643 research outputs found

    Energy-Water Balance and Ecosystem Response to Climate Change in Southwest China

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    It is important to highlight energy-water balance and ecosystem response to climate changes. The change of water-energy balance and ecosystem due to climate change will affect the regional ecological and human living significantly, especially in Southwest China which is an ecologically fragile area. This chapter presents the retrieval methodology of parameters (reconstruction of vegetation index, land cover semi-automatic classification, a time series reconstruction of land surface temperature based on Kalman filter and precipitation interpolation based on thin plate smoothing splines), time-series analysis methodology (land cover change, vegetation succession and drought index) and correlate analysis methodology (correlation coefficient and principal component analysis). Then, based on the above method, remote sensing data were integrated, a time series analysis on a 30-year data was used to illustrate the water-energy balance and ecosystem variability in Southwest China. The result showed that energy-water balance and ecosystem (ecosystem structures, vegetation and droughts) have severe response to climate change

    Large Chinese land carbon sink estimated from atmospheric carbon dioxide data

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    Limiting the rise in global mean temperatures relies on reducing carbon dioxide (CO2) emissions and on the removal of CO2 by land carbon sinks. China is currently the single largest emitter of CO2, responsible for approximately 27 per cent (2.67 petagrams of carbon per year) of global fossil fuel emissions in 20171. Understanding of Chinese land biosphere fluxes has been hampered by sparse data coverage2–4, which has resulted in a wide range of a posteriori estimates of flux. Here we present recently available data on the atmospheric mole fraction of CO2, measured from six sites across China during 2009 to 2016. Using these data, we estimate a mean Chinese land biosphere sink of −1.11 ± 0.38 petagrams of carbon per year during 2010 to 2016, equivalent to about 45 per cent of our estimate of annual Chinese anthropogenic emissions over that period. Our estimate reflects a previously underestimated land carbon sink over southwest China (Yunnan, Guizhou and Guangxi provinces) throughout the year, and over northeast China (especially Heilongjiang and Jilin provinces) during summer months. These provinces have established a pattern of rapid afforestation of progressively larger regions5,6, with provincial forest areas increasing by between 0.04 million and 0.44 million hectares per year over the past 10 to 15 years. These large-scale changes reflect the expansion of fast-growing plantation forests that contribute to timber exports and the domestic production of paper7. Space-borne observations of vegetation greenness show a large increase with time over this study period, supporting the timing and increase in the land carbon sink over these afforestation regions

    Quantifying Replenish Benefits in Community Water Partnership Projects, Final Report for 2012

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    The Coca-Cola Company is quantifying the water-related "Replenish" benefits derived through its Community Water Partnership (CWP) projects. The work described in this report builds on previous efforts, and provides a current status of quantification results for three categories of CWP projects: Watershed Protection; Water for Productive Use; and Water Access and Sanitation.This report was prepared for the Coca-Cola Company in collaboration with the Nature Conservancy, by LimnoTech

    Vegetation Dynamics Revealed by Remote Sensing and Its Feedback to Regional and Global Climate

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    This book focuses on some significant progress in vegetation dynamics and their response to climate change revealed by remote sensing data. The development of satellite remote sensing and its derived products offer fantastic opportunities to investigate vegetation changes and their feedback to regional and global climate systems. Special attention is given in the book to vegetation changes and their drivers, the effects of extreme climate events on vegetation, land surface albedo associated with vegetation changes, plant fingerprints, and vegetation dynamics in climate modeling

    The impact of agricultural irrigation on land surface characteristics and near surface climate in China

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    It is well known that land cover and land use change can significantly influence the climate system by modulating surface-atmosphere exchanges. Land management, such as irrigation, also has a profound influence on the climate system. Irrigation can alter the water and energy flux from ground surface to the atmosphere and further influence near surface climate. Considering its dramatic expansion during the last century, the widespread use of irrigation has had an ongoing impact on our climate system. However, until now, this relationship between increased irrigation and its effect on climate system has not been well examined. The main objective of this dissertation is to quantify the irrigation impacts on land surface characteristics and near surface climate over China by using both observational (remote sensing and meteorological observation) and modeling studies with four specific questions: Where are the irrigated areas in China? What might have happened in the past? What will happen as a result of irrigation expansion in the future? And what is the relationship between the land cover land use change (LCLUC) impact and the irrigation impact on near surface climate in China? To answer these questions, I 1) developed three irrigation potential indices and produced a high resolution irrigation map of China; 2)analyzed and compared meteorological and remote sensing observations in irrigated and non-irrigated agriculture areas of China; 3) simulated both irrigation and LCLUC impact on land surface energy balance components (i.e., land surface temperature, latent flux, and sensible flux) and near surface climate (i.e., air temperature, water vapor, relative humidity) of China in the past (1978-2004) and also in two future time periods (2050 and 2100) by using the Community Land Model and compared the impact of irrigation with that of LUCC. Meteorological observations in Jilin Province show that the temperature differences between highly and lightly irrigated areas are statistically significant. The differences are highly correlated with the effective irrigation area (EIA) and sown area of crop (CSA). Results from satellite observations show that highly irrigated areas corresponded to lower albedo and daytime land surface temperature (LST), and higher normalized difference vegetation index (NDVI) and evapotranspiration (ET). The difference between highly and lightly irrigated areas is bigger in drier areas and in drier years. The modeling studies show that the irrigation impact on temperature is much less in the future than in the 20th century and that irrigation impacts more on the maximum air temperature than on the minimum air temperature. Both contemporary and future irrigation simulations show, nationally, irrigation decreases daily maximum temperature (Tmax) but increase daily minimum temperature (Tmin). Daily mean temperature (Tmean) decreases in contemporary irrigation simulations but increases in most of the cases in future irrigation simulations. In the 20th century, nationally, the spray irrigation leads to a decrease in Tmax of 0.079K and an increase in Tmin of 0.022K. Nationally, the spray irrigation leads to a decrease in Tmax between 0.022K and 0.045K and an increase in Tmin between 0.019K and 0.057K under future scenarios. This study demonstrates that the irrigation patterns (flood irrigation and spray irrigation) have statistically significant impacts on local climate. Moreover, this study suggests that, in the national respective, the impacts of changes in land management on climate are not comparable to the impacts of changes in land cover land use. This dissertation on irrigation and its impact is the first study which focuses solely on China using observational and modeling methods. The results from this dissertation contribute to a better understanding of the irrigation impact on near-surface climate which can improve our knowledge of how human activities influence climate, guide future policies aimed at mitigating or adapting to climate change, and help design a precise model to project the impact of irrigation on the climate system and irrigation requirements in the future. It can also be useful in assessing future food and water security issues

