Land cover change

The present study focuses on the identification and quantification of land-cover changes occurring in the coastal stretches of the East Godavari delta, Andhra Pradesh, India. The analysis of series of multi-temporal satellite data provides an accurate quantification and therefore a better understanding of the process of land-cover changes during 1990-2005. Land-cover changes were quantified based on normalized difference vegetation index (NDVI) image differencing and a post-classification comparison approach. The change detection results were examined in terms of the proportion of land-cover classes and change trajectories with particular emphasis on coastal aquaculture development within the study area. The study shows that the total area under aquacultural ponds increased from 2985 ha in 1990 to 7067 ha in 2005. The major changes in the study area occurred during 1990-1994, when 2873 ha of agricultural land and 762 ha of degraded mangroves were converted into aquacultural ponds. The prediction of landcover distribution in 2010 on the basis of a Markov chain shows a continuing upward trend of the aquaculture area (8267 ha) with less impact on the mangrove area. The analysis predicts that the agricultural land area will continue to decrease from 50 122 to 46 978 ha during 2005-2010.

Scientists need a better and larger set of tools to validate land-use change models, because it is essential to know a model's prediction accuracy. This paper describes how to use the relative operating characteristic (ROC) as a quantitative measurement to validate a land-cover change model. Typically, a crucial component of a spatially explicit simulation model of land-cover change is a map of suitability for land-cover change, for example a map of probability of deforestation. The model usually selects locations for new land-cover change at locations that have relatively high suitability. The ROC can compare a map of actual change to maps of modeled suitability for land-cover change. ROC is a summary statistic derived from several two-by-two contingency tables, where each contingency table corresponds to a different simulated scenario of future land-cover change. The categories in each contingency table are actual change and actual non-change versus simulated change and simulated non-change. This paper applies the theoretical concepts to a model of deforestation in the Ipswich watershed, USA.

This paper presents the applications of Geoinformatics System (GIS) in three different land-use planning (LUP) approaches. The participatory LUP (PLUP) which strongly consider the local people perceptions for land utilizations, the guidelines for LUP by FAO enhanced with multi-criteria evaluation (FAO-MCE), and the land-use planning and analysis system (LUPAS) using interactive multiple-goal linear programming. The case study was two villages in the coastal area of the Mekong Delta (MD), Vietnam. The land use of the studied area is diverse, quickly shifting and strongly contrasting. The contrast is not only in terms of resources but also in economic profitability and environmental sustainability. GIS plays an important role in the successful of these three LUP approaches. In PLUP, GIS help to integrate the acquired spatial and attribute data from farmer discussions and cross-section walks, and to analyses the changes in not only biophysical, land cover changes but also farmers' perception changes in land utilizations. The conflicts in resources uses, mainly between agriculture and aquaculture, were also mapped and described. In FAO-MCE, a GIS was used to combine biophysical and socio-economic characteristics for land evaluation. A multi-criteria evaluation tool was developed to support the decision maker in trade-off among different stakeholders' interests. In LUPAS, an optimization model was developed. The model is linked with a GIS for data input and results presentation. With the optimization model, the land use planners can explore different land use scenarios with different objectives and constraints, both biophysically and socio-economically. The results of the model are sets of land use option maps with their resources requirements, e.g. labor or capital requirements, and their outputs, e.g. productions of shrimp, rice or total area of forest. This information is very important for the decision-maker to select the most suitable land use plan for the study area.

1] The headwater catchments of the Yellow River Basin are of great importance for the whole basin in terms of water resources, and streamflow from these catchments has decreased in the last decades. The concept of climate elasticity was used to assess the impacts of climate and land surface change on the streamflow. Results show that for the period 1960-2000 the elasticity of streamflow in relation to precipitation and potential evapotranspiration are 2.10 and À1.04, respectively, indicating that streamflow is more sensitive to precipitation than to potential evapotranspiration. However, land use change played a more important role than climate in reducing streamflow in the 1990s. It is estimated that land use change is responsible for more than 70% of the streamflow reduction in the 1990s, while climate change contributed to less than 30% of the reduction.

This paper aims to present a methodology to link analysis process to the development of land cover change model. We developed a method to partitioning the study area, located at Central-North region of Rondônia, in land units, characterized by history of occupation using a TM/Landsat image series, from 1985 to 2000 and a geographic database to store spatial and non-spatial information. Land Unities, called UOP, express different land cover patterns linked to different deforestation process in time and space. The UOP mapping allowed us to analyze the study area throughout deforestation indicators and to capture the diversity of occupation processes and some factors that affects deforestation distribution. This work allowed us to define some computational modeling requirement to support Rondônia space-time complexity as, multiple resolutions, multiple times events, multiple actors and behaviors.

Anthropogenic land cover change (ALCC) is one of the few climate forcings with still unknown sign of their climate response. Major uncertainty results from the often counteracting temperature responses to biogeochemical as compared to biogeophysical effects. Here, we separate the strength of these two effects for ALCC during the last millennium. We add unprecedented detail by (i) using a coupled atmosphere/ocean general circulation model (GCM), and (ii) applying a high-detail reconstruction of historical ALCC. We find that biogeophysical effects have a slight cooling influence on global mean temperature (-0.03 K in the 20th century), while biogeochemical effects lead to strong warming (0.16-0.18 K). During the industrial era, both effects cause significant changes in certain regions; only few regions, however, experience biogeophysical cooling strong enough to dominate the overall temperature response. This study therefore suggests that the climate response to historical ALCC, both globally and in most regions, is dominated by the rise in CO 2 caused by ALCC emissions.

This paper illustrates the result of land use/ cover change in Dhaka Metropolitan of Bangladesh using topographic maps and multi-temporal remotely sensed data from 1960 to 2005. The Maximum likelihood supervised classification technique was used to extract information from satellite data, and post-classification change detection method was employed to detect and monitor land use/cover change. Derived land use/cover maps were further validated by using high resolution images such as SPOT, IRS, IKONOS and field data. The overall accuracy of land cover change maps, generated from Landsat and IRS-1D data, ranged from 85% to 90%. The analysis indicated that the urban expansion of Dhaka Metropolitan resulted in the considerable reduction of wetlands, cultivated land, vegetation and water bodies. The maps showed that between 1960 and 2005 built-up areas increased approximately 15,924 ha, while agricultural land decreased 7,614 ha, vegetation decreased 2,336 ha, wetland/lowland decreased 6,385 ha, and water bodies decreased about 864 ha. The amount of urban land increased from 11% (in 1960) to 344% in 2005. Similarly, the growth of landfill/bare soils category was about 256% in the same period. Much of the city's rapid growth in population has been accommodated in informal settlements with little attempt being made to limit the risk of environmental impairments. The study quantified the patterns of land use/cover change for the last 45 years for Dhaka Metropolitan that forms valuable resources for urban planners and decision makers to devise sustainable land use and environmental planning.

