@article{CramerBondeauSchaphoffetal.2004, author = {Cramer, Wolfgang and Bondeau, Alberte and Schaphoff, Sibyll and Lucht, Wolfgang and Smith, Benjamin and Sitch, Stephan}, title = {Tropical forests and the global carbon cycle : impacts of atmospheric carbon dioxide, climate change and rate of deforestation}, issn = {0962-8436}, year = {2004}, abstract = {The remaining carbon stocks in wet tropical forests are currently at risk because of anthropogenic deforestation, but also because of the possibility of release driven by climate change. To identify the relative roles of CO2 increase, changing temperature and rainfall, and deforestation in the future, and the magnitude of their impact on atmospheric CO2 concentrations, we have applied a dynamic global vegetation model, using multiple scenarios of tropical deforestation (extrapolated from two estimates of current rates) and multiple scenarios of changing climate (derived from four independent offline general circulation model simulations). Results show that deforestation will probably produce large losses of carbon, despite the uncertainty about the deforestation rates. Some climate models produce additional large fluxes due to increased drought stress caused by rising temperature and decreasing rainfall. One climate model, however, produces an additional carbon sink. Taken together, our estimates of additional carbon emissions during the twenty-first century, for all climate and deforestation scenarios, range from 101 to 367 Gt C, resulting in CO2 concentration increases above background values between 29 and 129 p.p.m. An evaluation of the method indicates that better estimates of tropical carbon sources and sinks require improved assessments of current and future deforestation, and more consistent precipitation scenarios from climate models. Notwithstanding the uncertainties, continued tropical deforestation will most certainly play a very large role in the build-up of future greenhouse gas concentrations}, language = {en} } @article{RockstroemKotzeMilutinovićetal.2024, author = {Rockstr{\"o}m, Johan and Kotz{\´e}, Louis and Milutinović, Svetlana and Biermann, Frank and Brovkin, Victor and Donges, Jonathan and Ebbesson, Jonas and French, Duncan and Gupta, Joyeeta and Kim, Rakhyun and Lenton, Timothy and Lenzi, Dominic and Nakicenovic, Nebojsa and Neumann, Barbara and Schuppert, Fabian and Winkelmann, Ricarda and Bosselmann, Klaus and Folke, Carl and Lucht, Wolfgang and Schlosberg, David and Richardson, Katherine and Steffen, Will}, title = {The planetary commons}, series = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {121}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, number = {5}, publisher = {National Academy of Sciences}, address = {Washington, DC}, issn = {1091-6490}, doi = {10.1073/pnas.2301531121}, pages = {10}, year = {2024}, abstract = {The Anthropocene signifies the start of a no- analogue tra­jectory of the Earth system that is fundamentally different from the Holocene. This new trajectory is characterized by rising risks of triggering irreversible and unmanageable shifts in Earth system functioning. We urgently need a new global approach to safeguard critical Earth system regulating functions more effectively and comprehensively. The global commons framework is the closest example of an existing approach with the aim of governing biophysical systems on Earth upon which the world collectively depends. Derived during stable Holocene conditions, the global commons framework must now evolve in the light of new Anthropocene dynamics. This requires a fundamental shift from a focus only on governing shared resources beyond national jurisdiction, to one that secures critical functions of the Earth system irrespective of national boundaries. We propose a new framework—the planetary commons—which differs from the global commons frame­work by including not only globally shared geographic regions but also critical biophysical systems that regulate the resilience and state, and therefore livability, on Earth. The new planetary commons should articulate and create comprehensive stewardship obligations through Earth system governance aimed at restoring and strengthening planetary resilience and justice.}, language = {en} } @article{FaderGertenThammeretal.2011, author = {Fader, Marianelle and Gerten, Dieter and Thammer, M. and Heinke, J. and Lotze-Campen, Hermann and Lucht, Wolfgang and Cramer, Wolfgang}, title = {Internal and external green-blue agricultural water footprints of nations, and related water and land savings through trade}, series = {Hydrology and earth system sciences : HESS}, volume = {15}, journal = {Hydrology and earth system sciences : HESS}, number = {5}, publisher = {Copernicus}, address = {G{\"o}ttingen}, issn = {1027-5606}, doi = {10.5194/hess-15-1641-2011}, pages = {1641 -- 1660}, year = {2011}, abstract = {The need to increase food production for a growing world population makes an assessment of global agricultural water productivities and virtual water flows important. Using the hydrology and agro-biosphere model LPJmL, we quantify at 0.5 degrees resolution the amount of blue and green water (irrigation and precipitation water) needed to produce one unit of crop yield, for 11 of the world's major crop types. Based on these, we also quantify the agricultural water footprints (WFP) of all countries, for the period 1998-2002, distinguishing internal and external WFP (virtual water imported from other countries) and their blue and green components, respectively. Moreover, we calculate water savings and losses, and for the first time also land savings and losses, through international trade with these products. The consistent separation of blue and green water flows and footprints shows that green water globally dominates both the internal and external WFP (84\% of the global WFP and 94\% of the external WFP rely on green water). While no country ranks among the top ten with respect to all water footprints calculated here, Pakistan and Iran demonstrate high absolute and per capita blue WFP, and the US and India demonstrate high absolute green and blue WFPs. The external WFPs are relatively small (6\% of the total global blue WFP, 16\% of the total global green WFP). Nevertheless, current trade of the products considered here saves significant water volumes and land areas (similar to 263 km(3) and similar to 41 Mha, respectively, equivalent to 5\% of the sowing area of the considered crops and 3.5\% of the annual precipitation on this area). Relating the proportions of external to internal blue/green WFP to the per capita WFPs allows recognizing that only a few countries consume more water from abroad than from their own territory and have at the same time above-average WFPs. Thus, countries with high per capita water consumption affect mainly the water availability in their own country. Finally, this study finds that flows/savings of both virtual water and virtual land need to be analysed together, since they are intrinsically related.}, language = {en} } @article{GertenHoffBondeauetal.2005, author = {Gerten, Dieter and Hoff, Holger and Bondeau, Alberte and Lucht, Wolfgang and Smith, Pascalle and Zaehle, S{\"o}nke}, title = {Contemporary "green" water flows : simulations with a dynamic global vegetation and water balance model}, issn = {1474-7065}, year = {2005}, abstract = {"Green water"-the water stored in the soil and productively used for plant transpiration-is an important quantity particularly in rainfed agriculture (in contrast to "blue water" available in streams and lakes, on which irrigation relies). This study provides preliminary estimates of contemporary (1961-1990) global green water flows (i.e. plant transpiration), using a well-established, process-based dynamic global vegetation and water balance model, LPJ. Transpiration is analysed with respect to differences between a simulation that accounts for human land cover changes and a simulation under conditions of potential natural vegetation. We found that historic land cover change usually reduced the green water flow to the atmosphere, resulting in a global decrease of similar to 7\% in total. To further explore how the biophysical setting influences the green water flow, we analyse the ratio between soil moisture-limited canopy conductance of carbon and water and energy-controlled potential conductance. This plant physiology-based ratio measures the degree to which actual green water flow falls below the potential flow that would occur when the soil is saturated, thus it represents a measure of the water limitation of terrestrial vegetation. We found that plant water limitation is lowest in the wet tropics and at high latitudes, where soil moisture is high enough to meet the atmospheric demand for transpiration. The present results are preliminary, since irrigation is not yet accounted for, and because the model simulations are compromised primarily by the quality of the input data. A more comprehensive and consistent assessment of global green and blue water flows and limitations using an enhanced LPJ model is identified as a prime task for future studies. (c) 2005 Elsevier Ltd. All rights reserved}, 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} }