# Review of Land Surface Albedo: Variance Characteristics, Climate Effect and Management Strategy
## 4 Climate Feedback and Management Strategy for Surface Albedo
### Monitoring Short-to-Long-Term Albedo Change and Climate Effects
#### 4.1.2 Albedo Variances Induced by Anthropogenic Land Use  
Recently, increasing attention has been dedicated to human-induced albedo variances, and cultivation and urbanization are considered the two main factors involved [182]. For some deforested areas of the Amazon, secondary vegetation has been the dominant land cover with similar albedo levels as those of primary forests [183]. As an important source of transportation biofuel, increased forest harvesting was adopted with higher albedo and induced varying radiative forcing over time [184]. To achieve ecological goals, such as water and soil conservation and sand prevention, artificial afforestation has been widely implemented worldwide and can significantly increase carbon storage by absorbing atmospheric carbon dioxide and thus decreasing radiative forcing to cool the Earth [158]. However, surface changes from more reflective pasture to relatively less reflective forest cover can lead to a positive radiative forcing [158,185], and an overall decrease in the benefits from increased carbon storage by 17-24% was found in New Zealand [158]. In particular, the positive forcing arising from surface change from winter snow to forest in high-latitude regions may even offset the negative forcing from carbon sequestration [43,60], and an empirically-based projection made in Norway also suggests that the positive climate feedback of high-latitude and high-elevation expanding forests with seasonal snow cover exceeds that of afforestation at lower elevations in the 21 st century [43]. High-albedo soils denuded by overgrazing appear much brighter and cooler than regions covered by natural vegetation under sunlit conditions, which results in a thermal depression effect and can further lead to regional climatic desertification [160]. Therefore, reindeer summer grazing greatly decreases shrub height, abundance and total biomass in pastures, which present increasing albedo and eventually delay snowmelt [186]. In terms of agriculture, anthropogenic vegetation changes have caused relatively weak global mean radiative forcing (\(-\)0.09 W/m\({}^{2}\)) from preagricultural times to the present, but regional radiative forcing is strong in certain regions and may have resulted in regional climate changes [187]. The significant transformation from forest to cropland in China between 850 and 2015 was investigated using the historical land-use harmonization dataset and albedo look-upmaps, which shows an annual-mean increase (i.e., 0.00110) in land surface albedo and brings a slight negative radiative forcing of \(-\)0.09 \(\pm\) 0.04 W/m\({}^{2}\)[188]. A study shows that present land-use transitions over China bring cooler summers and winters accompanied by reduced diurnal temperature ranges, and region-oriented parameterization should be applied to consider the heterogeneous biophysical effects of vegetation in different climate zones [189]. Urban construction is a major process in terms of human activity, which results in a totally slower increase in surface albedo due to transitions from canopy covers to darker impervious covers (e.g., roof and pavement) [190; 191]. Thus, UHIs were first discovered in the early 1800s, which emerges as the source of many urban environmental problems and exacerbates the living environment in cities, and reflective materials are expected to help tackle these challenges [25]. The LCA of urban roofs shows that high-albedo materials can effectively mitigate UHIs [192]. Moreover, the LCA of pavement albedo has a varying impact on the carbon budget along with materials, where Portland cement concrete pavement reduces CO\({}_{2}\)-equivalent emissions by 9.2%, and an increase of 19.1% was observed for hot mixture asphalt pavement [193]. Computational fluid dynamics (CFD) analyses of asphalt and concrete pavements under the same ambient conditions show that asphalt surface temperatures are consistently higher, and surface temperatures decrease with increasing surface albedo and thermal inertia values for the two materials, especially for surface albedo [194].