It is well known that rivers connect upstream and downstream ecosystems within watersheds. Here we describe the concept of precipitationsheds to show how upwind terrestrial evaporation source areas contribute moisture for precipitation to downwind sink regions. We illustrate the importance of upwind land cover in precipitationsheds to sustain precipitation in critically water stressed downwind areas, specifically dryland agricultural areas. We first identify seven regions where rainfed agriculture is particularly vulnerable to reductions in precipitation, and then map their precipitationsheds. We then develop a framework for qualitatively assessing the vulnerability of precipitation for these seven agricultural regions. We illustrate that the sink regions have varying degrees of vulnerability to changes in upwind evaporation rates depending on the extent of the precipitationshed, source region land use intensity and expected land cover changes in the source region.

Tropical deforestation remains a critical issue given its present rate and a widespread consensus regarding its implications for the global carbon cycle and biodiversity. Nowhere is the problem more pronounced than in the Amazon basin, home to the world's largest intact, tropical forest. This article addresses land cover change processes at household level in the Amazon basin, and to this end adapts a concept of domestic life cycle to the current institutional environment of tropical frontiers. In particular, it poses a risk minimization model that integrates demography with market-based factors such as transportation costs and accessibility. In essence, the article merges the theory of Chayanov with the household economy framework, in which markets exist for inputs (including labor), outputs, and capital. The risk model is specified and estimated, using survey data for 261 small producers along the Transamazon Highway in the eastern sector of the Brazilian Amazon.

Maps of current and potential vegetation spatial patterns can be used to assess land cover changes, and aid in ecosystem management and restoration. The vegetation spatial patterns of subalpine forest species are largely controlled by variation in temperature, water and solar radiation resources. These fundamental resources were quantified across a 1100-km 2 landscape using biophysical models, a digital elevation model (DEM), and weather station data. Field data of species abundances were used to define species-habitat relationships and calibrate maximum likelihood classifications of the biophysical gradients. For comparison, a standard land cover classification of Landsat Thematic Mapper satellite imagery had an overall accuracy 68.3%. Using the biophysical gradients alone gave a similar 67.4% accuracy. The highest accuracy classification (83.2%) used both biophysical and spectral data. The biophysical resources were also used to map the presence or absence of four herb and shrub species that cannot be sensed remotely. These predictions ranged from 60% to 79% accurate. Maps of relative abundance were less accurate, from 61% to 63.2%. This low result may be due to historical and stochastic events, or simply a small data set. The spatial pattern of species and communities that are controlled by resources can be predicted using general biophysical models. The species-habitat relationships can also be used to improve remote sensing products.

Renó, V. F.; Novo, E. M. L. M.; Suemitsu, C.; ; Rennó, C. D.; SILVA, Thiago S. F. (2011).

The floodplain forests bordering the Amazon River have outstanding ecological, economic, and social importance for the region. However, the original distribution of these forests is not well known, since they have suffered severe degradation since the 16th century. The previously published vegetation map of the Amazon River floodplain (Hess et al., 2003), based on data acquired in 1996, shows enormous difference in vegetation cover classes between the regions upstream and downstream of the city of Manaus. The upper floodplain is mostly covered by forests, while the lower floodplain is predominantly occupied by grasses and shrubs.This study assesses deforestation in the Lower Amazon floodplain over a ~ 30 year period by producing and comparing a historical vegetation map based on MSS/Landsat images acquired in the late 1970s with a recent vegetation map produced from TM/Landsat images obtained in 2008. The maps were generated through the following steps: 1) normalization and mosaicking of images for each decade; 2) application of a linear mixing model transformation to produce vegetation, soil and shade fraction-images; and 3) object-oriented image analysis and classification. For both maps, the following classes were mapped: floodplain forest, non-forest floodplain vegetation, bare soil and open water. The two maps were combined using object-level Boolean operations to identify time transitions among the mapped classes, resulting in a map of the land cover change occurred over ~ 30 years. Ground information collected at 168 ground points was used to build confusion matrices and calculate Kappa indices of agreement. A survey strategy combining field observations and interviews allowed the collection of information about both recent and historical land cover for validation purposes. Kappa values (0.77, 0.75 and 0.75) indicated the good quality of the maps, and the error estimates were used to adjust the estimated deforested area to a value of 3457 km2 ± 1062 km2 (95% CI) of floodplain deforestation over the ~ 30 years.

Tropical montane forests have been recognised as having global conservation importance. However, they are being rapidly destroyed in many regions of the world. Our study focuses on the rate of loss and patterns of fragmentation in tropical montane forests in the Highlands of Chiapas, Mexico, during a 25-year period. Data from Landsat satellite imagery from 1975 (MSS), 1990 (TM) and 2000 (ETM+) were used to ascertain annual deforestation rates of 1.3 and 4.8% for the 1975-1990 and 1990-2000 periods, respectively. Spatial patterns of forest fragmentation were identified using selected landscape indices. Increases in the number of forest fragments (3520-10,542), patch density (1.0-3.2 patches/100 ha), and total edge length (24,781-38,400 km) were associated with decreases in the mean patch size (65.0-8.7 ha), largest patch index (60.7-4.0%), total core area (99,422-9,611 ha), and mean proximity index (101,369-1405). The observed trends indicate increasing deforestation and fragmentation, particularly during the 1990-2000 period. Circa 50% of the forest cover in the Highlands has been lost in 25 years, and a proportion of the remaining forests have been degraded as a result of human use. Increasing human population and a more demanding use of soils for agriculture and timber arise as the major causes of deforestation in the study area. We suggest that conservation efforts should be focused on the management of the natural system and the management of the external influences on it, particularly the detection of hotspots, passive and active restoration and sustainable forest exploitation by the local indigenous communities. # Maximum probability for evidence derived from expert knowledge was set at 0.8 thus allowing uncertainty to be incorporated in the classification procedure. MCF = montane cloud forest; OF = oak forest; POF = pine-oak forest; PF = pine forest; CP = coffee plantation; NF = non-forest.

