Impacts of climate and land use changes on water variability, using a Budyko framework: case study in Gansu, China

Author(s):  
Qing He ◽  
Kwok Pan Chun ◽  
Omer Yetemen ◽  
Bastien Dieppois ◽  
Liang Chen ◽  
...  

<p>Disentangling the effects of climate and land use changes on regional hydrological conditions is critical for local water and food security. The water variability over climate transition regions at the midlatitudes is sensitive to changes in regional climate and land use. Gansu, located in northwest China, is a midlatitude climate transition region with sharp climate and vegetation gradients. In this study, the effects of climate and land‑use changes on water balances are investigated over Gansu between 1981 and 2015 using a Budyko framework. Results show that there is reduced runoff generation potential over Gansu during 1981 and 2015, especially in the southern part of the region. Based on statistical scaling relationships, local runoff generation potential over Gansu are related to the El Nino-Southern Oscillation (ENSO). Intensified El Nino conditions weaken the Asian monsoons, leading to precipitation deficits over Gansu. Moreover, the regional evapotranspiration (ET) is increasing due to the warming temperature. The decreasing precipitation and increasing ET cause the decline of runoff generation potential over Gansu. Using the dynamical downscaling model outputs, the Budyko analysis indicates that increasing coverage of forests and croplands may lead to higher ET and may reduce runoff generation potential over Gansu. Moreover, the contributions of climate variability and land‑use changes vary spatially. In the southwest part of Gansu, the impacts of climate variability on water variations are larger (around 80%) than that of land‑use changes (around 20%), while land use changes are the dominant drivers of water variability in the southeast part of the region. The decline of runoff generation potential reveals a potential risk for local water and food security over Gansu. The water‑resource assessment approach developed in this study is applicable for collaborative planning at other climate transition regions at the midlatitudes with complex climate and land types for the Belt and Road Initiative.</p>

2020 ◽  
Author(s):  
Qing He ◽  
Kwok Pan Chun ◽  
Xicai Pan ◽  
Liang Chen ◽  
Pinyu Fan

<p>Vegetation is an integrated regional indicator of environmental changes related to soil, water and climate. For investigating climate change impacts on ecosystems, the transition zones of vegetations are natural hotspots of historical variations. As a transition zone between humid and arid climates in the northwest region of China, the terrestrial ecosystems of Gansu vary from dense vegetation landscapes in southeast to deserts in northwest. Exploring spatiotemporal vegetation responses to climate variations over Gansu has a great significance to project shifting northwest China vegetation patterns which affect regional water and food security. In this study, the spatiotemporal variations of vegetation were characterised by using the Normalized Difference Vegetation Index (NDVI). Between 2001 and 2019, there was a significant increase of the vegetation cover in almost the whole Gansu, and the increasing trend (around 0.015) was more predominant in the southeast part. Over the whole Gansu, especially at the southeast region, the Webster and Yang Monsoon (WYM) and the North Pacific El Nino oscillation (NP) had significant positive relationships with the extent of vegetation coverage at intra-annual and decadal scales respectively. Although the Central Pacific El Nino oscillation (CP) is only a statistically significant variable for some spotty locations of Gansu, it is negatively related to the vegetation variation over the northwest Gansu at an interannual scale. Based on the above relationships between vegetation and climate variables at different temporal scales, the future vegetation conditions of Gansu were projected based on the Beijing Normal University Earth System Model (BNU-ESM) outputs for the RCP4.5 and RCP8.5 scenarios. In a short term (the 2020s), vegetations in Gansu would increase because of the warmer temperatures along with possible increasing snowmelt water. However, for longer terms (the 2050s and the 2080s), the regional vegetation would significantly decline for both RCP4.5 and RCP8.5 scenarios, due to the depletion of snowmelt water sources resulted from the continuously increasing temperature and less snow accumulation in the region. The vegetation projections revealed the future desertification risk in Gansu. These results have important implications to water and food security in the vegetation transition zones of northwest China, which is a key region of the One Belt One Road initiative, connecting semi-arid regions of central Asian nations.</p>


2013 ◽  
Vol 5 (2) ◽  
pp. 724-748 ◽  
Author(s):  
Jawad Al-Bakri ◽  
Mohammad Salahat ◽  
Ayman Suleiman ◽  
Marwan Suifan ◽  
Mohammad Hamdan ◽  
...  

