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Global Climate Forcing from Albedo Change Caused by Large-scale Deforestation and Reforestation: Quantification and Attribution of Geographic VariationLarge-scale deforestation and reforestation have contributed substantially to historical and contemporary global climate change in part through albedo-induced radiative forcing, with meaningful implications for forest management aiming to mitigate climate change. Associated warming or cooling varies widely across the globe due to a range of factors including forest type, snow cover, and insolation, but resulting geographic variation remain spoorly described and has been largely based on model assessments. This study provides an observation-based approach to quantify local and global radiative forcings from large-scale deforestation and reforestation and further examines mechanisms that result in the spatial heterogeneity of radiative forcing. We incorporate a new spatially and temporally explicit land cover-specific albedo product derived from Moderate Resolution Imaging Spectroradiometer with a historical land use data set (Land Use Harmonization product). Spatial variation in radiative forcing was attributed to four mechanisms, including the change in snow-covered albedo, change in snow-free albedo, snow cover fraction, and incoming solar radiation. We find an albedo-only radiative forcing (RF) of -0.819 W m(exp -2) if year 2000 forests were completely deforested and converted to croplands. Albedo RF from global reforestation of present-day croplands to recover year 1700 forests is estimated to be 0.161 W m)exp -2). Snow-cover fraction is identified as the primary factor in determining the spatial variation of radiative forcing in winter, while the magnitude of the change in snow-free albedo is the primary factor determining variations in summertime RF. Findings reinforce the notion that, for conifers at the snowier high latitudes, albedo RF diminishes the warming from forest loss and the cooling from forest gain more so than for other forest types, latitudes, and climate settings.
Document ID
20170007801
Document Type
Reprint (Version printed in journal)
Authors
Jiao, Tong (Clark Univ. Worcester, MA, United States)
Williams, Christopher A. (Clark Univ. Worcester, MA, United States)
Ghimire, Bardan (Clark Univ. Worcester, MA, United States)
Masek, Jeffrey (NASA Goddard Space Flight Center Greenbelt, MD United States)
Gao, Feng (Agricultural Research Service Beltsville, MD, United States)
Schaaf, Crystal (Massachusetts Univ. Boston, MA, United States)
Date Acquired
August 17, 2017
Publication Date
April 21, 2017
Publication Information
Publication: Climatic Change
Volume: 142
Issue: 4-Mar
ISSN: 0165-0009
Subject Category
Meteorology and Climatology
Report/Patent Number
GSFC-E-DAA-TN45898
GSFC-E-DAA-TN56676
Funding Number(s)
CONTRACT_GRANT: NNX14AI73G
CONTRACT_GRANT: NNX11AG53G
Distribution Limits
Public
Copyright
Other