Efficient natural resources management, including continental water at watershed level, requires understanding the arrangement of landscape attributes in a region. The geographical analysis of landscape attributes is a useful approach to delineate relatively homogeneous watersheds or regions. This research was carried out in order to evaluate the effect of land cover through time on regionalisation modelling in the poorly-gauged Cuitzeo Lake Watershed, and to develop models to create two hydrogeographical regionalisations for the years 1975 and 2000. The inputs required by the regionalisation methodology were integrated in a GIS and validated before carrying out statistical regionalisation procedures (cluster analysis and PCA). GIS operations were done in Arc View 3.2 and statistical analyses in PC-ORD. Median Euclidean distances with mean distance linkage methods were used. A 75% of similarity was chosen as the threshold to generate regions. Importance rankings of regions were obtained using multicriteria evaluation methods. Based on the analysis, 38 of the 52 subwatersheds belonging to the Cuitzeo Lake Watershed were clustered; eight groups were defined in 1975 and nine in 2000. According to PCA, the strongest positive variables are associated to morphometric, geologic, land cover and soil attributes. Fourteen subwatersheds were never clustered. Four subwatersheds changed of cluster between 1975 and 2000. This change is explained because of rainfed agricultural parcel abandonment, and subsequent shrubland growth. This means that the hydrogeographical regionalisation is sensitive to land cover change processes. The methodological approach applied in this research is a low-cost and fast alternative for evaluating the impact of land cover and land use change on hydrogeographical regionalisation; in consequence, data and information generated during the analysis were made available to local authorities so that they can improve both water resources planning and their informational baseline for decision making and for development of environmental policies in the Cuitzeo Lake Watershed.

Measuring and mapping human influence at the global scale suffers from problems of accuracy and resolution. To evaluate the magnitude of this problem we mapped the Human Footprint (HF) for the Northern Appalachian/Acadian ecoregion at a 90-m resolution using best available data on human settlement, access, land use change, and electrical power infrastructure. Such a map measures the magnitude of human transformation of a landscape, scaled between Human Footprint scores of 0 and 100. Comparison with a 1-km resolution Global Human Footprint map revealed similar spatial patterns of human influence. The correlation between HF scores, however, declined with the size of the area compared, with the rank correlation between ecoregional and global HF scores ranging between 0.67 for 100% of the ecoregion and 0.41 for 0.1% of the ecoregion. This indicates that rescaling the map to a finer resolution leads to improvements that increase as the planning area becomes smaller. The map reveals that 46% of the ecoregion has HF ≤ 20 (compared to 59% in the global analysis) and 34% had HF > 40 (compared to 21% in the global analysis). These results demonstrate the benefit of performing region-scale Human Footprint mapping to support conservation-based land use planning at the ecoregional to the local scale. This exercise also provides a data framework with which to model regionally plausible Future Human Footprint scenarios. These and other benefits of producing a regional-scale Human Footprint must be carefully weighed against the costs involved, in light of the region's conservation planning needs.

Dryland degradation rarely translates into linear, declining trends in vegetation cover due to interannual climatic variability. Appropriate indicators of landcover modifications need to be defined for semi-arid regions. Our hypothesis is that degradation can be measured by: (1) a decrease in the resilience of vegetation to droughts; (2) a decrease in rain-use efficiency; and (3) a modification of floristic composition. The objective of this paper is to test the relationships between a remotely sensed indicator of vegetation, rainfall data and field measurements of biomass and floristic composition. The study was based on field measurements of vegetation conditions covering a period of 10 years, in the semi-arid region of the Ferlo in Senegal. Our results indicate that land-cover modifications in the Ferlo are best measured by changes in rain-use efficiency. No consistent trend in the relative abundance of grass species was visible at the scale of the decade, even on the two sites affected by degradation. Just after a drought, a given increase in rainfall results in less biomass production than is the case for normal years.

In the last decades, the detection of drought occurrences and assessment of its severity using satellite data are becoming popular in disaster, desertification, crop production, phenology, land cover change and climate change studies. To detect the drought effects on different vegetation types, many methodologies have been developed, mostly relying on the use of vegetation indices. This communication reports the first attempt to assess the capability of MODIS NDVI, Enhanced Vegetation Index (EVI) and Normalized Difference Water Index (NDWI) from 2000 to 2006 time-series to detect the 2005 drought in Amazonia. To reach this objective, monthly composites of the MOD13A2 product were generated from period. Then, monthly anomalies were calculated, considering anomalous values when lower than-1 standard deviation (sd) or higher than 1 sd. Rainfall data provided by the Tropical Rainfall Measuring Mission (TRMM) was also acquired for the same time-series with the objective of supporting the understanding of vegetation response with the precipitation. Water deficit data calculated based on the TRMM data were also used to guide the sampling scheme. A land cover map for South America updated with natural land cover changes detected by the Near Real Time Deforestation Detection Project (DETER) was used as a mask to avoid false anomalies in the Brazilian Amazon. In general, NDWI and EVI showed to be sensitive and consistent for the temporal series used. NDVI presented a high variability and though a difficult interpretation. Critical months in the NDWI and EVI series coincided with the months with higher water stress calculated based on the TRMM data. EVI also showed to detect changes in the canopy structure. These preliminary results suggest that this is a strong methodology to be used in the spatial analysis of the extent of the drought effects in the vegetation. Literfall data will be incorporate in this research for validation purposes.

The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is a high spatial resolution, multispectral imager with alongtrack stereo capabilities scheduled for launch on the first NASA spacecraft of the Earth Observing System (EOS AM-1) in mid-199 . Data will be obtained in 14 spectral bands covering the visible through the < hermal infrared wavelength region. A number of standard data products will be available to requesters through an on-line archival and processing system. Particular, user-specified data acquisitions will be possible through a Data Acquisition Request system. res0000913 06-09-99 2 0 : 5 7 : 4 0 R.-W 1 4 -0 5 r e s 0 0 0 0 9 1 3 0 6 -0 9 -9 9 2 0 : 5 7 : 4 0 R e v 1 4 . 0 5 The Charlesworth Group, Huddersfield 01484 517077

Understanding the terrestrial carbon budget, in particular the strength of the terrestrial carbon sink, is important in the context of global climate change. Considerable attention has been given to woody encroachment in the western US and the role it might play as a carbon sink; however, in many parts of the western US the reverse process is also occurring. The conversion of woody shrublands to annual grasslands involves the invasion of non-native cheatgrass (Bromus tectorum) which in turn leads to increased frequency and extent of fires. We compared carbon storage in adjacent plots of invasive grassland and native shrubland. We scaled-up the impact of this ecosystem shift using regional maps of the current invasion and of the risk of future invasion. The expansion of cheatgrass within the Great Basin has released an estimated 8 AE 3 Tg C to the atmosphere, and will likely release another 50 AE 20 Tg C in the coming decades. This ecosystem conversion has changed portions of the western US from a carbon sink to a source, making previous estimates of a western carbon sink almost certainly spurious. The growing importance of invasive species in driving land cover changes may substantially change future estimates of US terrestrial carbon storage.

