Glacier changes and related glacial lake expansion in the Bhutan Himalaya, 1990–2010

This paper discusses the recent retreat of glaciers and the changes in supraglacial lakes in the Bhutan Himalaya during the last two decades. We calculated the changes in clean and debris-covered glaciers and the formation, disappearance, and expansion of glacial lakes during the beginning of 1990s, 2000s, and 2010 using Landsat TM and ETM+ images. For this purpose, eight river sub-basins namely Wang Chu, Chamkar Chu, Dangme Chu, Kuri Chu, Mangde Chu, Mo Chu, Pho Chu and Northern Basin were considered. A retreating trend was found in the case of clean glaciers. Debris-covered glaciers in this region were found to have undergone an increase of about 29 %, and this increase was partially contributed by those expanded upstream. This increase in the debris-covered area is higher on the southern side of the Bhutan Himalaya. It is found that a number of moraine-dammed glacial lakes were formed during this period and can be potentially dangerous depending on the size, distance from the glacier and altitude. Most of the glacial lake formation and expansion occurred on the southern side of the Bhutan Himalaya.     

Climate change threats to environment in the tropical Andes: glaciers and water resources

Almost all of the world’s glaciers in the tropical latitudes are located in the Central Andes (Peru, Bolivia, Ecuador and Colombia). Due to their high altitude, to the high level of radiation and to the tropical climate dynamics, they all are particularly threatened by climate change, as a result of not only warming, but also of changing variability of precipitation. Many glaciers are of crucial importance for the livelihood of the local populations and even for three capitals, Lima (Peru), La Paz (Bolivia) and Quito (Ecuador), which depend on them for water and energy supplies. This paper shows that after a period of increased flow due to the glacier melt disequilibrium, the available water resource will decrease along with the rapid shrinking of the glaciers considered as water reservoirs. The case of the Cordillera Blanca (Peru) is analyzed more in detail with the mid-term (20 years) and long-term (1–2 centuries) impact of the glacier shrinking on the local water resources. Associated risks for the population and consequences for the human activities (tourism, hydropower, agriculture and stock-breeding, large-scale irrigation) are described at each stage of the mountain range.     

Four decades of glacier mass balance observations in the Indian Himalaya

Understanding the glacier mass balance is necessary to explain the rate of shrinkage and to infer the impact of climate change. The present study provides an overview of the glacier mass balance records by glaciological, geodetic, hydrological and accumulation-area ratio (AAR) and specific mass balance relationship methods in the Indian Himalaya since 1970s. It suggests that the mass balance measurements by glaciological methods have been conducted for ten glaciers in the western Himalaya, four glaciers in the central Himalaya and one in the eastern Himalaya. Hydrological mass balance has been conducted only on Siachen Glacier from 1987 to 1991. Geodetic method has been attempted for the Lahaul–Spiti region for a short time span during 1999–2011 and Hindu Kush–Karakoram–Himalaya region from 2003 to 2008. We compared in situ specific balance data series with specific mass balance derived from AAR and specific mass balance relationship. The results derived from existing and newly presented regression model based on AAR and specific mass balance relationship induced unrealistic specific mass balance for several glaciers. We also revised AAR0 and ELA0 based on available in situ AAR and specific mass balance data series of Indian Himalayan glaciers. In general, in situ specific and cumulative specific mass balance observed over different regions of the Indian Himalayan glaciers shows mostly negative mass balance years with a few positive ones during 1974–2012. On a regional level, the geodetic studies suggest that on the whole western, the central and the eastern Himalaya experienced vast thinning during the last decade (2000s). Conversely, Karakoram region showed slight mass gain during almost similar period. However, the glaciological, hydrological and geodetic mass balance data appear to exhibit short time series bias. We therefore recommend creation of benchmark glaciers network for future research to determine the impact of climate change on the Himalayan cryosphere.     

