Forest canopy decline under elevated CO2 during the Paleocene-Eocene Thermal Maximum

• 成果类型: Article
• 署名作者: Dunn, Regan E.; Dechesne, Marieke; Foreman, Brady Z.; Nace, Keifer; West, Jenna M.; Currano, Ellen D.
• 署名单位: United States Department of the Interior; United States Geological Survey; Western Washington University; Whitman College; University of Wyoming
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-8075; 1095-9203
• DOI: 10.1126/science.aec4776
• 发表日期: 2026-08-13
• 页码: 696-701
• 关键词: carbon-isotope excursion; bighorn basin; AREA INDEX; RIPARIAN VEGETATION; organic-carbon; CLIMATE-CHANGE; stable carbon; BOUNDARY; terrestrial; constraints

摘要

Uncertainty remains regarding the impact of rapid anthropogenic warming on forest ecosystem structure, biodiversity, and function. As an analog, we reconstruct forest canopy density and compositional change in Wyoming, USA, through the Paleocene-Eocene Thermal Maximum (PETM), an interval of abrupt carbon increase and warming similar to 56 million years ago. We develop a proxy to quantify leaf area index and assess shifts in floral composition using palynomorphs. Forest canopies opened abruptly at onset of PETM warming, landscape erosion increased, and vegetation shifted from broad-leaved angiosperm to fern- and palm-dominated ecosystems. When combined with regional data, these patterns suggest that continental-scale changes in plant communities cause landscape destabilization. These shifts also have implications for multimillennial-scale hydrologic and carbon cycle feedbacks in the climate system.