scholarly journals Climatic Impact of Global-Scale Deforestation: Radiative versus Nonradiative Processes

2010 ◽  
Vol 23 (1) ◽  
pp. 97-112 ◽  
Author(s):  
Edouard L. Davin ◽  
Nathalie de Noblet-Ducoudré
Keyword(s):  
Surface Roughness ◽  
Land Cover ◽  
Land Cover Change ◽  
Radiative Forcing ◽  
Surface Albedo ◽  
Global Scale ◽  
Ocean Coupling ◽  
Albedo Effect ◽  
Change Impact ◽  
Nonradiative Processes

Abstract A fully coupled land–ocean–atmosphere GCM is used to explore the biogeophysical impact of large-scale deforestation on surface climate. By analyzing the model sensitivity to global-scale replacement of forests by grassland, it is shown that the surface albedo increase owing to deforestation has a cooling effect of −1.36 K globally. On the other hand, forest removal decreases evapotranspiration efficiency and decreases surface roughness, both leading to a global surface warming of 0.24 and 0.29 K, respectively. The net biogeophysical impact of deforestation results from the competition between these effects. Globally, the albedo effect is dominant because of its wider-scale impact, and the net biogeophysical impact of deforestation is thus a cooling of −1 K. Over land, the balance between the different processes varies with latitude. In temperate and boreal zones of the Northern Hemisphere the albedo effect is stronger and deforestation thus induces a cooling. Conversely, in the tropics the net impact of deforestation is a warming, because evapotranspiration efficiency and surface roughness provide the dominant influence. The authors also explore the importance of the ocean coupling in shaping the climate response to deforestation. First, the temperature over ocean responds to the land cover perturbation. Second, even the temperature change over land is greatly affected by the ocean coupling. By assuming fixed oceanic conditions, the net effect of deforestation, averaged over all land areas, is a warming, whereas taking into account the coupling with the ocean leads, on the contrary, to a net land cooling. Furthermore, it is shown that the main parameter involved in the coupling with the ocean is surface albedo. Indeed, a change in albedo modifies temperature and humidity in the whole troposphere, thus enabling the initially land-confined perturbation to be transferred to the ocean. Finally, the radiative forcing framework is discussed in the context of land cover change impact on climate. The experiments herein illustrate that deforestation triggers two opposite types of forcing mechanisms—radiative forcing (owing to surface albedo change) and nonradiative forcing (owing to change in evapotranspiration efficiency and surface roughness)—that exhibit a similar magnitude globally. However, when applying the radiative forcing concept, nonradiative processes are ignored, which may lead to a misrepresentation of land cover change impact on climate.

Hydrological regime, water availability and land use/land cover change impact on the water balance in a large agriculture basin in the Southern Brazilian Amazon

2021 ◽  
Vol 108 ◽  
pp. 103224
Author(s):  
Tárcio Rocha Lopes ◽  
Cornélio Alberto Zolin ◽  
Rafael Mingoti ◽  
Laurimar Gonçalves Vendrusculo ◽  
Frederico Terra de Almeida ◽  
...  
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Water Balance ◽  
Land Cover Change ◽  
Water Availability ◽  
Hydrological Regime ◽  
Brazilian Amazon ◽  
Land Use Land Cover ◽  
Change Impact

The SYPR Integrative Assessment Model: Complexity in Development

2004 ◽  
Author(s):  
Steven Manson
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Environmental Change ◽  
Land Cover Change ◽  
Integrated Assessment ◽  
Global Environmental Change ◽  
Global Scale ◽  
Assessment Model ◽  
Integrated Assessment Modeling ◽  
Global Environmental

Be it global environmental change or environment and development, landuse and land-cover change is central to the dynamics and consequences in question in the southern Yucatán peninsular region. Designing policies to address these impacts is hampered by the difficulty of projecting land use and land cover, not only because the dynamics are complex but also because consequences are strongly place-based. This chapter describes an integrated assessment modeling framework that builds on the research detailed in earlier chapters in order to project land-use and land-cover change in a geographically explicit way. Integrated assessment is a term that describes holistic treatments of complex problems to assess both science and policy endeavors in global environmental change (Rotmans and Dowlatabadi 1998). The most common form of integrated assessment is computer modeling that combines socioeconomic and biogeophysical factors to predict global climate. Advanced in part by the successes of these global-scale models, integrated assessment has expanded to structure knowledge and set research priorities for a large range of coupled human–environment problems. Increasing recognition is given to the need for integrated assessment models to address regionalscale problems that are masked by global-scale assessments (Walker 1994). Such models must address two issues to project successfully land-use and land-cover change at the regional scale. First, change occurs incrementally in spatially distinct patterns that have different implications for global change (Lambin 1994). Second, a model must account for the complexity of, and relationships among, socio-economic and environmental factors (B. L. Turner et al. 1995). The SYPR integrated assessment model, therefore, has a fine temporal and spatial grain and it places land-use and landcover change at the intersection of land-manager decision-making, the environment, and socio-economic institutions. What follows is a description of an ongoing integrated assessment modeling endeavor of the SYPR project (henceforth, SYPR IA model). The depth and breadth of the SYPR project poses a challenge to the integrated assessment modeling effort since some unifying framework must reconcile a broad array of issues, theories, and data. The global change research community offers a general conception of how environmental change results from infrastructure development, population pressure, market opportunities, resource institutions, and environmental or resource policies (Stern, Young, and Drukman 1992).

