Empirical estimates of regional carbon budgets imply reduced global soil heterotrophic respiration

• 来源期刊: 国家科学评论（英文版）
• 年，卷（期）: 2021,（2）
• 所属期刊栏目: RESEARCH ARTICLES
• 页码范围: 55-68
• 页数: 14页
• 语种: 英文
• DOI: 10.1093/nsr/nwaa145

摘要

Resolving regional carbon budgets is critical for informing land-based mitigation policy.For nine regions covering nearly the whole globe,we collected inventory estimates of carbon-stock changes complemented by satellite estimates ofbiomass changes where inventory data are missing.The net land-atmospheric carbon exchange(NEE)was calculated by taking the sum of the carbon-stock change and lateral carbon fluxes from crop and wood trade,and riverine-carbon export to the ocean.Summing up NEE from all regions,we obtained a global'bottom-up'NEE for net land anthropogenic CO2 uptake of-2.2 ± 0.6 PgC yr-1 consistent with the independent top-down NEE from the global atmospheric carbon budget during 2000-2009.This estimate is so far the most comprehensive global bottom-up carbon budget accounting,which set up an important milestone for global carbon-cycle studies.By decomposing NEE into component fluxes,we found that global soil heterotrophic respiration amounts to a source of CO2 of 39 PgC yr-1 with an interquartile of 33-46 PgC yr-1—a much smaller portion of net primary productivity than previously reported.