Environmental change and water management in the Pyrenees: Facts and future perspectives for Mediterranean mountains

This paper analyses the effect of environmental changes observed in the 20th century on hydrology and water management in the southern Pyrenees, in terms of land use and climate. Moreover, a projected water-resource scenario for the 21st century is presented and discussed. Our results demonstrate that changes in precipitation, temperature, and snow accumulation, together with an increase in vegetation density in headwater regions, have led to a marked reduction in water availability in the region. Water resource managers have introduced major changes to dam operations to meet increasing water demand for irrigation purposes in lowland areas. Climatic and land-cover scenarios for the next century indicate that the sustainability of the equilibrium between available resources and water demand will be seriously threatened. These changes predicted for the Pyrenees may be representative of the changes that will occur within many other Mediterranean mountain sectors with similar climatic and socio-economic conditions.     

Impacts of agriculture and urbanization on the climate of the Northeastern United States

The climate sensitivity to specification of agricultural and urban land cover was investigated using the climate version of the Pennsylvania State University/National Center for Atmospheric Research Mesoscale Model (MM5) for 1990 over northeastern United States. The simulations were for 5 yr at a spatial resolution of 36 km. Urbanization resulted in near-surface temperature increases of more than 1 K over the urban sites during both winter and summer. The increase in summer temperature due to urbanization was more widespread than that due to the effect of agricultural land use. The conversion of forest to agricultural land resulted in a decrease in temperature of more than 0.5 K during winter and an increase of more than 1 K during summer over the sites of perturbation. The reduced temperature during winter is related to snow cover. Agricultural lands are covered by snow while the trees in non-agricultural areas protrude through the snow, reducing the albedo of the surface. The warming during summer reflects reduced evaporation. Urbanization also reduces the diurnal temperature range (DTR) by about 0.4 K.     

Geo-informational simulation of possible changes in Central Asian water resources

This study simulates water resources in the Tien Shan alpine basins to forecast how global and regional climate changes would affect river runoff. The model employed annual mean values for the major characteristics of the water cycle: annual air temperature, precipitation, evapotranspiration and river runoff. The simulation was based on 304 hydro-meteorological stations, 23 precipitation sites, 328 high altitudinal points with glaciological measurements, 123 stream-gauges, and 54 evaporation sites, and it took into account topography. The findings were simulated over Tien Shan relief using a 1:500,000 scale 100 m grid resolution Digital Elevation Model. An applicable GIS-based distributed River Runoff Model was implemented in regional conditions and tested in the Tien Shan basins. The annual evapotranspiration exceeds the river runoff in the Tien Shan watersheds particularly up to 3700 m. Hypothetical climate-change scenarios in the Tien Shan predict that by 2100 river runoff will increase by 1.047 times with an increase in air temperature averaging 3 °C and an increase in precipitation averaging 1.2 times the current levels. Change in precipitation, rather than temperature, is the main parameter determining river runoff in the Tien Shan. The maximum ratio for predicted river runoff could reach up to 2.2 and the minimum is predicted to be 0.55 times current levels. This possibly dramatic change in river runoff indicates on non-linear system response caused mainly by the non-linear response of evapotranspiration from air temperature and precipitation changes. In the frame of forecasted possible climate change scenarios the probability of river runoff growth amounts 83–87% and probability of this decline is 17–13% by 2100 in the Tien Shan River basins.     

Effects of anthropogenic intervention in the land hydrologic cycle on global sea level rise

Recent studies suggest that anthropogenic modification of land hydrology (e.g. through groundwater mining, dam building, irrigation, deforestation, wetlands drainage, and urbanization) could significantly impact sea-level rise, although the magnitude and sign of this effect have been widely debated. This paper attempts a comprehensive overview of the effects of human activities on land hydrology. Estimates are provided for the volumes of water associated with each of the major anthropogenic processes and the corresponding equivalent in sea level.Groundwater mining; and runoff from paved and built-up areas are two major sources of water added to the ocean. In contrast, storage of water behind dams, losses through percolation, and evapotranspiration from irrigated fields withhold water that would otherwise flow to the sea. The net effect of these processes holds back the equivalent of 0.8 +- 0.4 mm/yr from sea-level rise. This is a magnitude comparable to, but in the opposite direction from the currently observed sea-level rise of 1–2 mm/yr. These estimates are still preliminary, awaiting better documentation. Coupling of improved land hydrology models with GCMs will help in analysis of feedbacks, especially the partitioning of water among runoff, infiltration, and evaporation.     