Climatic and human drivers of recent lake-level change in East Juyan Lake,China

Drying of an inland river’s terminal lake in arid regions is an important signal of environmental degradation in downstream regions. A long-term, high-resolution understanding of the lake’s retreat and expansion and the driving mechanisms will inform future adaptive water management strategies, ecosystem restoration, and government decision-making in the context of a growing water scarcity in the inland river basin. The shrubs that grow along the shore of a lake often provide evidence of lake retreat or expansion. The chronological results showed that the earliest germination dates of the lakeshore shrubs, tamarisk, were in 1901, 1943, 1966, 2009, and 1990 from the higher terrace to the lower terrace of East Juyan Lake, a terminal lake of China’s Heihe River. Coupled with river and lake hydrological data, six obvious lake’s fluctuations were identified: shrinkage from 1900 to 1940s and during the early 1990s, expansion and retreat in the late 1950s and early 1970s, continued expansion from 2002 to 2008, and stabilization at a water area of around 40 km² from 2009 to the present. The water elevation in the 1900s was below 905 m a.s.l., resulting in a water area <80 km², but decreased to 40 km² after 1960 and dried up completely by the 1990s. By analysing climatic and hydrological records since 1950, tree-ring climate proxy data, river runoff outside the observation period, and water resource consumption in the middle and lower reaches of the Heihe River, we found that the periodic expansion and retreat of East Juyan Lake was influenced by both climate change and human activities, but especially by human activities. The lake’s recent recovery and stability was achieved by government policy designed to provide environmental flows to the lake.     

LUCC及气候变化对李仙江流域径流的影响

为揭示李仙江流域LUCC和气候变化对径流变化的影响，基于SWAT模型，通过设置不同情景，定量分析了不同土地利用类型和气候要素对流域内径流的影响，并结合RCP4.5、RCP8.5两种气候情景对流域未来径流的变化进行了预估。结果显示：(1) SWAT模型在李仙江流域径流模拟中具有很好的适用性，可以用SWAT模型进行流域的径流模拟，率定期的模型参数R2、Ens分别达到0.74、0.73，验证期的模型参数R2、Ens分别达到0.63、0.63；(2) 单一土地利用情景显示，将农业用地转化为林地或草地，均会导致流域径流量的减少，而将林地转化为草地则会引起流域径流量的增加，农业用地、林地、草地三者对径流增加贡献顺序为农业用地＞草地＞林地。(3) 2006~2015年间李仙江流域的LUCC引起的月均径流增加幅度小于气候变化引起的月均径流减少幅度，李仙江径流的变化由气候变化主导。(4) 在RCP4.5和RCP8.5两种气候情景下，2021~2050年间李仙江流域径流均呈减少趋势，减少的速率分别为3.6和2.15亿m³/10 a，这与1971~2015年间，流域实测径流减速为6.7亿m³/10 a的变化趋势一致，但这两种情景下，径流的减少趋势有所降低，分别为1971~2015年减速的53.7%、32.1%。     

1961～2049年汉江流域降水量变化研究

主要从两个方面对汉江流域的降水进行了研究。一方面,以文献综述法对1961～2011年的汉江流域降水研究文献进行了综述,比较了相关研究结果;另一方面,利用国际比较计划CMIP5中5个全球模式降尺度资料,预估了该地区到2049年的降水趋势变化。综述结果表明,1961～2011年历史时段内,汉江流域整体的降水变化较小,无明显的变化趋势,有近于17和30年的周期变化的结论。模式数据的预估结果表明,1961～2049年内,汉江流域整体上年降水没有明显的上升或下降趋势,在RCP4.5情景下存在着近17和30年的周期变化;但在RCP2.6和RCP8.5情景下,降水周期发生了变化。在RCP2.6情景下,较明显的周期为5和11年;在RCP8.5情景下,较明显的周期为8和17年。总体结论上,文献综述和模式数据的研究结果基本一致,即汉江流域过去50年以及未来30年,降水整体上没有显著的趋势变化。     

Sensitivity of typical Mediterranean crops to past and future evolution of seasonal temperature and precipitation in Apulia