scholarly journals A spatial resolution threshold of land cover in estimating terrestrial carbon sequestration in four counties in Georgia and Alabama, USA

2010 ◽  
Vol 7 (1) ◽  
pp. 71-80 ◽  
Author(s):  
S. Q. Zhao ◽  
S. Liu ◽  
Z. Li ◽  
T. L. Sohl
Keyword(s):  
Carbon Sequestration ◽  
Land Cover ◽  
Land Cover Change ◽  
Spatial Resolution ◽  
Spatial Patterns ◽  
Global Scale ◽  
Terrestrial Carbon ◽  
Carbon Modeling ◽  
Terrestrial Carbon Sequestration ◽  
The Impact

Abstract. Changes in carbon density (i.e., carbon stock per unit area) and land cover greatly affect carbon sequestration. Previous studies have shown that land cover change detection strongly depends on spatial scale. However, the influence of the spatial resolution of land cover change information on the estimated terrestrial carbon sequestration is not known. Here, we quantified and evaluated the impact of land cover change databases at various spatial resolutions (250 m, 500 m, 1 km, 2 km, and 4 km) on the magnitude and spatial patterns of regional carbon sequestration in four counties in Georgia and Alabama using the General Ensemble biogeochemical Modeling System (GEMS). Results indicated a threshold of 1 km in the land cover change databases and in the estimated regional terrestrial carbon sequestration. Beyond this threshold, significant biases occurred in the estimation of terrestrial carbon sequestration, its interannual variability, and spatial patterns. In addition, the overriding impact of interannual climate variability on the temporal change of regional carbon sequestration was unrealistically overshadowed by the impact of land cover change beyond the threshold. The implications of these findings directly challenge current continental- to global-scale carbon modeling efforts relying on information at coarse spatial resolution without incorporating fine-scale land cover dynamics.

scholarly journals Spatiotemporal Variability of Land Surface Albedo over the Tibet Plateau from 2001 to 2019

2020 ◽  
Vol 12 (7) ◽  
pp. 1188
Author(s):  
Xingwen Lin ◽  
Jianguang Wen ◽  
Qinhuo Liu ◽  
Dongqin You ◽  
Shengbiao Wu ◽  
...  
Keyword(s):  
Climate Change ◽  
Time Series ◽  
Land Cover ◽  
Snow Cover ◽  
Land Surface ◽  
Radiative Forcing ◽  
Surface Albedo ◽  
Tibet Plateau ◽  
Land Cover Types ◽  
Yearly Average

As an essential climate variable (ECV), land surface albedo plays an important role in the Earth surface radiation budget and regional or global climate change. The Tibetan Plateau (TP) is a sensitive environment to climate change, and understanding its albedo seasonal and inter-annual variations is thus important to help capture the climate change rules. In this paper, we analyzed the large-scale spatial patterns, temporal trends, and seasonal variability of land surface albedo overall the TP, based on the moderate resolution imaging spectroradiometer (MODIS) MCD43 albedo products from 2001 to 2019. Specifically, we assessed the correlations between the albedo anomaly and the anomalies of normalized difference vegetation index (NDVI), the fraction of snow cover (snow cover), and land surface temperature (LST). The results show that there are larger albedo variations distributed in the mountainous terrain of the TP. Approximately 10.06% of the land surface is identified to have been influenced by the significant albedo variation from the year 2001 to 2019. The yearly averaged albedo was decreased significantly at a rate of 0.0007 (Sen’s slope) over the TP. Additionally, the yearly average snow cover was decreased at a rate of 0.0756. However, the yearly average NDVI and LST were increased with slopes of 0.0004 and 0.0253 over the TP, respectively. The relative radiative forcing (RRF) caused by the land cover change (LCC) is larger than that caused by gradual albedo variation in steady land cover types. Overall, the RRF due to gradual albedo variation varied from 0.0005 to 0.0170 W/m2, and the RRF due to LCC variation varied from 0.0037 to 0.0243 W/m2 during the years 2001 to 2019. The positive RRF caused by gradual albedo variation or the LCC can strengthen the warming effects in the TP. The impact of the gradual albedo variations occurring in the steady land cover types was very low between 2001 and 2019 because the time series was short, and it therefore cannot be neglected when examining radiative forcing for a long time series regarding climate change.

scholarly journals At what scales do climate variability and land cover change impact on flooding and low flows?

