Land change, fire, and climate weaken carbon sink in the conterminous United States
| Authors: | Jinxun Liu, Benjamin M. Sleeter, Zhiliang Zhu, Mark A. Cochrane, Qiang Zhou, Bin Wang, Grant M. Domke, Paul C. Selmants, Lisamarie Windham-Myers, Qiuan Zhu, Tamara S. Wilson, Kristin B. Byrd, Eric J. Ward, Terry L Sohl, Todd J. Hawbaker, Zhen Zhang, Christopher E. Soulard, Kimberly P. Wickland, Robert G. Striegl |
| Year: | 2025 |
| Type: | Scientific Journal |
| Station: | Northern Research Station |
| DOI: | https://doi.org/10.1126/sciadv.adx7823 |
| Source: | Science Advances |
Abstract
The land carbon sink of the conterminous United States was evaluated using a bottom-upmodeling framework and 30-meter land change data from 1985 to 2020. This cross-scale,cross-landscape, and cross-system approach tracked fractional land cover changes and applied regional model calibration. Results show average terrestrial and aquatic carbon sinks of +110 ± 37 and +19 ± 0.5 teragrams of carbon per year, respectively. The terrestrialcarbon sink, showing no clear trend, peaked in the 1990s, with more years as a carbon source since 2000, contradicting recent national and global studies. Land change had the largest impact (−70 ± 5.5 teragrams of carbon per year), exceeding impacts of climate (−33 ± 48 teragrams of carbon per year), wildfire (−7.7 ± 2.4 teragrams of carbon per year), and erosion transport (−1.9 ± 0.13 teragrams of carbon per year). The positive CO2 fertilizationeffect (+69 ± 12 teragrams of carbon per year) was insufficient to maintain the carbon sink strength. Our framework reveals key paths of carbon loss, with implications for carbon budget and energy policies in the United States and beyond.