The study of land cover change is an important problem in the Earth Science domain because of its impacts on local climate, radiation balance, biogeochemistry, hydrology, and the diversity and abundance of terrestrial species. Most well-known change detection techniques from statistics, signal processing and control theory are not well-suited for the massive high-dimensional spatio-temporal data sets from Earth Science due to limitations such as high computational complexity and the inability to take advantage of seasonality and spatio-temporal autocorrelation inherent in Earth Science data. In our work, we seek to address these challenges with new change detection techniques that are based on data mining approaches. Specifically, in this paper we have performed a case study for a new change detection technique for the land cover change detection problem. We study land cover change in the state of California, focusing on the San Francisco Bay Area and perform an extended study on the entire state. We also perform a comparative evaluation on forests in the entire state. These results demonstrate the utility of data mining techniques for the land cover change detection problem.

Long-term historical records of rainfall (P), runoff (Q) and other climatic factors were used to investigate hydrological variability and trends in the Volta River Basin over the period 1901-2002. Potential (E p ) and actual evaporation (E), rainfall variability index (d), Budyko's aridity index (I A ), evaporation ratio (C E ) and runoff ratio (C Q ) were estimated from the available hydroclimatological records. Mann-Kendall trend analysis and non-parametric Sen's slope estimates were performed on the respective time series variables to detect monotonic trend direction and magnitude of change over time.

This study integrated remote sensing, household survey data, and spatial modeling to assess drivers of deforestation within the Community Baboon Sanctuary (CBS), Belize, an IUCN category IV protected area for the black howler monkey (Alouatta pigra) established in 1985. We contrasted land-cover trends within the CBS, as well as a 120 m river buffer running within and outside the CBS (the focus of conservation). Additionally, we assessed the relative influence of selected household economic activity and demographic data, participation in two conservation initiatives, locational context, and land tenure on the probability of deforestation using binomial logit models. Social survey and land-cover change data was incorporated from 33 smallholder parcels from the years 2000-2004. Deforestation rates within the CBS totaled 30% between 1989 and 2004, following similar trends in Belize. Riparian areas were more likely to be deforested, as were areas closer to roads. Although cattle correlated with the leading driver of deforestation in the model, land tenure was not influential, despite its importance within the literature. Although involvement with conservation initiatives is correlated with decreased deforestation, other drivers are more influential, stressing the influence of other competing factors on forest preservation that must be considered with conservation development.

Amazonian forest fragments and secondgrowth forests often differ substantially from undisturbed forests in their microclimate, plant-species composition, and soil fauna. To determine if these changes could affect litter decomposition, we quantified the mass loss of two contrasting leaf-litter mixtures, in the presence or absence of soil macroinvertebrates, and in three forest habitats. Leaf-litter decomposition rates in second-growth forests (>10 years old) and in fragment edges (<100 m from the edge) did not differ from that in the forest interior (>250 m from the edges of primary forests). In all three habitats, experimental exclusion of soil invertebrates resulted in slower decomposition rates. Faunal-exclosure effects were stronger for litter of the primary forest, composed mostly of leaves of old-growth trees, than for litter of second-growth forests, which was dominated by leaves of successional species. The latter had a significantly lower initial concentration of N, higher C:N and lignin:N ratios, and decomposed at a slower rate than did litter from forest interiors. Our results indicate that land-cover changes in Amazonia affect decomposition mainly through changes in plant species composition, which in turn affect litter quality. Similar effects may occur on fragment edges, particularly on very disturbed edges, where successional trees become dominant. The drier microclimatic conditions in fragment edges and second-growth forests (>10 years old) did not appear to inhibit decomposition. Finally, although soil invertebrates play a key role in leaf-litter decomposition, we found no evidence that differences in the abundance, species richness, or species composition of invertebrates between disturbed and undisturbed forests significantly altered decomposition rates.

We analysed land cover change processes over a 28-year time period in Central Mexico, by means of integration of existing databases of land cover and land use (1975 and 2000), and updating through visual interpretation of Landsat MSS and ETM þ satellite images and orthophotos (1986, 1996 and 2003). Multitemporal analyses included mapping, evaluation of transition matrices, computation of rates of land use change for the main change processes during each period, and cluster analysis. We used watersheds, subdivided both as sub-watersheds and functional zones, as units of analyses. The processes of land use change in the area were not constant, as most of the land use changes took place over a period of less than ten years. This specific period coincided with both the Immigration Reform and Control Act of 1986, and a major catastrophic earthquake in central Mexico in 1985. Similarly, processes of land use change differed during the periods of analyses in the watershed functional zones. The methodological approach applied in this analysis integrates standard procedures to evaluate land cover and land use change in watersheds. Due to the practical value of the results, the data and information generated during the analysis have been made available to local authorities.

ÖZET: Hızla artan dünya nüfusu ve teknolojik gelişmeler doğal kaynaklar üzerinde yoğun bir baskı oluşturmaktadır. Tarım, ormancılık, hayvancılık, ulaşım, barınma gibi beşeri faaliyetler nedeniyle araziye olan ihtiyaç her geçen gün artmakta ve böylece toprağın doğal yapısı ve işlevi değişmektedir. Bununla birlikte pek çok çevre sorunu yanlış arazi kullanımından kaynaklanmakta olup iklim değişikliği, biyolojik çeşitliliğin azalması veya yok olması, su, toprak ve havanın kirlenmesi gibi birçok çevre sorunu arazinin yanlış kullanımı sonucu ortaya çıkmaktadır. Arazi kullanımından kaynaklanan sorunları en aza indirmek için arazi özelliklerinin çok iyi bilinmesi ve planlanması gerekmektedir. Bu nedenle yerel ölçekli, ayrıntılı çalışmalar yapmak büyük önem taşımaktadır. Bu tür çalışmalarda doğru sonuçlara daha kısa sürede ulaşmak için teknolojik imkânlardan yararlanmak gerekmektedir. Son zamanlarda Uzaktan Algılama ile elde edilen veriler, arazi örtüsünün zamansal değişimini ortaya koymada yaygın olarak kullanılmaktadır. Bu çalışmada, Elbistan Ovasında arazi örtüsü ve arazi kullanımındaki zamansal değişimler farklı tarihlere ait uydu görüntüleri kullanılarak tespit edilmiştir. İlk aşamada Landsat uydu görüntülerine çeşitli sınıflama teknikleri uygulanmış ve arazi örtüsü sınıfları belirlenmiştir. Daha sonra oluşturulan sınıflar zamansal olarak karşılaştırılmış ve meydana gelen değişimler tespit edilmiştir. Yapılan incelemeler sonucunda başta yerleşim alanları olmak üzere arazi kullanımı ve arazi örtüsünde önemli değişimlerin olduğu gözlenmiştir.

