@article{WengLuedekeZempetal.2018, author = {Weng, Wei and L{\"u}deke, Matthias K. B. and Zemp, Delphine Clara and Lakes, Tobia and Kropp, J{\"u}rgen}, title = {Aerial and surface rivers}, series = {Hydrology and earth system sciences : HESS}, volume = {22}, journal = {Hydrology and earth system sciences : HESS}, number = {1}, publisher = {Copernicus}, address = {G{\"o}ttingen}, issn = {1027-5606}, doi = {10.5194/hess-22-911-2018}, pages = {911 -- 927}, year = {2018}, abstract = {The abundant evapotranspiration provided by the Amazon forests is an important component of the hydrological cycle, both regionally and globally. Since the last century, deforestation and expanding agricultural activities have been changing the ecosystem and its provision of moisture to the atmosphere. However, it remains uncertain how the ongoing land use change will influence rainfall, runoff, and water availability as findings from previous studies differ. Using moisture tracking experiments based on observational data, we provide a spatially detailed analysis recognizing potential teleconnection between source and sink regions of atmospheric moisture. We apply land use scenarios in upwind moisture sources and quantify the corresponding rainfall and runoff changes in downwind moisture sinks. We find spatially varying responses of water regimes to land use changes, which may explain the diverse results from previous studies. Parts of the Peruvian Amazon and western Bolivia are identified as the sink areas most sensitive to land use change in the Amazon and we highlight the current water stress by Amazonian land use change on these areas in terms of the water availability. Furthermore, we also identify the influential source areas where land use change may considerably reduce a given target sink's water reception (from our example of the Ucayali River basin outlet, rainfall by 5-12 \% and runoff by 19-50 \% according to scenarios). Sensitive sinks and influential sources are therefore suggested as hotspots for achieving sustainable land-water management.}, 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} } @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} }