2005 ◽  
Vol 360 (1463) ◽  
pp. 2169-2182 ◽  
Author(s):  
Menghestab Haile

Although considerable achievements in the global reduction of hunger and poverty have been made, progress in Africa so far has been very limited. At present, a third of the African population faces widespread hunger and chronic malnutrition and is exposed to a constant threat of acute food crisis and famine. The most affected are rural households whose livelihood is heavily dependent on traditional rainfed agriculture. Rainfall plays a major role in determining agricultural production and hence the economic and social well being of rural communities. The rainfall pattern in sub-Saharan Africa is influenced by large-scale intra-seasonal and inter-annual climate variability including occasional El Niño events in the tropical Pacific resulting in frequent extreme weather event such as droughts and floods that reduce agricultural outputs resulting in severe food shortages. Households and communities facing acute food shortages are forced to adopt coping strategies to meet the immediate food requirements of their families. These extreme responses may have adverse long-term impacts on households' ability to have sustainable access to food as well as the environment. The HIV/AIDS crisis has also had adverse impacts on food production activities on the continent. In the absence of safety nets and appropriate financial support mechanisms, humanitarian aid is required to enable households effectively cope with emergencies and manage their limited resources more efficiently. Timely and appropriate humanitarian aid will provide households with opportunities to engage in productive and sustainable livelihood strategies. Investments in poverty reduction efforts would have better impact if complemented with timely and predictable response mechanisms that would ensure the protection of livelihoods during crisis periods whether weather or conflict-related. With an improved understanding of climate variability including El Niño, the implications of weather patterns for the food security and vulnerability of rural communities have become more predictable and can be monitored effectively. The purpose of this paper is to investigate how current advances in the understanding of climate variability, weather patterns and food security could contribute to improved humanitarian decision-making. The paper will propose new approaches for triggering humanitarian responses to weather-induced food crises.


2012 ◽  
Vol 1 (1) ◽  
Author(s):  
Johnny Chavarría Viteri ◽  
Dennis Tomalá Solano

La variabilidad climática es la norma que ha modulado la vida en el planeta. Este trabajo demuestra que las pesquerías y acuicultura costera ecuatorianas no son la excepción, puesto que tales actividades están fuertemente influenciadas por la variabilidad ENSO (El Niño-Oscilación del Sur) y PDO (Oscilación Decadal del Pacífico), planteándose que la señal del cambio climático debe contribuir a esta influencia. Se destaca también que, en el análisis de los efectos de la variabilidad climática sobre los recursos pesqueros, el esfuerzo extractivo también debe ser considerado. Por su parte, la acción actual de la PDO está afectando la señal del cambio climático, encontrándose actualmente en fases opuestas. Se espera que estas señales entren en fase a finales de esta década, y principalmente durante la década de los 20 y consecuentemente se evidencien con mayor fuerza los efectos del Cambio Climático. Palabras Clave: Variabilidad Climática, Cambio Climático, ENSO, PDO, Pesquerías, Ecuador. ABSTRACT Climate variability is the standard that has modulated life in the planet. This work shows that the Ecuadorian  fisheries and aquaculture are not the exception, since such activities are strongly influenced by ENSO variability (El Niño - Southern Oscillation) and PDO (Pacific Decadal Oscillation), considering that the signal of climate change should contribute to this influence. It also emphasizes that in the analysis of the effects of climate variability on the fishing resources, the extractive effort must also be considered. For its part, the current action of the PDO is affecting the signal of climate change, now found on opposite phases. It is hoped that these signals come into phase at the end of this decade, and especially during the decade of the 20’s and more strongly evidencing the effects of climate change. Keywords: Climate variability, climate change, ENSO (El Niño - Southern Oscillation) and PDO  (Pacific Decadal Oscillation); fisheries, Ecuador. Recibido: mayo, 2012Aprobado: agosto, 2012


Author(s):  
Luoman Pu ◽  
Jiuchun Yang ◽  
Lingxue Yu ◽  
Changsheng Xiong ◽  
Fengqin Yan ◽  
...  