In this paper we analyze the historic trends in thermal comfort (measured in terms of Temperature-Humidity Index [THI] and Relative Strain Index [RSI]) in the Sri Lankan primate city of Colombo and correlate them with land cover changes in the region. Land cover is calculated form time-series aerial photographs in terms of ''hard'' cover (buildings, paved areas and roads) and ''soft'' cover (trees, green areas and waterbodies). The period selected for analysis includes pre-rapid (up to 1977) and rapid urban phases (1978 onwards) in the city. Contemporary Sri Lanka's urbanization is peculiar in that mid to late 20th century urban rates (approx. 22% of the population) had remained virtually unchanged till the economy was liberalized in 1977, but have recently intensified (currently at about 35%). This offers a unique window of opportunity to look at the thermal comfort transition consequent to urbanization. Since many tropical cities are at a similar stage of demographic transition, lessons from Colombo may generally be applicable to other tropical developing cities as well. An increasing trend in thermal discomfort-particularly at night-is seen especially at the suburban station and it correlates well with hard land cover changes. The study also brings out the relative importance of land cover in city center vs. rural areas (e.g. hard cover has more effect on thermal discomfort in city center than in rural areas). Based on these findings, we postulate an outline for a climate-sensitive urban design policy for tropical cities.

This paper describes the establishment of a GIS database for environmental planning and management in the economically most active, and environmentally threatened northeastern part of Viet Nam. The database is structured into 5 main groups of data covering: basic geography, soil and land use/ cover, coastline, human activities, and pollution data. There is a further subdivision over 45 data layers covering issues that range from protected areas and green spaces, over transport infrastructure to basic relief geographical data. Two aspects of the use of this database are discussed in more detail: (a) land use changes during the period 1988-1998. The results of this analysis show to which extent urbanization took place in the Ha Long area. (b) coastal line changes which are induced by both natural and human activities. During the period 1988-1998 in the wider Ha Long bay area 894 ha of water and 124 ha of mangroves were converted into development land.

The extent and the spatial patterns of landscape transformation we observe today are the result of the historic human settlement process, often dating back hundreds or thousands of years. Analyzing and reconstructing those historical patterns helps to advance the understanding of the dynamics and persistence of present-day ecosystems. This article explores this reconstruction by identifying and analyzing historic drivers of landscape change for seven periods between 1500 and 2000, and presents historical land use maps ...

This paper presents an integrated study of urbanization trends in Shijiazhuang City, Hebei Province of China, by using Geographical Information Systems (GIS) and remote sensing. The study explores the temporal and spatial characteristics of urban expansion from 1934 to 2001, and land use/cover change from 1987 to 2001. Temporally, urban expansion shows fast and slow growth stages, with the high-speed growth districts shifting to the east or west side of the city. The spatial patterns of urban growth can be categorized into three types: special objectives oriented type, social-political intervention type, and normal urban growth type. The remotely detected land use/cover change from 1987 to 2001 shows that the land use/cover was largely changed. The land use/cover conversion relationship implies that these changes are governed by urban expansion, which produces a force to drive the land use changes in search of a higher return. Lastly, the major factors influencing urban expansion and land use/cover change are also discussed. In general, the population, traffic conditions, industrialization, and policy are the major factors that influenced the urban expansion.

Biodiversity has been recognized as one of the key components of environmental sustainability. Assessment of biodiversity trends and progress toward targets requires effective and sound indicators. In our article, we review and compare the leading multispecies biodiversity indices used in global and regional assessments. We reviewed basic characteristics of these aggregated and composite biodiversity indicators and evaluated them with regard to their ecological performance, policy relevance and other accounting aspects. Indices analyzed include species and populations based indicators, such as Living Planet Index and Red List Index, as well as ecosystem based indicators like Natural Capital Index and Biodiversity Intactness Index. We also include measures of ecological integrity such as Marine Trophic Index and Index of Biotic Integrity. Indicators analyzed differ in both their ecological focus, baselines, basic units or policy use. Multispecies biodiversity indices illustrate prevailingly negative trends in the state of nature as a result of human induced pressures, especially land cover change. Biodiversity loss is therefore not decoupled from socioeconomic progress. We show that current indicators include a balanced mix of important biodiversity aspects and have some policy resonance. Leading biodiversity indices should be further promoted and integrated into monitoring, modelling and decision-making frameworks.

The rich biodiversity of southern Africa has to date been relatively unimpacted by the activities of modern society, but to what degree will this situation persist into the 21st century? We use a leading global environmental assessment model (IMAGE) to explore future land use and climate change in southern Africa under the scenarios developed by the Millennium Ecosystem Assessment. We assess the impacts on terrestrial biodiversity using the Biodiversity Intactness Index, which gives the average change in population size relative to the pre-modern state, across all terrestrial species of plants and vertebrates. Over the coming century, we project absolute declines in the average population sizes of these taxa that are two to three times greater than the reductions that have occurred since circa 1700. Our results highlight the immense challenges faced by efforts to reduce rates of biodiversity loss in southern Africa, even under relatively optimistic scenarios. These results stress the urgent need for better aligning biodiversity conservation and development priorities in the region. Furthermore, we suggest that context-sensitive conservation targets that account for the development imperatives in different parts of the region are needed. r

