Quantifying Albedo and Surface Temperature over Different Land Covers: Implications for Carbon Offsets

Abstract

Many organizations, both internationally and within the United States, have invested in forest sequestration projects to offset their carbon emissions. However, changes in albedo and surface temperature due to reforestation and afforestation projects may have unintended regional and global climate consequences. The objective of this study was to quantify the change of surface albedo and temperature across different land covers over the eastern United States using Landsat 7 ETM+ satellite images. A second objective was to evaluate the results in the context of potential net climate effects of reforestation and afforestation and their implications on carbon offsets. Most land covers were found to differ in their shortwave albedo and surface temperature. Specifically, open land (cropland and grassland) had a higher shortwave albedo and surface temperature compared to forests. Albedo and temperature also differed seasonally and with latitude for the same land cover type, suggesting that other factors influence local energy balance and climate. The shortwave albedo results are consistent with previous studies, but this study is one of only a few that examined both albedo and surface temperature for many different land cover types. Additional research is needed to quantify all of the physical and environmental factors affecting local and regional climate over different land covers, how these factors relate to each other, and how they will change through time due with carbon offset projects. In this way the true value of carbon mitigation tools can be predicted.