The region of Apulia, which is located in the south-east tip of the Italian Peninsula, has a typical Mediterranean climate with mild winters and hot-dry summers. Agriculture, an important sector of its economy, is potentially threatened by future climate change. This study describes the evolution of seasonal temperature and precipitation from the recent past to the next decades and estimates future potential impacts of climate change on three main agricultural products: wine, wheat and olives. Analysis is based on instrumental data, on an ensemble of climate projections and on a linear regression model linking these three agricultural products to seasonal values of temperature and precipitation. In Apulia, precipitation and temperature time series show trends toward warmer and marginally drier conditions during the whole analyzed (1951–2005) period: 0.18 °C/decade in mean annual minimum temperature and ?14.9 mm/decade in the annual total precipitation. Temperature trends have been progressively increasing and rates of change have become noticeably more intense during the last 25 years of the twentieth century. Model simulations are consistent with observed trends for the period 1951–2000 and show a large acceleration of the warming rate in the period 2001–2050 with respect to the period 1951–2000. Further, in the period 2001–2050, simulations show a decrease in precipitation, which was not present in the previous 50 years. Wine production, wheat and olive harvest records show large inter-annual variability with statistically significant links to seasonal temperature and precipitation, whose strength, however, strongly depends on the considered variables. Linear regression analysis shows that seasonal temperature and precipitation variability explains a small, but not negligible, fraction of the inter-annual variability of these crops (40, 18, 9 % for wine, olives and wheat, respectively). Results (which consider no adaptation of crops and no fertilization effect of CO₂) suggest that evolution of these seasonal climate variables in the first half of the twenty-first century could decrease all considered variables. The most affected is wine production (?20 ÷ ?26 %). The effect is relevant also on harvested olives (?8 ÷ ?19 %) and negligible on harvested wheat (?4 ÷ ?1 %).     

Assessment of climate change simulations over climate zones of Turkey

Projected climate change over Turkey has been analyzed by using the reference (1961–1990) and future (2071–2100) climate simulations produced by ICTP-RegCM3. Since examining Turkey as a single region could be misleading due to the existence of complex topography and different climatic regions, Turkey has been separated into seven climatic regions to evaluate the surface temperature and precipitation changes. Comparison of the reference simulation with observations was made spatially by using a monthly gridded data set and area-averaged surface data compiled from 114 meteorological stations for each climatic region of Turkey. In the future simulation, warming over Turkey’s climatic regions is in the range of 2–5 °C. Summer warming over western regions of Turkey is 3 °C higher than the winter warming. During winter, in the future simulation, precipitation decreases very significantly over southeastern Turkey (24 %), which covers most of the upstream of Euphrates and Tigris river basin. This projected decrease could be a major source of concern for Turkey and the neighboring countries. Our results indicate that a significant increase (48 %) in the autumn season precipitation is simulated over southeastern Turkey, which may help to offset the winter deficit and therefore reduce the net change during the annual cycle.     

Implications of future bioclimatic shifts on Portuguese forests

As climate is an important driver of vegetation distribution, climate change represents an important challenge to forestry. We (1) identify prevailing bioclimatic conditions for 49 relevant forest species in Portugal and (2) assess future shifts under climate change scenarios. We compute two bioclimatic indices (aridity and thermicity) and a new composite index, at ~1 km spatial resolution, and overlap with the species’ current ranges. Locations are based on a digital inventory, while climate parameters for both recent-past (1950–2000) and future climates (2041–2060), under RCP4.5 and RCP8.5, are provided by a multi-model ensemble of climate simulations. Results for future scenarios highlight an overall warming and drying trend. Supramediterranean and mesomediterranean climates will be significantly reduced, while thermomediterranean climates will dramatically increase, from their almost absence in current conditions to an area coverage of ~54 % in 2041–2060 for RCP8.5. There is also a clear shift from hyper-humid and humid to sub-humid and from the latter to semi-arid climates (area coverage of ~13 % in 2041–2060 for RCP8.5). Lower thermomediterranean sub-humid to semi-arid zones will cover the southern half of Portugal. These projections identify the most vulnerable (e.g. Betula pubescens, Quercus pyrenaica and Castanea sativa) and the most adapted (e.g. Quercus suber, Q. rotundifolia, Ceratonia siliqua, Pinus pinea, Quercus coccifera) species in future climates. Current bioclimatic zones associated with Eucalyptus globulus and Pinus pinaster, economically relevant species, will be moderately reduced and relocated. Possible adaptation measures are discussed to improve forest resilience to climate change, while maintaining its economic and environmental benefits.     

Regional climate sensitivity of wetland environments in Rwanda: the need for a location-specific approach