Crop potential yields in cropland are the essential reflection of the utilization of cropland resources. The changes of the quantity, quality, and spatial distribution of cropland will directly affect the crop potential yields, so it is very crucial to simulate future cropland distribution and predict crop potential yields to ensure the future food security. In the present study, the Cellular Automata (CA)-Markov model was employed to simulate land-use changes in Northeast China during 2015–2050. Then, the Global Agro-ecological Zones (GAEZ) model was used to predict maize potential yields in Northeast China in 2050, and the spatio-temporal changes of maize potential yields during 2015–2050 were explored. The results were the following. (1) The woodland and grassland decreased by 5.13 million ha and 1.74 million ha respectively in Northeast China from 2015 to 2050, which were mainly converted into unused land. Most of the dryland was converted to paddy field and built-up land. (2) In 2050, the total maize potential production and average potential yield in Northeast China were 218.09 million tonnes and 6880.59 kg/ha. Thirteen prefecture-level cities had maize potential production of more than 7 million tonnes, and 11 cities had maize potential yields of more than 8000 kg/ha. (3) During 2015–2050, the total maize potential production and average yield decreased by around 23 million tonnes and 700 kg/ha in Northeast China, respectively. (4) The maize potential production increased in 15 cities located in the plain areas over the 35 years. The potential yields increased in only nine cities, which were mainly located in the Sanjiang Plain and the southeastern regions. The results highlight the importance of coping with the future land-use changes actively, maintaining the balance of farmland occupation and compensation, improving the cropland quality, and ensuring food security in Northeast China.


2004 ◽  
Vol 8 (5) ◽  
pp. 903-922 ◽  
Author(s):  
M. Bari ◽  
K. R. J. Smettem

Abstract. A conceptual water balance model is presented to represent changes in monthly water balance following land use changes. Monthly rainfall–runoff, groundwater and soil moisture data from four experimental catchments in Western Australia have been analysed. Two of these catchments, "Ernies" (control, fully forested) and "Lemon" (54% cleared) are in a zone of mean annual rainfall of 725 mm, while "Salmon" (control, fully forested) and "Wights" (100% cleared) are in a zone with mean annual rainfall of 1125 mm. At the Salmon forested control catchment, streamflow comprises surface runoff, base flow and interflow components. In the Wights catchment, cleared of native forest for pasture development, all three components increased, groundwater levels rose significantly and stream zone saturated area increased from 1% to 15% of the catchment area. It took seven years after clearing for the rainfall–runoff generation process to stabilise in 1984. At the Ernies forested control catchment, the permanent groundwater system is 20 m below the stream bed and so does not contribute to streamflow. Following partial clearing of forest in the Lemon catchment, groundwater rose steadily and reached the stream bed by 1987. The streamflow increased in two phases: (i) immediately after clearing due to reduced evapotranspiration, and (ii) through an increase in the groundwater-induced stream zone saturated area after 1987. After analysing all the data available, a conceptual monthly model was created, comprising four inter-connecting stores: (i) an upper zone unsaturated store, (ii) a transient stream zone store, (ii) a lower zone unsaturated store and (iv) a saturated groundwater store. Data such as rooting depth, Leaf Area Index, soil porosity, profile thickness, depth to groundwater, stream length and surface slope were incorporated into the model as a priori defined attributes. The catchment average values for different stores were determined through matching observed and predicted monthly hydrographs. The observed and predicted monthly runoff for all catchments matched well with coefficients of determination (R2) ranging from 0.68 to 0.87. Predictions were relatively poor for: (i) the Ernies catchment (lowest rainfall, forested), and (ii) months with very high flows. Overall, the predicted mean annual streamflow was within ±8% of the observed values. Keywords: monthly streamflow, land use change, conceptual model, data-based approach, groundwater


2017 ◽  
Vol 10 (5) ◽  
pp. 268
Author(s):  
Olivia Muza

El-Nino Southern Oscillation (ENSO) is the most recurrent change in climate impacting agriculture productivity and food security. This study investigates ENSO impacts on four cereal crops (maize, millet, sorghum and wheat) using crop production and climate datasets spanning the years 1960-2015. The results of this study reveal that during El Nino (La Nina) maize, sorghum and wheat production decreases (increases) while that of millet increases (decreases). Even though, the correlation is statistically significant for maize only, the outcome is a call to review the macro-food policy taking into account ENSO-related phase effects to redress food insecurity. The study recommends incentives for agricultural productivity including irrigation intensification and small grain value chain development, trade and food security arrangements, income generation opportunities and strategic partnerships for improved food and nutrition security.