The Mediterranean island landscape is a mosaic of land-cover types that manifest the historical interaction between physical and anthropogenic processes that have affected significantly landscape composition and spatial configuration. The aim of this study is to investigate the processes and patterns of landscape changes in small Mediterranean islands as exemplified by the Aegean island of Sifnos, Greece. Satellite imagery was used to measure land-cover changes from 1987 to 1999. A suite of landscape metrics was employed to quantify changes in landscape structure. The results show that cropland suffered the highest area loss through conversions to semi-natural vegetation or settlements. The maquis vegetation of Juniperus phoenicea expanded over time with hotspots of expansion mainly located away from settlements. Overall, Sifnos' landscape became less fragmented and more homogeneous. The main drivers of landscape change were agricultural decline and tourism. These processes have resulted in semi-natural vegetation expansion and landscape closure. Landscape polarization of land-use intensity has increased with anthropogenic processes operating only on certain locations close to settlements and large parts of the island loosing their productivist profile. However, tourism should not be considered as the primary cause of land-use polarization but rather as an aggravating factor; agriculture and tourism do not represent competing economic sectors and land-use polarization is mainly the outcome of spatially co-occurring rather than spatially competing processes. Aegean island landscapes' management needs to be pragmatic and as such adaptable to future emerging priorities.

Among the main effects of human activities on the environment are land use and resulting land cover changes. Such changes impact the capacity of ecosystems to provide goods and services to the human society. This supply of multiple goods and services by nature should match the demands of the society, if self-sustaining human-environmental systems and a sustainable utilization of natural capital are to be achieved. To describe respective states and dynamics, appropriate indicators and data for their quantification, including quantitative and qualitative assessments, are needed. By linking land cover information from, e.g. remote sensing, land survey and GIS with data from monitoring, statistics, modeling or interviews, ecosystem service supply and demand can be assessed and transferred to different spatial and temporal scales. The results reveal patterns of human activities over time and space as well as the capacities of different ecosystems to provide ecosystem services under changing land use. Also the locations of respective demands for these services can be determined. As maps are powerful tools, they hold high potentials for visualization of complex phenomena. We present an easy-to-apply concept based on a matrix linking spatially explicit biophysical landscape units to ecological integrity, ecosystem service supply and demand. An exemplary application for energy supply and demand in a central German case study region and respective maps for the years 1990 and 2007 are presented. Based on these data, the concept for an appropriate quantification and related spatial visualization of ecosystem service supply and demand is elaborated and discussed.

International union for conservation of nature (IUCN) red list Land-cover change Parks Urban sprawl A B S T R A C T Due to human population growth and migration, there will be nearly 2 billion new urban residents by 2030, yet the consequences of both current and future urbanization for biodiversity conservation are poorly known. Here we show that urban growth will have impacts on ecoregions, rare species, and protected areas that are localized but cumulatively significant. Currently, 29 of the world's 825 ecoregions have over one-third of their area urbanized, and these 29 ecoregions are the only home of 213 endemic terrestrial vertebrate species. Our analyses suggest that 8% of terrestrial vertebrate species on the IUCN Red List are imperiled largely because of urban development. By 2030, 15 additional ecoregions are expected to lose more than 5% of their remaining undeveloped area, and they contain 118 vertebrate species found nowhere else. Of the 779 rare species with only one known population globally, 24 are expected to be impacted by urban growth. In addition, the distance between protected areas and cities is predicted to shrink dramatically in some regions: for example, the median distance from a protected area to a city in Eastern Asia is predicted to fall from 43 km to 23 km by 2030. Most protected areas likely to be impacted by new urban growth (88%) are in countries of low to moderate income, potentially limiting institutional capacity to adapt to new anthropogenic stresses on protected areas. In short, trends in global ecoregions, rare species, and protected areas suggest localized but significant biodiversity degradation associated with current and upcoming urbanization.

The conversion of landscapes by human activities results in widespread changes in landscape spatial structure. Regardless of the type of land conversion, there appears to be a limited number of common spatial configurations that result from such land transformation processes. Some of these configurations are considered optimal or more desirable than others. Based on pattern geometry, we define ten pro-cesses responsible for pattern change:

This study aims to predict the spatial distribution of tropical deforestation. Landsat images dated 1974Landsat images dated , 1986Landsat images dated and 1991 were classified in order to generate digital deforestation maps which locate deforestation and forest persistence areas. The deforestation maps were overlaid with various spatial variables such as the proximity to roads and to settlements, forest fragmentation, elevation, slope and soil type to determine the relationship between deforestation and these explanatory variables. A multi-layer perceptron was trained in order to estimate the propensity to deforestation as a function of the explanatory variables and was used to develop deforestation risk assessment maps. The comparison of risk assessment map and actual deforestation indicates that the model was able to classify correctly 69% of the grid cells, for two categories: forest persistence versus deforestation. Artificial neural networks approach was found to have a great potential to predict land cover changes because it permits to develop complex, non-linear models.

Land-use change is related to climate change as both a causal factor and a major way in which the effects of climate change are expressed. As a causal factor, land use influences the flux of mass and energy, and as land-cover patterns change, these fluxes are altered. Projected climate alterations will produce changes in land-cover patterns at a variety of temporal and spatial scales, although human uses of the land are expected to override many effects. A review of the literature dealing with the relationship between land-use change and climate change clearly shows that (1) in recent centuries land-use change has had much greater effects on ecological variables than has climate change; (2) the vast majority of land-use changes have little to do with climate change or even climate; and (3) humans will change land use, and especially land management, to adjust to climate change and these adaptations will have some ecological effects. Therefore, an understanding of the nonclimatic causes of land-use change (e.g., socioeconomics and politics) are necessary to manage ecological functions effectively on regional and global scales.

The ASTER also has a backlooking VNIR telescope, thus, stereoscopic images are acquired at 15-m resolution. ASTER was built to serve different application areas as vegetation and ecosystem dynamics, hazard monitoring, geology and soils studies, land surface climatology, hydrology, and land cover change. The main aim of this article is to illustrate the ASTER's ability to provide an information for alteration minerals, which are valuable for mineral prospecting and exploration activities. Several band ratio composite images, highlighting the possible distributions of iron oxides and clay minerals in the area of Assarel and Medet ore deposits are given. The iron and alteration minerals spreading form two stripes, related to the faulting zones which control the development of mineral deposits and numerous ore occurrences in the studied area.