Wetlands are sustaining large communities of people in Rwanda where 10 % of its land surface consists of many local wetlands. Sustainable future management of these numerous wetlands requires a reliable inventory of their location and a dynamic quantitative characterization that allows assessment of their climate change sensitivity. The aim of this study was to assess the importance of climatic factors for determining wetland location at different regional scales. Wetland locations were analyzed and statistically modeled using their location factors with logistic regression. Wetland location probability was determined using topographic (elevation, slope), hydrological (contributing area) and climatic (temperature and rainfall) location factors. A wetland location probability map was made that demonstrated a calibration accuracy of 87.9 % correct at national level compared to an existing inventory, displaying even better fits at subnational level (reaching up to 98 % correct). A validation accuracy of 86.2 % was obtained using an independently collected dataset. A sensitivity analysis was applied to the threshold values used as cutoff value between wetland/non-wetland, demonstrating a robust performance. The developed models were used in a sensitivity scenario analysis to assess future wetland location probability to changes in temperature and rainfall. In particular, wetlands in the central regions of Rwanda demonstrate a high sensitivity to changes in temperature (1 % increase causes a net probable wetland area decline by 12.4 %) and rainfall (+1 % causes a net increase by 1.6 %). This potentially significant impact on wetland number and location probability indicates that climate-sensitive future planning of wetland use is required in Rwanda.     

基于NDVI的重庆市植被覆盖变化及其对气候因子的响应

运用美国NASA发布的MOD13Q1级产品16d最大值合成数据结合重庆市34个气象站点的气候资料,分析2000～2011年重庆市植被变化状况以及NDVI与主要气候因子温度、降水的相互关系。结果表明：12 a来重庆市年均NDVI呈增长趋势,但空间时间尺度上有所差异,从空间尺度上看NDVI增长区域主要分布在东北、东南、西南部区域,NDVI降低区域主要分布在重庆主城区、区县城区及长江沿岸、三峡库区消落带;从时间尺度上看,春季、秋季NDVI有一定幅度的增长,夏季NDVI趋于稳定,冬季NDVI有所下降;NDVI在年际尺度上与温度和降水相关并不显著,但在月份尺度上与气温降水均呈显著相关关系,且与气温相关性大于降水     

How do soil and water conservation practices influence climate change impacts on potato production? Evidence from eastern Canada

We used a stochastic production function method together with a farm-level dataset covering 18 farms over a 23-year period to assess the role that soil and water conservation practices play in affecting the climate change impacts on potato yield in northwestern New Brunswick, Canada. Our analysis accounted for the yield effects of farm inputs, farm technologies, farm-specific factors, seasonal climatic variables, soil and water conservation practices, and a series of interaction terms between soil and water conservation practices and climatic variables. Regression results were used in combination with three climate change scenarios developed by the Intergovernmental Panel on Climate Change (A2, A1B, B1) and four general circulation model predictions over three 30-year time periods (2011–2040, 2041–2070, and 2071–2100) to estimate a range of potato yield projections over these time periods. Results show that accounting for soil and water conservation practices in climate–yield relationships increased the impacts of climate change on potato yield, with yield increases of up to 38 % by the 2071–2100 period. These findings provide evidence that adoption of soil and water conservation practices can help boost potato production in a changing Canadian climate.     

“The End of the Ice Age?”: Disappearing World Heritage and the Climate Change Communication Imperative

Rapid environmental change in vulnerable destinations has stimulated a new form of travel termed “last chance tourism” (LCT). Studies have examined the risks of LCT, while leaving potential opportunities within this new tourism market largely underexplored. Results of survey (n?=?399) research in Jasper National Park, Canada reveal that a LCT motivation influences decisions to visit this iconic Canadian destination, and suggest that this motivation is linked to a desire to learn about the impacts of climate change on the Athabasca Glacier. Findings suggest there may be short to medium term opportunities associated with LCT, including promoting climate change ambassadorship through management interventions. This paper discusses a range of possible education, interpretive, and outreach activities that might be employed at LCT destinations. It outlines the relative merits (or what we refer to as “uneasy benefits”) of promoting the glacier and other LCT destinations within a protected areas management and climate change adaptation context.     

长江流域月降水的EEMD多时间尺度遥相关分析

基于长江流域138个气象站1961~2016年的逐月降水观测资料，应用集合经验模态分解（EEMD）方法，分别对各站点的月降水序列进行EEMD分解，然后，运用时滞相关分析和逐步变量选择的方法，以识别长江流域月降水周期振荡和长期趋势的显著影响因子，并构建多元线性回归模型对长江流域月降水进行预测。结果表明：（1）近50多年来，长江流域各站点的月降水呈现出显著的季节、年际和年代际尺度振荡特征。（2）流域内各站点月降水的长期变化趋势存在着较大的空间差异性，表现为金沙江、雅砻江、大渡河以及鄱阳湖流域是月降水长期趋势显著增加的集中区，而岷江中游以及洞庭湖流域的南部是月降水长期趋势显著减少的集中区。（3）厄尔尼诺1+2区的平均海表温度（NINO1+2）的过去模式是影响长江流域月降水周期振荡的主要气候因子，而全球平均气温距平（GlobalT）是影响长江流域月降水长期趋势的主要气候因子。（4）基于已识别的影响因子构建的月降水量预测模型在旱季的预报性能高于雨季，并在长江上游地区的预报性能高于其中下游地区。     

