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- Gordon, Line J., et al.
(författare)
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Human modification of global water vapor flows from the land surface
- 2005
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 102:21, s. 7612-7617
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Tidskriftsartikel (refereegranskat)abstract
- It is well documented that human modification of the hydrological cycle has profoundly affected the flow of liquid water across the Earth’s land surface. Alteration of water vapor flows through land-use changes has received comparatively less attention, despite compelling evidence that such alteration can influence the functioning of the Earth System. We show that deforestation is as large a driving force as irrigation in terms of changes in the hydrological cycle. Deforestation has decreased global vapor flows from land by 4% (3,000 km3/yr), a decrease that is quantitatively as large as the increased vapor flow caused by irrigation (2,600 km3/yr). Although the net change in global vapor flows is close to zero, the spatial distributions of deforestation and irrigation are different, leading to major regional transformations of vapor-flow patterns. We analyze these changes in the light of future land-use-change projections that suggest widespread deforestation in sub-Saharan Africa and intensification of agricultural production in the Asian monsoon region. Furthermore, significant modification of vapor flows in the lands around the Indian Ocean basin will increase the risk for changes in the behavior of the Asian monsoon system. This analysis suggests that the need to increase food production in one region may affect the capability to increase food production in another. At the scale of the Earth as a whole, our results emphasize the need for climate models to take land-use change, in both land cover and irrigation, into account.
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| 4. |
- Rockström, Johan, et al.
(författare)
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A safe operating space for humanity
- 2009
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 461:7263, s. 472-475
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Tidskriftsartikel (refereegranskat)
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- Rockström, Johan, et al.
(författare)
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Linkages among water vapour flows, food production and terrestrial ecosystem services.
- 1999
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Ingår i: Conservation Ecology. - Ottawa : Carleton University for The Resiliance Alliance. - 1195-5449. ; 3:2
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Tidskriftsartikel (refereegranskat)abstract
- Global freshwater assessments have not addressed the linkages among water vapor flows, agricultural food production, and terrestrial ecosystem services. We perform the first bottom-up estimate of continental water vapor flows, subdivided into the major terrestrial biomes, and arrive at a total continental water vapor flow of 70,000 km3/yr (ranging from 56,000 to 84,000 km3/yr). Of this flow, 90% is attributed to forests, including woodlands (40,000 km3/yr), wetlands (1400 km3/yr), grasslands (15,100 km3/yr), and croplands (6800 km3/yr). These terrestrial biomes sustain society with essential welfare-supporting ecosystem services, including food production. By analyzing the freshwater requirements of an increasing demand for food in the year 2025, we discover a critical trade-off between flows of water vapor for food production and for other welfare-supporting ecosystem services. To reduce the risk of unintentional welfare losses, this trade-off must become embedded in intentional ecohydrological landscape management
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| 6. |
- Rockström, Johan, et al.
