Shin et al. (2026) Negative CO2 emissions for long-term mitigation of extremes in land hydrological cycle

Identification

• Journal: Nature Communications
• Year: 2026
• Date: 2026-03-23
• Authors: Jongsoo Shin, Jong‐Seong Kug, So‐Won Park, Jonghun Kam, Soon-Il An, So-Eun Park, Hyoeun Oh, Sang-Wook Yeh, Sujong Jeong, Chang-Kyun Park, Jin-Soo Kim
• DOI: 10.1038/s41467-026-70945-8

Research Groups

• Physical Oceanography Department, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
• School of Earth and Environmental Sciences, Seoul National University, Seoul, Republic of Korea
• Division of Environmental Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea
• Department of Atmospheric Sciences, Yonsei University, Seodaemun-gu, Seoul, Republic of Korea
• Center for Climate Physics, Institute for Basic Science, Busan, Republic of Korea
• Pusan National University, Busan, Republic of Korea
• Department of Marine Science and Convergent Engineering, Hanyang University, Ansan, Republic of Korea
• Department of Environmental Planning, Graduate School of Environmental Studies, Seoul National University, Seoul, Republic of Korea
• Climate Technology Center, Seoul National University, Seoul, Republic of Korea
• Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea

Short Summary

This study investigates terrestrial precipitation and vegetation feedbacks under idealized zero and negative CO2 emissions scenarios, finding that sustained negative emissions are crucial for long-term mitigation of hydrological extremes and enhanced water availability, primarily due to amplified transpiration.

Objective

• To investigate the responses of terrestrial precipitation and vegetation feedbacks under idealized zero and negative CO2 emissions scenarios, and to quantify their impacts on the terrestrial hydrological cycle and associated extreme events.

Study Configuration

• Spatial Scale: Global (60°S to 90°N, excluding Antarctica), with regional analyses based on IPCC AR6 WGI domains. Model resolutions: atmosphere ~1°, ocean ~1° (meridional ~0.27° near the equator).
• Temporal Scale: Long-term integration experiments (2000-2400, 400 years). Analysis periods include a reference period (2001-2030), peak CO2 concentration (MAX, 2091-2120), and a restoring period (RS, 2300-2399).

Methodology and Data

• Models used: Community Earth System Model version 2 (CESM2), which includes:
  • Community Atmosphere Model version 6 (CAM6)
  • Parallel Ocean Program version 2 (POP2)
  • Community Ice CodE version 5 (CICE5)
  • Community Land Model Version 5 (CLM5)
  • Marine Biogeochemistry Library (MARBL)
• Data sources:
  • Idealized CO2 emission-driven simulations for Zero Emissions (ZE) and Negative Emissions (NE) scenarios.
  • Nine ensemble members for each scenario.
  • An additional idealized experiment (NE-LAND) to isolate physiological feedback effects.
  • Initial emission increase rate based on the Shared Socioeconomic Pathway 5-8.5 (SSP5-8.5) scenario.
  • Expert Team on Climate Change Detection and Indices (ETCCDI) for extreme precipitation (Rx1day) and wet days, and soil moisture content for drought index.

Main Results

• Terrestrial precipitation increases by approximately 1.1% at peak CO2 concentration (~725 ppm), but shows even greater increases of about 1.9% under zero emissions (~600 ppm) and 2.5% under negative emissions (~430 ppm).
• Under the negative emissions scenario, enhanced transpiration from terrestrial vegetation largely contributes to this increase, leading to a notable "overshoot" in land precipitation despite lower temperatures compared to the zero emissions scenario.
• Despite a substantial increase in terrestrial precipitation, extreme precipitation events and droughts become less severe globally under the negative emissions scenario, even compared to the zero emissions scenario.
• An additional experiment (NE-LAND) demonstrated that the reduction in transpiration due to a high CO2 environment significantly contributes to decreased land precipitation, underscoring the critical role of physiological feedback.
• Negative emissions lead to the alleviation of either heavy precipitation or drought in most regions, with increased precipitation frequency distributing rainfall more evenly and enhancing water resource efficiency.

Contributions

• Advances understanding of precipitation responses to CO2 removal by employing an emissions-driven experiment with a fully interactive carbon cycle, which captures CO2 outgassing and provides a more realistic representation of physiological feedbacks.
• Reveals the critical role of physiological processes, particularly the recovery and amplification of transpiration, in driving precipitation changes under negative emissions, distinguishing these responses from those under positive emissions.
• Highlights that sustained negative emissions are crucial for achieving long-term reductions in hydrological extremes and enhancing terrestrial water availability, especially in densely populated regions, beyond what zero emissions can achieve.
• Emphasizes the importance of vegetation in shaping hydrological outcomes under extended mitigation scenarios and the value of emissions-based experiments for capturing long-term Earth system feedbacks.

Funding

• National Research Foundation of Korea (NRF) grant (NRF-2022R1A3B1077622)
• Korea Environment Industry & Technology Institute (KEITI) Project (RS-2023-00232066)
• Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (RS-2024-00413360)
• Woods Hole Oceanographic Institution (WHOI) Grow The Base Fund
• National Center for Meteorological Supercomputer of Korea Meteorological Administration (KMA)
• National Supercomputing center (KSC-2025-CHA-0001)
• Korea Research Environment Open NETwork (KREONET)

Citation

@article{Shin2026Negative,
  author = {Shin, Jongsoo and Kug, Jong‐Seong and Park, So‐Won and Kam, Jonghun and An, Soon-Il and Park, So-Eun and Oh, Hyoeun and Yeh, Sang-Wook and Jeong, Sujong and Park, Chang-Kyun and Kim, Jin-Soo},
  title = {Negative CO2 emissions for long-term mitigation of extremes in land hydrological cycle},
  journal = {Nature Communications},
  year = {2026},
  doi = {10.1038/s41467-026-70945-8},
  url = {https://doi.org/10.1038/s41467-026-70945-8}
}