Hydrologic response to climate change and human activities in a subtropical coastal watershed of southeast China

It is essential to investigate hydrologic responses to climate change and human activities across different physiographic regions so as to formulate sound strategies for water resource management. Mann–Kendall, wavelet and geospatial analyses were coupled in this study, associated with ENSO indicators, flashiness index and baseflow index, in order to explore the hydrologic sensitivity to climate change and human activities in the Jiulong River Basin (JRB), a subtropical coastal watershed of southeast China. The results showed that the average annual precipitation presented an increasing trend (Z = 2.263, p = 0.024) and that this tendency has become weaker from estuary to inland in the JRB over the past 50 years. The annual frequency of rainstorm events increased from 3.4 to 5.2 days in the estuary and from 5.1 to 5.6 days in the West River, whereas it decreased from 6.0 to 5.5 days in the North River from 1954 to 2010. The 10-year average streamflow during 2001–2010 in the North River and West River decreased by 9.2 and 6.7 %, respectively, compared to the average annual streamflow during 1967–2000. Annual fluctuations were the most representative signals in streamflow variability for the North River and West River over the period 1967–2010. Human activities including dam construction, land change and socioeconomic development posed increasing influences on hydrologic conditions in the JRB. Seasonal variability of streamflow and sediment discharge changed significantly between the two periods divided by the jumping point (1992), identified when dams were constructed extensively in the North River and West River. This research provided important insights into the hydrologic consequences of climate change and human activities in a subtropical coastal watershed of southeast China.     

Land cover changes as impacted by spatio-temporal rainfall variability along the Ethiopian Rift Valley escarpment

Magnitudes of land cover changes nowadays can be assessed properly, but their driving forces are subject to many discussions. Next to the accepted role of human influence, the impact of natural climate variability is often neglected. In this paper, the impact of rainfall variability on land cover changes (LCC) is investigated for the western escarpment of the Raya Graben along the northern Ethiopian Rift Valley. First, LCC between 2000 and 2014 were analysed at specific time steps using Landsat imagery. Based on the obtained LCC maps, the link was set with rainfall variability, obtained by means of the satellite-derived rainfall estimates (RFEs) from NOAA-CPC. After a correction by the incorporation of local meteorological station data, these estimates prove to be good estimators for the actual amount of precipitation (ρ _RFE1.0 = 0.85, p = 0.00, n = 126; ρ _RFE2.0 = 0.76, p = 0.00, n = 934). By performing several linear regression analyses, a significant positive relationship between the precipitation parameter DIFF 5Y (i.e. the at-RFE pixel scale difference in five-year average annual precipitation for the two periods preceding the land cover maps) and the changes in the woody vegetation cover was found (standardised regression coefficient β = 0.23, p = 0.02, n = 108). Despite the dominance of direct human impact, further greening of the study area can be expected for the future concomitantly to a wetter climate, if all other factors remain constant.     

Assessment of vulnerability of the eastern Cretan beaches (Greece) to sea level rise

Beaches are both sensitive and critical components of the coastal systems, as they are particularly vulnerable to environmental change (e.g., the sea level rise) and form valuable coastal ecosystems and economic resources. The objective of the present study has been to record the spatial characteristics and other attributes (e.g., topography, sediments and accessibility) of the 71 beaches of the E. Crete (Eastern Mediterranean) that are either already developed or have a reasonable development potential and assess their erosion risk under sea level rise. Beach retreats are predicted by ensembles of six cross-shore (1D) analytical and numerical morphodynamic models, set up/forced on the basis of collected/collated information and three sea level rise scenarios (0.26, 0.82 and 1.86 m); these retreats are then compared with the recorded maximum (dry) beach widths. Projections by the unified ensemble suggest that, in the case of a 0.26 m rise, 80 % of the examined beaches are to retreat by more than 20 and 16 % by more than 50 % of their maximum dry width. In the case of a 0.82 m rise, 72 % of the tested beaches are predicted to retreat by more than 50 % of their dry width and 21 % by a distance at least equal to their observed maximum dry widths. A sea level rise of 1.86 m represents a ‘doom’ scenario, as 75 % of the beaches are predicted to retreat by more than their maximum width. These results may be conservative, as other significant beach erosion factors (e.g., decreasing beach sediment supply) have not been considered.     