(författare)
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Planetary Boundaries : Exploring the Safe Operating Space for Humanity
- 2009
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Ingår i: Ecology and Society. - 1708-3087. ; 14:2, s. 32-
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Tidskriftsartikel (refereegranskat)abstract
- Anthropogenic pressures on the Earth System have reached a scale where abrupt global environmental change can no longer be excluded. We propose a new approach to global sustainability in which we define planetary boundaries within which we expect that humanity can operate safely. Transgressing one or more planetary boundaries may be deleterious or even catastrophic due to the risk of crossing thresholds that will trigger non-linear, abrupt environmental change within continental- to planetary-scale systems. We have identified nine planetary boundaries and, drawing upon current scientific understanding, we propose quantifications for seven of them. These seven are climate change (CO2 concentration in the atmosphere <350 ppm and/or a maximum change of +1 W m(-2) in radiative forcing); ocean acidification (mean surface seawater saturation state with respect to aragonite >= 80% of pre-industrial levels); stratospheric ozone (<5% reduction in O-3 concentration from pre-industrial level of 290 Dobson Units); biogeochemical nitrogen (N) cycle (limit industrial and agricultural fixation of N-2 to 35 Tg N yr(-1)) and phosphorus (P) cycle (annual P inflow to oceans not to exceed 10 times the natural background weathering of P); global freshwater use (<4000 km(3) yr(-1) of consumptive use of runoff resources); land system change (<15% of the ice-free land surface under cropland); and the rate at which biological diversity is lost (annual rate of <10 extinctions per million species). The two additional planetary boundaries for which we have not yet been able to determine a boundary level are chemical pollution and atmospheric aerosol loading. We estimate that humanity has already transgressed three planetary boundaries: for climate change, rate of biodiversity loss, and changes to the global nitrogen cycle. Planetary boundaries are interdependent, because transgressing one may both shift the position of other boundaries or cause them to be transgressed. The social impacts of transgressing boundaries will be a function of the social-ecological resilience of the affected societies. Our proposed boundaries are rough, first estimates only, surrounded by large uncertainties and knowledge gaps. Filling these gaps will require major advancements in Earth System and resilience science. The proposed concept of "planetary boundaries" lays the groundwork for shifting our approach to governance and management, away from the essentially sectoral analyses of limits to growth aimed at minimizing negative externalities, toward the estimation of the safe space for human development. Planetary boundaries define, as it were, the boundaries of the "planetary playing field" for humanity if we want to be sure of avoiding major human-induced environmental change on a global scale.
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| 8. |
- Rockström, Johan, et al.
(författare)
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The unfolding water drama in the Anthropocene : towards a resilience-based perspective on water for global sustainability
- 2014
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Ingår i: Ecohydrology. - : Wiley. - 1936-0584 .- 1936-0592. ; 7:5, s. 1249-1261
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Tidskriftsartikel (refereegranskat)abstract
- The human influence on the global hydrological cycle is now the dominant force behind changes in water resources across the world and in regulating the resilience of the Earth system. The rise in human pressures on global freshwater resources is in par with other anthropogenic changes in the Earth system (from climate to ecosystem change), which has prompted science to suggest that humanity has entered a new geological epoch, the Anthropocene. This paper focuses on the critical role of water for resilience of social-ecological systems across scales, by avoiding major regime shifts away from stable environmental conditions, and in safeguarding life-support systems for human wellbeing. It highlights the dramatic increase of water crowding: near-future challenges for global water security and expansion of food production in competition with carbon sequestration and biofuel production. It addresses the human alterations of rainfall stability, due to both land-use changes and climate change, the ongoing overuse of blue water, reflected in river depletion, expanding river basin closure, groundwater overexploitation and water pollution risks. The rising water turbulence in the Anthropocene changes the water research and policy agenda, from a water-resource efficiency to a water resilience focus. This includes integrated land and water stewardship to sustain wetness-dependent ecological functions at the landscape scale and a stronger emphasis on green water management for ecosystem services. A new paradigm of water governance emerges, encouraging land-use practices that explicitly take account of the multifunctional roles of water, with adequate attention to planetary freshwater boundaries and cross-scale interactions.
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| 9. |
- Rockström, Johan, et al.
(författare)
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Water resilience for human prosperity
- 2014
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- The world's human population now constitutes the largest driving force of changes to the biosphere. Emerging water challenges require new ideas for governance and management of water resources in the context of rapid global change. This book presents a new approach to water resources, addressing global sustainability and focusing on socio-ecological resilience to changes. Topics covered include the risks of unexpected change, human impacts and dependence on global water, the prospects for feeding the world's population by 2050, and a pathway for the future. The book's innovative and integrated approach links green and blue freshwater with terrestrial and aquatic ecosystem functions and use. It also links changes arising from land-use alteration with the impacts of those changes on social-ecological systems and ecosystem services. This is an important, state-of-the-art resource for academic researchers and water resource professionals, and a key reference for graduate students studying water resource governance and management.
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