Albedo-induced global warming potential following disturbances in global temperate and boreal forests

Authors: ZHU, Q. - Beijing Normal University; CHEN, J. - Michigan State University; CHARLES P-A, B. - University Of New Brunswick; SONNENTAG, O. - University Of Montreal; MONTAGNANI, L. - Free University Of Bozen-Bolzano; O’HALLORAN, T.L. - Clemson University; Scott, Russell - Russ; FORSYTHE, J. - Clemson University; SONG, B - Clemson University; ZOU, H. - Beijing Normal University; DUAN, M. - Beijing Normal University; LI, X. - Beijing Normal University

Submitted to: Journal of Geophysical Research-Biogeosciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/27/2024
Publication Date: 3/12/2024
Citation: Zhu, Q., Chen, J., Charles P-A, B., Sonnentag, O., Montagnani, L., O’Halloran, T., Scott, R.L., Forsythe, J., Song, B., Zou, H., Duan, M., Li, X. 2024. Albedo-induced global warming potential following disturbances in global temperate and boreal forests. Journal of Geophysical Research-Biogeosciences. 129(3). Article e2023JG007848. https://doi.org/10.1029/2023JG007848.
DOI: https://doi.org/10.1029/2023JG007848

Interpretive Summary: After forest disturbances, the removal of dense canopies exposes brighter surfaces, leading to higher surface albedo. can have different climate impacts than greenhouse gases emissions like CO2. In this study, we used observations to model how albedo changes over time following forest disturbances. We also assessed the climate impacts of these albedo changes, taking into account how albedo changes in time. Our results show that the age of the forest is the most significant factor influencing albedo after disturbances. However, the trajectory of albedo dynamics also depends on the forest types and disturbance types. We found that the elevated albedo in forests after disturbances accounts for substantial cooling effects in the first twenty years that is comparable to the effect of changes in net carbon uptake. Understanding the dynamic of albedo following forest disturbances is essential for quantifying the climate impacts, especially as more forests are experiencing disturbances induced by human activities.

Technical Abstract: Forest disturbances can result in very different canopies that carry elevated albedo, thus causing substantial cooling effects on the climate. Unfortunately, the resulting dynamic global warming potential from altered albedo (GWP'a) is poorly understood. We examined and modeled the changes in albedo over time after disturbances (i.e., forest age) by forest type, disturbance type and geographic location using direct measurements from 107 sites in temperate and boreal regions. Albedo in undisturbed forests was used as the reference to calculate albedo changes ('a) and GWP'a after a disturbance. We found that age is a significant factor for predicting albedo amid the obvious regulations from forest type and geographic locations. We found the strongest cooling GWP'a in the first 10 years after a disturbance, but it decreased rapidly with time. The changes in GWP'a were very different from the chronosequence of net ecosystem production (NEP). In the first decade after disturbances, GWP'a was negative (i.e., cooling) and surprisingly larger in magnitude, with an average of -0.609 kg CO2 m-2 yr-1, compared to NEP of -0.166 kg CO2 m-2 yr-1. Albedo continued to decrease and approached pre-disturbance levels until around 50 years, resulting in a nearly-zero GWP'a. This research illustrates that many forests in temperate and boreal regions can be considered significant cooling agents by taking into account the high albedo of young forests following disturbances.