正および負のCO2排出下における炭素循環フィードバックと過渡気候応答の非対称性
Asymmetry in carbon cycle feedbacks and transient climate response under positive and negative CO 2 emissions (原題)
V. Rachel Chimuka, Kirsten Zickfeld
🤖 gxceed AI 要約
日本語
地球システムモデルを用いて、正と負のCO2排出に対する炭素循環フィードバックと気候応答の非対称性を調べた。負の排出では、濃度-炭素フィードバックは大きいが、気候-炭素フィードバックは小さい。また、負の排出による気温変化は正の排出よりも大きい。この結果は、負の排出シナリオに基づく気候目標の評価に重要である。
English
Using an Earth system model, this study investigates asymmetries in carbon cycle feedbacks and climate response under positive vs. negative CO2 emissions. It finds that concentration-carbon feedback is larger while climate-carbon feedback is smaller under negative emissions, and that negative emissions cause greater temperature change per unit CO2 than positive emissions. This highlights the need for metrics specific to negative emissions for accurate climate target assessment.
Unofficial AI-generated summary based on the public title and abstract. Not an official translation.
📝 gxceed 編集解説 — Why this matters
日本のGX文脈において
日本は2050年カーボンニュートラルを掲げ、ネガティブエミッション技術（DACCSやBECCS）の導入を検討している。本研究成果は、これらの技術の効果を過大評価しないための科学的根拠を提供し、日本の気候政策や企業の長期戦略に示唆を与える。
In the global GX context
Globally, many net-zero pathways rely on carbon dioxide removal. This paper provides crucial evidence that metrics derived from positive emissions may misestimate the climate response to negative emissions, informing the design of carbon removal policies and the accounting of their effectiveness under the Paris Agreement.
👥 読者別の含意
🔬研究者:Provides quantitative evidence of asymmetry in carbon cycle feedbacks, essential for improving Earth system models and carbon budget estimates.
🏛政策担当者:Informs the calibration of carbon removal targets and the development of metrics for negative emissions in climate policy frameworks.
📄 Abstract（原文）
Abstract. Most emissions scenarios consistent with limiting warming to well below 2 °C above pre-industrial levels rely on carbon dioxide removal to offset residual positive emissions or achieve net-negative emissions. While carbon cycle and climate metrics are well quantified for positive CO2 emissions, applying the same metrics under negative emissions may over- or underestimate the effectiveness of carbon dioxide removal. This study uses an Earth system model to investigate the asymmetry in carbon cycle feedbacks and climate response under positive and negative CO2 emissions. To this end, symmetric concentration-driven simulations are initialized from a state at equilibrium with twice the preindustrial CO2 concentration and run in biogeochemically coupled, radiatively coupled and fully coupled modes. Our results suggest that land and ocean carbon cycle feedbacks are asymmetric. Compared to their respective magnitudes under positive emissions, the concentration-carbon feedback is larger, whereas, the climate-carbon feedback is smaller under negative emissions. Asymmetries in land carbon cycle feedbacks arise from the saturation of the CO2 fertilization effect and asymmetric temperature and soil respiration responses. Asymmetries in ocean carbon cycle feedbacks are driven by non-linear responses to CO2 and temperature change, as well as asymmetric ocean circulation responses. Asymmetries in carbon cycle feedbacks propagate onto asymmetry in the Transient Climate Response to Cumulative CO2 Emissions: a negative CO2 emission results in greater global mean temperature change than a CO2 emission of the same magnitude. Our study highlights the need to quantify metrics under negative emissions as reliance on metrics derived from positive emission scenarios may result in inaccurate quantification of the climate response under net negative CO2 emissions.
🔗 Provenance — このレコードを発見したソース
- openalex https://doi.org/10.5194/bg-23-6211-2026first seen 2026-09-09 05:02:01
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