    An Institutional Design for Sustainable Foreign Forest Carbon Projects in Developing Countries

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    Under the international climate legal regime, many tree planting and forest management activities have been conducted in developing countries with the intention to generate carbon offsets (forest carbon projects). However, studies have shown that some foreign forest carbon projects lead to severely unsustainable results. The current international institutional framework cannot guarantee the long-term environmental and social benefits. This study set out to investigate how to design institutional reforms to promote sustainable results in foreign forest carbon projects in developing countries. The study provides one possible solution to this question that lies in the existing governing systems of multilateral funds. _Part I_ reviews the international institutional framework on forest carbon projects in developing countries using doctrinal and historical approaches. _Part II_ analyses the incentive schemes and the financial streams among major project actors from developed and developing countries. _Part III_ presents a case study of China, which examines the national institutional framework and practices based on interviews and project-site visits. Based on the analysis in the previous parts, Chapter 9 confirms that multilateral funds, which invest in foreign forest carbon projects in developing countries as financial intermediaries between the North and the South, have institutional and economic advantages in addressing the problems identified in the institutional framework and in the incentive schemes. Ten measures are discussed and tailored to address identified problems, based on evidence from practice, and embedded in a workable existing system

    Water Resources Management Models for Policy Assessment

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    This book is a compilation of original research articles that apply a variety of techniques to identify and evaluate water resource management policies. These papers cover a wide range of topics and methodologies applied across the world, from a local to a continental scope. They illustrate open challenges in water resource management, such as the quantitative assessment of policy impacts, trade-off analyses, understanding the water–energy–food–environment nexus, collaborative model development, stakeholder engagement, formalizing social interactions, or improving the theoretical understanding of complex adaptive systems. Therefore, this book is a representation of research areas that have emerged from the origins of water resource systems analysis, seeking to improve the way in which water policy is formulated and implemented

    Water allocation under future climate change and socio-economic development : the case of Pearl River Basin

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    Water shortage has become a major challenge in many parts of the world due to climate change and socio-economic development. Allocating water is critical to meet human and ecosystem needs in these regions now and in the future. However, water allocation is being challenged by uncertainties associated with climate change and socio-economic development. This thesis aims to assess the combined effects of climate change and socio-economic development on water supply and demand in the Pearl River Basin (PRB) in China, and identify water allocation plans, which are robust to future climate change and socio-economic development. To do so, the impact of climate change on future water availability is first assessed. Next, different model frameworks are developed to identify robust water allocation plans for improving reservoir management, ensuring sufficient flow into the delta to reduce salt intrusion, and providing sufficient freshwater for human and industrial consumption under future climate change and socio-economic development. Results show that water availability is becoming more variable throughout the basin due to climate change. River discharge in the dry season is projected to decrease throughout the basin. For a moderate climate change scenario (RCP4.5), low flows reduce between 6 and 48 % depending on locations. For a high climate change scenario (RCP8.5), the decreases of low flows can reach up to 72%. In the wet season, river discharge tends to increase in the middle and lower reaches and decreases in the upper reach of the Pearl River Basin. The variation of river discharge is likely to aggravate water stress. Especially the reduction of low flow is problematic as already the basin experiences water shortages during the dry season in the delta. The model frameworks developed in this study not only evaluate the performance of existing water allocation plans in the past, but also the impact of future climate change on robustness of previous and newly generated water allocation plans. The performance of the four existing water allocation plans reduces under climate change. New water allocation plans generated by the two model frameworks perform much better than the existing plans. Optimising water allocation using carefully selected state-of-the-art multi-objective evolutionary algorithms in the Pearl River Basin can help limit water shortage and salt intrusion in the delta region. However, the current water allocation system with six key reservoirs is insufficient in maintaining the required minimum discharge at two selected gauge stations under future climate change. More reservoirs, especially in the middle and lower reaches of the Pearl River, could potentially improve the future low flow into the delta. This study also explored future water shortage in the Pearl River Basin under different water availability and water use scenarios. Four different strategies to allocate water were defined. These water allocation strategies prioritize upstream water use, Pearl River Delta water use, irrigation water use, and manufacturing water use, respectively. Results show that almost all the regions in the Pearl River Basin are likely to face temporary water shortage under the four strategies. The increasing water demand contributes twice as much as the decreasing water availability to water shortage. All four water allocation strategies are insufficient to solve the water scarcity in the Pearl River Basin. The economic losses differ greatly under the four water allocation strategies. Prioritizing the delta region or manufacturing production would result in lower economic losses than the other two strategies. However, all of them are rather extreme strategies. Development of water resources management strategies requires a compromise between different water users. Optimization algorithms prove to be flexible and useful tool in adaptive water resources allocation for providing multiple approximate Pareto solutions. In addition, new technologies and increasing water use efficiency will be important to deal with future water shortage in the Pearl River Basin.</p
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