant discontent regarding perceived quality of urban life.}, language = {en} }