Author(s):  
Farida Afriani Astuti ◽  
Herwin Lukito

Kabupaten Sleman memiliki banyak daya tarik yang memicu terjadinya urbanisasi yang dapat terlihat dari fenomeno perubahan penggunaan lahan . Perubahan penggunaan lahan di Kabupaten Sleman terjadi pada kawasan keamanan dan ketahanan pangan yang terdiri dari Kecamatan Moyudan, Minggir, Sayegan, Godean, Mlati, dan Tempel.  Fenomena perubahan penggunaan lahan penting untuk dikontrol dan dikendalikan karena kawasan tersebut memiliki peran penting bagi ketahanan pangan di Kabupaten Sleman. Metode penelitian yang digunakan adalah metode deskriptif. Di dalam metode deskriptif terdapat metode survey yang digunakaan untuk mengetahui kondisi eksisting penggunaan lahan di daerah penelitian. Sedangkan untuk perubahan penggunaan lahan pada kawasan keamanan dan ketahanan pangan di Kabupaten Sleman dari Tahun 2012 sampai Tahun 2018 diperoleh dengan metode overlay peta penggunaan lahan yang diperoleh dari Citra Quickbird pada tahun tersebut. Perubahan penggunaan lahan pada kawasan keamanan dan ketahanan pangan Kabupaten Sleman mencapai 57,33 km2 atau 33,93% dari luas total daerah penelitian. Perubahan penggunaan lahan didominasi oleh perubahan lahan sawah menjadi hutan produksi seluas 15,05 km2. Faktor pendorong adanya perubahan penggunaan lahan tersebut adalah produktivitas pertanian sawah yang semakin menurun tiap tahunnya.Sleman Regency has many attractions that trigger urbanization which can be seen from the phenomenon of land-use change. This phenomenon occurs in Sleman Regency particularly in the area of food security and sustainability which is spreading in various districts such as Moyudan, Minggir, Sayegan, Godean, Mlati, and Tempel. The phenomenon of land change must be managed and controlled because the areas have an important role for food security in Sleman Regency. The method used for the research is descriptive method. Survey is a part of descriptive method which used to determine the existing conditions of land use in the research object areas. Whereas for land-use changes in the area of food security and sustainability in Sleman Regency from 2012 to 2018 was obtained with the method of land-use map overlay obtained from Quickbird imagery in those years.Land-use change in the area of food security and sustainability of  Sleman Regency reaches 57.33 km2 or 33.93% from the total of research study area. Land-use change is dominated by the diversions of rice fields to forests that reach 15.05 km2. The driving factor for this phenomenon is the decreasing annual productivity of rice field. 


Author(s):  
Cynthia Rosenzweig ◽  
Daniel Hillel

The climate system envelops our planet, with swirling fluxes of mass, momentum, and energy through air, water, and land. Its processes are partly regular and partly chaotic. The regularity of diurnal and seasonal fluctuations in these processes is well understood. Recently, there has been significant progress in understanding some of the mechanisms that induce deviations from that regularity in many parts of the globe. These mechanisms include a set of combined oceanic–atmospheric phenomena with quasi-regular manifestations. The largest of these is centered in the Pacific Ocean and is known as the El Niño–Southern Oscillation. The term “oscillation” refers to a shifting pattern of atmospheric pressure gradients that has distinct manifestations in its alternating phases. In the Arctic and North Atlantic regions, the occurrence of somewhat analogous but less regular interactions known as the Arctic Oscillation and its offshoot, the North Atlantic Oscillation, are also being studied. These and other major oscillations influence climate patterns in many parts of the globe. Examples of other large-scale interactive ocean–atmosphere– land processes are the Pacific Decadal Oscillation, the Madden-Julian Oscillation, the Pacific/North American pattern, the Tropical Atlantic Variability, the West Pacific pattern, the Quasi-Biennial Oscillation, and the Indian Ocean Dipole. In this chapter we review the earth’s climate system in general, define climate variability, and describe the processes related to ENSO and the other major systems and their interactions. We then consider the possible connections of the major climate variability systems to anthropogenic global climate change. The climate system consists of a series of fluxes and transformations of energy (radiation, sensible and latent heat, and momentum), as well as transports and changes in the state of matter (air, water, solid matter, and biota) as conveyed and influenced by the atmosphere, the ocean, and the land masses. Acting like a giant engine, this dynamic system is driven by the infusion, transformation, and redistribution of energy.


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