@Article{Parazoo_Earth-SciRev_20260701,
 author		= {N. Parazoo and D. Carroll and J. B. Abshire and Y. M. Bar-On and R. A. Birdsey and A. A. Bloom and K. W. Bowman and R. K. Braghiere and L. M. Bruhwiler and B. Byrne and A. Chatterjee and D. Crisp and L. Duncanson and A. F. Feldman and A. M. Fox and C. Frankenberg and B. A. Gay and F. Hopkins and Forrest M. Hoffman and J. R. Holmquist and L. R. Hutyra and M. Keller and C. D. Koven and J. L. Laughner and J. Liu and N. S. Lovenduski and N. Macbean and G. A. McKinley and G. McNicol and D. Menemenlis and A. M. Michalak and C. E. Miller and H. Nesser and T. Oda and E. M. Ordway and L. E. Ott and K. Paustian and Z. A. Pierrat and B. Poulter and S. C. Reed and D. S. Schimel and S. P. Serbin and S. S. Saatchi and H. Suto and L. Windham-Myers and D. Wunch},
 title		= {A {U.S.} Scientific Community Review of Carbon Cycle Science Gaps and Opportunities to Better Support {E}arth System Science and Carbon Management},
 journal	= Earth-SciRev,
 volume		= {278},
 pages		= 105493,
 doi		= {10.1016/j.earscirev.2026.105493},
 day		= 1,
 month		= jul,
 year		= 2026,
 abstract	= {Greenhouse gas (GHG) emissions continue to grow, while natural carbon reservoirs are becoming increasingly vulnerable to anthropogenic pressures, climate extremes, and disturbance. These changes are impacting humans, ecosystems, and natural resources worldwide. Tracking and mitigating GHG emissions require a pivot to operational monitoring of regional carbon flux and stock changes. The current GHG observing system is addressing needs at two distinct scales: 1) Local scale ($<$1~km), related to anthropogenic point source emissions, and 2) global scales ($>$1000~km), related to land and ocean carbon sinks. More focus on intermediate (10--1000~km) scales is needed to more effectively monitor progress in reducing carbon emissions, enhancing removals, and maintaining sinks.Representatives from carbon cycle biomass and flux communities across United States government agencies and academic institutions met in September 2024 to discuss the rationale and scientific context for more effectively implementing an operational system for GHG monitoring in support of urban and national carbon management needs. To guide development of this system, we propose a multi-tiered global spaceborne observing framework for carbon flux and stock, prioritizing: 1) frequent GHG partial columns for carbon emissions and removals; 2) continuous time series and data fusion of biomass from Lidar and Synthetic Aperture Radar (SAR) for carbon stocks, and 3) expanded coverage of tropical, high latitude, and oceanic regions to monitor carbon cycle tipping points and feedbacks. This system should be complemented by expanded surface and airborne networks for oceanic and terrestrial/aquatic ecosystems for calibration, ground truthing, and study of under-sampled regions.

Plain language summary

The rate of growth in global CO$_2$ emissions has been in decline over the last decade following efforts to enact climate policy, shift to clean energy, and mitigate leaks from oil and gas facilities. This is good progress, but with emissions of both CO$_2$ and methane (CH$_4$) on the rise, time is running out to meet temperature targets. Spaceborne greenhouse gas (GHG) observations can help monitor emissions/removals and track progress at the urban- to country-level, but currently lack the frequency, coverage, and precision to do so. Representatives from the carbon cycle community convened in September 2024 to discuss viable options for addressing these limitations. We recommend a unified GHG observing system leveraging frequent (daily) sampling and vertical profiles of atmospheric GHGs to more accurately track carbon gains and losses, and harmonized maps of biomass to track growth, recovery, and disturbance. Expanded coverage of climate sensitive tropical, polar, and ocean regions is needed to monitor unexpected changes in the natural carbon cycle. Complementary data from airplanes and surface networks is needed to fill observational and science gaps. This system should prioritize timely delivery of carbon flux and stock information to support carbon management efforts.}
}