In a recent paper in this journal, Bradshaw and colleagues analyse country statistics on flood characteristics, land cover and land cover change, and conclude that deforestation amplifies flood risk and severity in the developing world. The study addresses an important and long-standing question, but we identify important flaws. Principal among these are difficulties in interpreting country statistics and the correlation between population and floods. We review current knowledge, which suggests that the removal of trees does not affect large flood events, although associated landscape changes can under some circumstances. Reanalysis of the data analysed by Bradshaw and colleagues shows that population density alone already explains up to 83% of the variation in reported flood occurrences, considerably more than forest cover or deforestation (o10%). Feasible explanations for this statistical finding -whether spurious or causative -are not difficult to conceive. We, therefore, consider the conclusion of Bradshaw and colleagues to be unsupported. However, their study is a valuable first step to show how these or similar flood data might be used to further explore the relationship between land cover and flooding.

The upland of Dartmoor, southwest England, is one of the flagship prehistoric landscapes within Britain owing to the excellent survival of extensive prehistoric coaxial field systems. Archaeological surveys and rescue excavations during the 1970s and 1980s did much to further the understanding of this landscape; however, much remains to be explored, in particular the chronology of enclosure, the nature of the pre-enclosure landscape and the relationship between Bronze Age communities and their environment. Reconsideration of this landscape is important, given the place it holds in our understanding of subdivision of the landscape across northwest Europe during prehistory. This paper presents new palaeoecological data recovered as part of an integrated archaeological and palaeoecological project on northeast Dartmoor. The sequences detailed here include the first dated Neolithic period palaeoenvironmental data from within the prehistoric enclosed land on the moor, providing a longerterm context for enclosure. Neolithic groups are implicated in the first establishment of heathland in the study area at around 3630e3370 cal BC. During the early Bronze Age, reestablishment of hazel scrub in the study area implies reduced use of the upland, although it is not clear whether this is local or indicative of the wider landscape. A combination of pollen and fungal spore data indicates a substantial shift to species-rich grassland with grazing animals at c.1480 cal BC in a phase that lasted 400 years. The later Bronze Age and early Iron Age are characterised by low intensity use of the upland. These data provide new chronological data for land cover change on Dartmoor and whilst they broadly confirm existing models of upland land use in later prehistory, their proximity to the standing archaeology affords a more nuanced interpretation of local change.

Kajian ini dijalankan untuk mengesan perubahan guna tanah dan litupan bumi di daerah Miri, Sarawak menggunakan pendekatan penderiaan jauh. Perbandingan guna tanah dan litupan bumi pada tahun 2001 hingga 2016 telah dilakukan bagi melihat perubahan guna tanah yang telah berlaku di daerah Miri. Data asas dalam mengesan perubahan guna dan litupan bumi ialah imej satelit Landsat (TM dan OLI-TIRS). Kawasan kajian telah diklasifikasikan kepada enam kategori guna tanah asas iaitu tepu bina, hutan darat, hutan gambut, tanah lapang, kelapa sawit dan air. Hasil perbandingan peta klasifikasi imej satelit Landsat pada tahun 2001 (TM) dan 2016 (OLI-TIRS) menunjukkan bahawa terdapat peningkatan yang ketara kawasan tepu bina dari 4.4% kepada 11.5% dan penanaman kelapa sawit dari 9.8% kepada 43.6% terutamanya di kawasan berhampiran dengan aktiviti pembandaran. Hutan darat mengalami kehilangan keluasan yang serius dari 42% kepada 47% dalam jangkamasa 15 tahun. Kesimpulanya pembangunan dan kemajuan dalam daerah Miri memberi tekanan kepada guna tanah hutan dan pengekalan hutan.

Abstract: The purpose of this study is to detect changes in land use and land cover in the area of Miri, Sarawak using remote sensing. Comparison land use and land cover from 2001 to 2016 was carried out to detect the changes in land use and land cover of Miri district. The basic data used for this change detection study are satellite images of Landsat (TM and OLI-TIRS). The study area was classified into six categories of land use i.e built up, inland forest, peat forest, cleared land, oil palm and water body. Comparison of the classified Landsat imagery in 2001 (TM) and 2016 (OLI-TIRS) shows that there is a significant increase of built-up areas from 4.4% to 11.5% and oil palm cultivation from 9.8% to 43.6%, especially near to urban areas. Inland forest suffered the worst declined from 42% to 47% within the 15 years. As conclusion, the development and advancement in the Miri district puts pressure on forest land and forest conservation.

A study was carried out at Karima Village in the Mwea Rice Irrigation Scheme in Kenya to assess the impact of rice husbandry and associated land cover change for mosquito larval abundance. A multi-temporal, land use land cover (LULC) classification dataset incorporating distributions of Anopheles arabiensis aquatic larval habitats was produced in ERDAS Imagine version 8.7 using combined images from IKONOS at 4m spatial resolution from 2005 and Landsat Thematic Mapper (TM)™ classification data at 30-meters spatial resolution from 1988 for Karima. Of 207 larval habitats sampled, most were either canals (53.4%) or paddies (45.9%), and only one habitat was classified as a seep (0.5%). The proportion of habitats that were poorly drained was 55.1% compared with 44.9% for the habitats that were well drained. An LULC base map was generated. A grid incorporating each rice paddy was overlaid over the LULC maps stratifying each cell based on levels of irrigation. Paddies/grid cells were classified as 1) well irrigated and 2) poorly irrigated. Early stages of rice growth showed peak larval production during the early part of the cropping cycle (rainy season). Total LULC change for Karima over 16 years was 59.8%. Of those areas in which change was detected, the LULC change for Karima was 4.30% for rice field to built environment, 8.74% for fallow to built environment, 7.19% for rice field to fallow, 19.03% built to fallow, 5.52% for fallow to rice field, and 8.35% for built environment to rice field. Of 207 aquatic habitats in Karima, 54.1 (n ‫ס‬ 112) were located in LULC change sites and 45.9 (n ‫ס‬ 95) were located in LULC non-change sites. Rice crop LULC maps derived from IKONOS and TM data in geographic information systems can be used to investigate the relationship between rice cultivation practices and higher anopheline larval habitat distribution.

