2025-09-03 中国科学院（CAS）
＜関連情報＞
- https://english.cas.cn/newsroom/research_news/earth/202509/t20250903_1052706.shtml
- https://www.cell.com/one-earth/fulltext/S2590-3322(25)00254-4
地球システムモデルにおける全球植生生産性の最適温度に関する誤った表現 Misrepresented optimum temperatures for global vegetation productivity in Earth system models
Yiheng Wang ∙ Jianyang Xia ∙ Yuanyuan Huang ∙ Chenyu Bian ∙ Shuli Niu
One Earth Published:September 2, 2025
DOI:https://doi.org/10.1016/j.oneear.2025.101428
Graphical abstract
Science for society
Land ecosystems absorb carbon from the atmosphere, slowing down climate change. Scientists and policymakers depend on Earth system models (ESMs) to estimate how much carbon ecosystems can absorb in the future, which is vital for climate policy, carbon budgeting, and land management strategies. However, the rate of carbon uptake, known as gross primary productivity (GPP), is strongly influenced by temperature and can decline once it exceeds an optimum level (). In this study, we found that ESMs overestimate and fail to capture its increase over time, particularly in dry and cold ecosystems. These biases suggest that models may overestimate the positive effects of warming on land carbon uptake, highlighting the need to better capture the complex ecological processes that regulate GPP under high temperatures. Improving the model representation of and ecosystem-scale responses to rising temperatures is critical not only for reliable climate projections but also for sustaining ecosystem functions and services that benefit nature and human society and informing decision-making and international efforts to mitigate climate change.
Highlights
- ESMs overestimate optimum temperature () for GPP in 60.3% of land ecosystems
- ESMs underestimate the increase in under climate change
- reveals key model bias in vegetation structure and water limitations
- ESMs need better incorporation of temperature acclimation for GPP prediction
Summary
Accurately predicting the responses of gross primary productivity (GPP) to warming is essential for constraining the global carbon cycle and its feedback to climate change. GPP increases with temperature but declines beyond a threshold, known as the ecosystem optimum temperature (). A realistic representation of is therefore crucial for reliable projections of GPP and terrestrial carbon uptake. However, whether current Earth system models (ESMs) capture remains unclear. Here, we evaluated ESMs’ representation of and its temporal trends using ground observations and remote-sensing products from 1982 to 2013. We found that ESMs overestimated or failed to capture across 60.3% of ecosystems, especially in arid regions, due to misrepresented water limitations and vegetation structure changes under high temperatures. Furthermore, ESMs underestimated the observed temporal increase in , indicating their limited capacity to replicate ecosystem temperature acclimation. These findings reveal significant uncertainties in GPP projections and offer critical insights to improve carbon-climate feedback predictions.