A spatially explicit assessment of current and future hotspots of hunger in Sub-Saharan Africa in the context of global change

Hunger knows no boundaries or borders. While much research has focused on undernutrition on a national scale, this report evaluates it at subnational levels for Sub-Saharan Africa (SSA) to pinpoint hotspots where the greatest challenges exist. Undernutrition is assessed with a spatial resolution of 30 arc-minutes by investigating anthropometric data on weight and length of individuals. The impact of climate change on production of six major crops (cassava, maize, wheat, sorghum, rice and millet) is analyzed with a GIS-based Environmental Policy Integrated Climate (GEPIC) model with the same spatial resolution. Future hotspots of hunger are projected in the context of the anticipated climate, social, economic, and bio-physical changes. The results show that some regions in northern and southwestern Nigeria, Sudan and Angola with a currently high number of people with undernutrition might be able to improve their food security situation mainly through increasing purchasing power. In the near future, regions located in Ethiopia, Uganda, Rwanda and Burundi, southwestern Niger, and Madagascar are likely to remain hotspots of food insecurity, while regions located in Tanzania, Mozambique and the Democratic Republic of Congo might face more serious undernutrition. It is likely that both the groups of regions will suffer from lower capacity of importing food as well as lower per capita calorie availability, while the latter group will probably have sharper reduction in per capita calorie availability. Special attention must be paid to the hotspot areas in order to meet the hunger alleviation goals in SSA.     

Modelling the impacts of environmental changes on hydrological regimes in the Hei River Watershed, China

This study aimed to disclose impacts of environment changes on hydrologic regimes in the Hei River Watershed, Shaanxi Province in China. We investigated the effects of the man-made landscape (Jingpen Reservoir) on the rainstorm–flood processes using a proposed Kinematic Wave model, simulated impacts of land use and cover changes on surface runoff generation and river flow characteristics at monthly, seasonal, and annual scales through designed scenarios of different combinations of land use and cover and climate conditions on basis of the SWAT model, evaluated the climate change and human activities effects on water balance from 1954 to 2001. Through these investigations, the following results were achieved. Firstly, it showed that the man-made landscape (the Jingpen Reservoir) had altered the rainstorm–flood process, the flood wave damped right after it flowed out the Jingpen Reservoir. Secondly, changes of land use and cover led to river flow redistribution, soil moisture and recharge fluctuations. Evapotranspiration increased 12.9%, river flow discharge decreased 17.7%, runoff generation process accelerated 1.31 times in 2000 than in 1986, and water resources of the total watershed decreased 7.7% in 2000 compared to the land use and cover scenario in 1986. Finally, the interaction between climate change and human activities led to the total water resource decreased by 10.6% in 2000 compared to that in 1986 in the Hei River Watershed.     

Simulations of water resource environmental changes in China during the last 20 000 years by a regional climate model

We utilize a regional climate model with detailed land surface processes (RegCM2) to simulate East Asian monsoon climates at 0 ka, 6 ka and 21 ka BP, and evaluate the changes in hydrology process, including vapor transportation, precipitation, evapotranspiration and runoff in the eastern and western China during these periods. Results indicate that the Tibetan Plateau climate presents a wet–cold status during the LGM while it exhibits a wet–warm climate at 6 ka BP. The LGM wetter climate over the Tibetan Plateau mainly results from the increased vapor inflow through its south boundary, while the increase in the vapor import over the Tibetan Plateau at 6 ka BP mostly sources from its west boundary. The increase in the LGM runoff over the Tibetan Plateau is mainly caused by the decrease in evapotranspiration, while the increase in runoff at the 6 ka BP mainly by the enhanced precipitation. Eastern China (including southern China) presents a dry status during the LGM, which precipitation and runoff decreases significantly due largely to weakened Asian summer monsoon that results in the decreased vapor inflow through the south boundary of eastern China. The variation pattern in the hydrological cycle in eastern China is contrary to that in western China during the LGM. The increase in precipitation and runoff at 6 ka BP in eastern China is tightly related to the strong Asian summer monsoon that leads to increased vapor import through the south boundary. Long term decrease trend in precipitation and runoff in northern China since the last 20 000 years may be attributed to the steady increase in vapor export through the east boundary as a result of the changes of East Asian monsoon and the adjustments of local atmospheric circulations in this area.     