The impacts of historical land cover changes witnessed between 1973 and 2000 on the hydrologic response of the Nyando River Basin were investigated. The land cover changes were obtained through consistent classifications of selected Landsat satellite images. Their effects on runoff peak discharges and volumes were subsequently assessed using selected hydrologic models for runoff generation and routing available within the HEC-HMS. Physically based parameters of the models were estimated from the land cover change maps together with a digital elevation model and soil datasets of the basin. Observed storm events for the simulation were selected and their interpolated spatial distributions obtained using the univariate ordinary Kriging procedure. The simulated flows from the 14 sub-catchments were routed downstream afterwards to obtain the accrued effects in the entire river basin. Model results obtained generally revealed significant and varying increases in the runoff peak discharges and volumes within the basin. In the upstream sub-catchments with higher rates of deforestation, increases between 30 and 47% were observed in the peak discharge. In the entire basin, however, the flood peak discharges and volumes increased by at least 16 and 10% respectively during the entire study period. The study successfully outlined the hydrological consequences of the eminent land cover changes and hence the need for sustainable land use and catchment management strategies.

Scientists need a better and larger set of tools to validate land-use change models, because it is essential to know a model's prediction accuracy. This paper describes how to use the relative operating characteristic (ROC) as a quantitative measurement to validate a land-cover change model. Typically, a crucial component of a spatially explicit simulation model of land-cover change is a map of suitability for land-cover change, for example a map of probability of deforestation. The model usually selects locations for new land-cover change at locations that have relatively high suitability. The ROC can compare a map of actual change to maps of modeled suitability for land-cover change. ROC is a summary statistic derived from several two-by-two contingency tables, where each contingency table corresponds to a different simulated scenario of future land-cover change. The categories in each contingency table are actual change and actual non-change versus simulated change and simulated non-change. This paper applies the theoretical concepts to a model of deforestation in the Ipswich watershed, USA.

Urban areas are important social, economic, political and industrial centers. Rapid urban growth in Africa is creating seriou s economic, social and environmentalchallenges. Apar t from determining the rate of urban growth, previous studies on urban land cover change inYola North Local Government Area did not address the relationship between urban growth, economic and development indices like per capita Gross Domestic Product (GDP) and Human Development Indices (HDI). This study is imed at analyzingurban growth rate over a 28 year period (1988-2016).The study used 3 Landsat satellite image scenes (1988, 2002 and 2016), urban growth pattern, economic, and human development indices. The satellite imagery were classified using the maximum likelihood algorithm in QGIS software. Simple descriptive statistics was used to analyze changes in urban area over the separate period and then compared with annual data on per capita GDP and HDI. Landscape expansion index was used to determine the urban growth pattern.Result show that urban land cover increased from one tenth of the total land area in 1988 to one fourth of the land area in 2016. Periphery (edge) expansionis the dominant pattern of urban growth during this period. Simple comparison between urban growth rate, per capita GDP and HDI indicates a sharp contrast between the former two and the later. Many newly developed areas lack basic infrastructure such as roads, pipe borne water and drainages. Based on the findings, it was concluded that urban growth in the study area is unsustainable since increase in per capita GDP does not translate to increase in HDI and the provision of basic infrastructure. These economic and human development indices might have contributed to the pattern of urban growth in the form of edge expansion identified in this study. It is recommended that authorities should invest more on urban infrastructure and the promotion of outlying pattern of urban development.

The extent of tropical wetlands, the magnitude of loss, and the related socioeconomic ramifications of the destruction of Indonesian wetlands are of global significance. The carbon density and rates of land-cover change in these ecosystems are amongst the highest of any forest type on Earth. Therefore, addressing interrelated issues of climate change and land use could be valuable in generating new options on how mangroves and peatlands should be best managed. This paper is produced by bringing together Indonesian and international scientists from diverse backgrounds and with diverse experiences in both freshwater and coastal tropical wetlands. It describes the state of the science, significant research needs, and potential transdisciplinary approaches necessary to implement climate change adaptation and mitigation strategies.

Impacts of climate and land cover changes on streamflow were assessed using a hydrological modeling. The precipitation runoff modeling system of the US Geological Survey was modified in order to consider wetlands as a separate hydrological response unit. Initial model parameters were obtained from a previously modeled adjacent catchment and subsequent calibration and validation were carried out. The model calibration and validation periods were divided into three. The calibration period was a five years period (1981)(1982)(1983)(1984)(1985)(1986). The validation period was divided into two: validation 1 (1986-1991) and validation 2 (1996)(1997)(1998)(1999)(2000)(2001)(2002). Model performance was evaluated by using joint plots of daily and monthly observed and simulated runoff hydrographs and different coefficients of efficiency. The model coefficients of efficiency were 0.71 for the calibration period and 0.69 and 0.66 for validation periods 1 and 2, respectively. A "delta-change" method was used to formulate climatic scenarios. One land cover change scenario was also used to assess the likely impacts of these changes on the runoff. The results of the scenario analysis showed that the basin is more sensitive to increase in rainfall (+80% for +20%) than to a decrease (−62% for −20%). The rainfall elasticity is 4:1 for a 20% increase in rainfall while it is 3:1 for a 20% reduction. A 1.5 • c increase in temperature resulted in a 6% increase in potential evapotranspiration and 13% decrease in streamflow. This indicates that the watershed is more elastic to rainfall increase than temperature. The proposed land cover scenario of converting areas between 2000 to 3000 m a.s.l. to woodland also resulted in a significant decrease in streamflow (11.8%). The study showed that properly calibrated and validated models could help understand likely impacts of climate and land cover changes on catchment water balance.

Combustion of coal, oil, and natural gas, and to a lesser extent deforestation, land-cover change, and emissions of halocarbons and other greenhouse gases, are rapidly increasing the atmospheric concentrations of climate-warming gases. The warming of approximately 0.1-0.2°C per decade that has resulted is very likely the primary cause of the increasing loss of snow cover and Arctic sea ice, of more frequent occurrence of very heavy precipitation, of rising sea level, and of shifts in the natural ranges of plants and animals. The global average temperature is already approximately 0.8°C above its preindustrial level, and present atmospheric levels of greenhouse gases will contribute to further warming of 0.5-1°C as equilibrium is re-established. Warming has been and will be greater in mid and high latitudes compared with low latitudes, over land compared with oceans, and at night compared with day. As emissions continue to increase, both warming and the commitment to future warming are presently increasing at a rate of approximately 0.2°C per decade, with projections that the rate of warming will further increase if emission controls are not put in place. Such warming and the associated changes are likely to result in severe impacts on key societal and environmental support systems. Present estimates are that limiting the increase in global average surface temperature to no more than 2-2.5°C above its 1750 value of approximately 15°C will be required to avoid the most catastrophic, but certainly not all, consequences of climate change. Accomplishing this will require reducing emissions sharply by 2050 and to near zero by 2100. This can only be achieved if: