# Review of Land Surface Albedo: Variance Characteristics, Climate Effect and Management Strategy
## 4 Climate Feedback and Management Strategy for Surface Albedo
### Economic Cost and Management Strategy for Surface Albedo
Different from the traditional view that wood fuels are carbon neutral,similar to other bioenergy sources, and considering the offset of CO2 sequestration by biomass regrowth to CO2 release, quantified studies over a 100-year time horizon show that bioenergy from slow-growing forests usually has a greater global warming potential (GWP) than fossil oil and gas, while the results associated with coal are condition-dependent [229]. Biofuel crops are considered useful climate benefits due to land conversions, and the LCA analysis shows a small cooling effect (e.g., corn ethanol, \(-1.8\) g CO2-eq) and a stronger (e.g., switchgrass ethanol, \(12.1\) g CO2-eq) and smaller warming effect (e.g., miscanthus ethanol, \(2.7\) g CO2-eq) [106]. However, a different conclusion was found that an albedo-induced climate mitigation for perennial (e.g., switchgrass) but not annual (e.g., corn) bioenergy crops shows a much greater cooling effect [230]. Moreover, many management methods have been proposed to control the surface albedo of water cycle process factors for snow, ice and water to mitigate global climate warming. Vehicle emissions in the surroundings of ski resorts can reduce snowwhitness and accelerate snowmelt, which affects attractiveness for visitors; therefore, traffic restrictions may allow for more stable snowpack and regional climate conditions [231]. The positive SLAF in the Arctic has amplified warming, which has driven further melting, and thus, reducing model errors in the current seasonal climate feedback and ice thickness can narrow its spread under climate change [32]. The increasing global temperature not only results in the melting of the Greenland ice sheet but also in albedo loss and in turn reduces the strength of SAF and increases the social cost of carbon [232]. For low-albedo water, one feasible method is to brighten the surface of the ocean by increasing the albedo and areal extent of bubbles in existing shipping wakes, and simulations show that the addition of surfactant is required to extend the wake lifetime from minutes to days and months to achieve a significant negative global radiative forcing [136]. Geoengineering on the ocean surface albedo scheme was performed based on a series of Earth system models and shows that the maintenance of the TOA net radiation constant is not sufficient for preventing changes in global mean temperature [19]. Lower albedo in the water of hydropower reservoirs than in terrestrial landscapes results in a positive radiative forcing and offsets some of the negative radiative forcing of hydroelectricity generation; in the future, hydropower plants need to minimize the albedo penalty to make a meaningful contribution towards limiting global warming [137]. In city management, albedo mitigation strategies are widely used, and square urban grids show more potential to reduce the average hourly temperature by using fewer mitigated points [233]. An LCA of different roofs shows that high surface albedo plays a crucial role in offsetting radiative forcings with a decrease in CO2 equivalents and mitigation of the UHI; a highly reflective roof can also save annual cooling energy use relative to a low-albedo roof [234]. A new type of RRM has been developed as a building coating to help counter UHIs, and building surfaces with RRMs are more effective than other materials with diffuse or mirror reflective characteristics [143]. However, precautions need to be exercised by city planners and policy makers pursuing the large-scale deployment of reflective materials without a sufficient understanding of their environmental impacts, especially on regional hydroclimates, and the optimal strategy for UHIs needs to be determined on a city-by-city basis rather than with a \"one-solution-fits-all\" approach [25].