2007 ◽  
Vol 21 (9) ◽  
pp. 1241-1247 ◽  
Author(s):  
Günter Blöschl ◽  
Sandra Ardoin-Bardin ◽  
Mike Bonell ◽  
Manfred Dorninger ◽  
David Goodrich ◽  
...  
Keyword(s):  
Land Cover ◽  
Climate Variability ◽  
Land Cover Change ◽  
Low Flows ◽  
Change Impact

scholarly journals Effects of Surface Albedo on Cloud and Radiation Processes in Cloud-Resolving Model Simulations

2010 ◽  
Vol 67 (5) ◽  
pp. 1474-1491 ◽  
Author(s):  
Sunwook Park ◽  
Xiaoqing Wu
Keyword(s):  
Radiative Forcing ◽  
Surface Albedo ◽  
Critical Value ◽  
Cloud Base ◽  
Radiative Fluxes ◽  
Cloud Properties ◽  
Cloud Resolving Model ◽  
Albedo Effect ◽  
Evolving Surface ◽  
Radiation Processes

Abstract The relationship among the surface albedo, cloud properties, and radiative fluxes is investigated for the first time using a year-long cloud-resolving model (CRM) simulation with the prescribed evolving surface albedo. In comparison with the run using a fixed surface albedo, the CRM with the observed surface albedo represents the shortwave radiative budget closer to the observations in the winter. The greater surface albedo induces weaker instability in the low troposphere so that the amount of low clouds decreases during the winter. This reduces the shortwave and longwave cloud radiative forcing at the surface. The analysis of the CRM simulations with the evolving surface albedo reveals that there is a critical value (0.35) of the surface albedo. For albedos greater than the critical value, the upward shortwave flux at the top of the atmosphere (TOA) is positively proportional to the surface albedos when optically thin clouds exist, and is not much affected by reflection on the cloud top. If optically thick clouds occur and the surface albedo is greater than the critical value, the upward shortwave flux at the TOA is significantly influenced by the reflection of cloud top, but not much affected by the surface albedo. In addition, for albedos larger than the critical value, the downward shortwave flux at the surface is primarily influenced by the surface albedo and the reflection from the cloud base if optically thick clouds occur. However, the downward shortwave flux at the surface is not significantly affected by the surface albedo when optically thin clouds exist because the reflection on the cloud base is weak. When surface albedos are less than the critical value, those relationships among surface albedo, shortwave flux, and cloud properties are not obvious. The surface albedo effect on shortwave flux increases as solar zenith angle (SZA) decreases, but its dependence on the SZA is negligible when optically thick clouds exist.

scholarly journals Impact of land cover change on surface climate: Relevance of the radiative forcing concept

2007 ◽  
Vol 34 (13) ◽  
pp. n/a-n/a ◽  
Author(s):  
E. L. Davin ◽  
N. de Noblet-Ducoudré ◽  
P. Friedlingstein
Keyword(s):  
Land Cover ◽  
Land Cover Change ◽  
Radiative Forcing ◽  
Surface Climate

scholarly journals Land Cover Change Intensifies Actual and Potential Radiative Forcing through CO2 in South and Southeast Asia from 1992 to 2015

2019 ◽  
Vol 16 (14) ◽  
pp. 2460 ◽  
Author(s):  
Yaoping Cui ◽  
Michael E Meadows ◽  
Nan Li ◽  
Yiming Fu ◽  
Guosong Zhao ◽  
...  
Keyword(s):  
Land Cover ◽  
Southeast Asia ◽  
Land Cover Change ◽  
Radiative Forcing ◽  
Co2 Sequestration ◽  
Large Scale ◽  
Land Reclamation ◽  
Urban Expansion ◽  
Co2 Flux ◽  
South And Southeast Asia

Land cover change (LCC) and its impact on CO2 sequestration and radiative forcing (RF) could dramatically affect climate change, but there has been little effort to address this issue in South and Southeast Asia over a long period of time using actual land cover information. In this study, annual land cover data from 1992 to 2015 were used to assess the CO2 flux and corresponding RF due to LCC in South and Southeast Asia. The results showed that 553.2 × 103 km2 of the region experienced LCC during this period, mostly due to land reclamation, urban expansion, and deforestation. These LCC caused a marked net decrease in net ecosystem productivity (NEP) as a composite of the various land cover categories during the whole study period, especially since 2001. The CO2 sequestration was 2160 TgCO2 during the early 1990s however cumulative sequestration decreased by 414.95 TgCO2 by 2015. Correspondingly, the cooling effect of NEP, i.e. the total actual RF, was −0.366 W m−2 in South and Southeast Asia between 1992 and 2015. However, the potential RF of the cumulatively reduced NEP due to LCC relative to the 1990s resulted in a warming effect of 2.33 × 10−3 W m−2 in 2015. Our study provides an applicable framework to accurately assess the potential effect of large-scale LCC on climate.

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