An ecological economics framework for assessing environmental flows: the case of inter-basin water transfers in Lesotho

This paper used the Lesotho Highlands Water Project (LHWP) that transfers water from the Orange River Basin in Lesotho to the Vaal River Basin in South Africa as a case study to show how environmental sustainability aspects can be integrated into economic development planning. Using the Ecological Social Accounting Matrix (ESAM) for Lesotho that integrates ecological implications of the LHWP with economic benefits of the project, the paper analysed the impact of lost ecological services downstream the LHWP dams in Lesotho on the well-being of households directly affected by the project (riparians) and the general economy of the country. The results revealed that despite significant economic benefits, the project has unintended impacts on ecological resources and services with resultant deleterious well-being implications for riparians. The results from the ESAM analysis indicated that not only the income of riparians is likely to suffer, but also that of other households and social groups, as well as the general economy of Lesotho. While results of the ESAM analysis did not indicate large income impacts on the economy at large, they were significant for riparians. The importance of integrating ecological consequences into impact assessment of IBWT before such transfers can be implemented to ensure sustainable development and considering economy-wide impacts associated with IBWT was proven necessary for a holistic impact assessment of IBWT.     

The economic impact of climate change on Kenyan crop agriculture: A Ricardian approach

This paper measures the economic impact of climate on crops in Kenya. We use cross-sectional data on climate, hydrological, soil and household level data for a sample of 816 households. We estimate a seasonal Ricardian model to assess the impact of climate on net crop revenue per acre. The results show that climate affects crop productivity. There is a non-linear relationship between temperature and revenue on one hand and between precipitation and revenue on the other. Estimated marginal impacts suggest that global warming is harmful for crop productivity. Predictions from global circulation models confirm that global warming will have a substantial impact on net crop revenue in Kenya. The results also show that the temperature component of global warming is much more important than precipitation. Findings call for monitoring of climate change and dissemination of information to farmers to encourage adaptations to climate change. Improved management and conservation of available water resources, water harvesting and recycling of wastewater could generate water for irrigation purposes especially in the arid and semi-arid areas.     

Evidence for Amazonian acidic liquid water on Mars—A reinterpretation of MER mission results

The Mars Exploration Rover (MER) missions have confirmed aqueous activity on Mars. Here we review the analyses of the field-based MER data, and conclude that some weathering processes in Meridiani Planum and Gusev crater are better explained by late diagenetic water-rock interactions than by early diagenesis only. At Meridiani, the discovery of jarosite by MER-1 Opportunity indicates acidic aqueous activity, evaporation, and desiccation of rock materials. MER-based information, placed into the context of published data, point to local and limited aqueous activity during geologically recent times in Meridiani. Pre-Amazonian environmental changes (including important variations in the near-surface groundwater reservoirs, impact cratering, and global dust storms and other pervasive wind-related erosion) are too extreme for pulverulent jarosite to survive over extended time periods, and therefore we argue instead that jarosite deposits must have formed in a climatically more stable period. Any deposits of pre-existent concretionary jarosite surviving up to the Amazonian would not have reached completion in the highly saline and acidic brines occurring at Meridiani. MER-2 Spirit has also revealed evidence for local and limited Amazonian aqueous environmental conditions in Gusev crater, including chemical weathering leading to goethite and hematite precipitation, rock layering, and chemical enhancement of Cl, S, Br, and oxidized iron in rocks and soils. The estimated relative age of the impact crater materials in Gusev indicates that these processes have taken place during the last 2 billion years. We conclude that minor amounts of shallow acidic liquid water have been present on the surface of Mars at local scales during the Amazonian Period.