Bioclimatic modelling of current and projected climatic suitability of coffee (<Emphasis Type="Italic">Coffea arabica</Emphasis>) production in Zimbabwe

Coffee is an important commodity crop in Zimbabwe and many other African countries in terms of its contribution to local and national economies. Coffee production in terms of productivity and quality face severe constraints due to climate change. A study was therefore carried out to understand and quantify the potential impact of climate change on the coffee sector in Zimbabwe using a bioclimatic modelling approach. Current climatically suitable areas were identified and compared with those areas identified to be climatically suitable under projected 2050 climatic conditions. The projected climatic conditions were obtained from climate predictions of two models: CCSM4 model and HadGEM2 model. Coffee production was found to be mostly sensitive to precipitation factors as these were the most important in determining climatic suitability of coffee production in Zimbabwe. The modelling showed that current coffee suitability varies spatially between the four coffee producing districts in Zimbabwe. Chipinge district has the largest area climatically suitable for coffee production followed by Chimanimani district with Mutare district having the smallest. The modelling predicted that there will be a spatial and quantitative change in climatic suitability for coffee production in Zimbabwe by 2050. The greatest changes are projected for Mutare district where over three quarters according to the CCSM4 model and the entire district according to the HadGEM2 model will turn marginal for coffee production. A westward shift in climatic suitability of coffee was observed for Chipinge and Chimanimani district. The models predicted a loss of between 30,000 ha (CCSM4) and 50,000 ha (HadGEM2) in areas climatically suitable for coffee production by 2050 in Zimbabwe. These changes are likely to be driven by changes in the distribution of precipitation received in the coffee areas. The study presents possible adaptation measures that can be adopted by the coffee sector in Zimbabwe and the region to maintain coffee productivity under a changing climate.     

基于地理加权回归克里金的降水数据融合及其在水文预报中的应用

地理加权回归克里金(GWRK)是在地理加权回归(GWR)基础上扩展得到的一种既能考虑回归关系的空间非平稳性又能考虑回归变量空间自相关性的降水数据融合方法。以赣江流域为例,在评价TRMM卫星数据精度的基础上,分别以GWRK和GWR方法构建了站点-卫星降水数据融合模型,然后采用降水融合数据驱动GR4J水文模型进行水文预报。根据站点尺度降水融合数据精度及水文预报表现,对GWRK和GWR构建的降水融合模型效果进行评价,结果表明:较之GWR方法,GWRK方法能较明显的提高降水融合数据在站点尺度上的精度,但是由于输入到水文模型中的数据为面降水数据,受空间均化的影响,对水文预报精度的提高不如对站点尺度降水融合数据精度的提高明显。     

Land use and socioeconomic influences on a vulnerable freshwater resource in northern New England, United States

Land use and cover conversions as well as climatic factors drive current and future threats to freshwater systems. Research from the United States and across the globe has focused on already threatened and degraded freshwater systems, whose recovery requires significant investments. Attention must also be directed to monitoring freshwater systems that may appear robust, yet are likely to face enhanced vulnerabilities in the future due to climate and land use and cover changes. Such proactive monitoring can help identify problems early and provide potential solutions. In this study, we consider the case of Sebago Lake and its watershed in southern Maine; a region that has experienced significant population growth and development activity. Land use, socioeconomic change and water quality trends are monitored over a 20-year period using Landsat imagery, census, water quality and precipitation data. Our results indicate that Developed Land within the watershed has increased from 5.4 % of the total land area in 1987 to 8.9 % in 2009 with associated increases in population and housing activity. Sebago Lake’s water quality indicators from 1990 to 2010 show a directional trend concomitant with this change. The increase in Developed Land is likely to place additional pressures on water quality in the future. The analysis also indicates that precipitation trends play an important role in water quality variability for Sebago Lake. Predicted changes to climatic factors including enhanced spring time precipitation or earlier ice-out conditions combined with further land use change may play an influential role in determining water quality. The analysis highlights emerging areas of concern and reiterates the essential role of proactively monitoring vulnerable systems to help mitigate future threats.