Satellite-Based Study Shows That U.S. Tidal Wetlands Increased Carbon Sequestration by Vegetation Via Photosynthesis by 6% in 20 Years, in Addition to Other Ecosystem Benefits

     Gross primary production (GPP) is a metric that quantifies how much carbon is fixed by vegetation via photosynthesis and is important for understanding potential carbon sequestration. Tidal wetlands provide several ecosystem benefits, including storing carbon, protecting shorelines, and supporting biodiversity. The vegetation basically “fixes” carbon by storing it in the ground for the plants to access rather than losing it to the atmosphere.

     A new study published in Global Biogeochemical Cycles looked at satellite data from 2001 to 2020 and determined that GPP and carbon sequestration increased by 6% over that time period. The study looked at seven coastal regions in the U.S. The researchers found that the strongest increases occurred in the Gulf and southern Atlantic regions.

     According to Eos:

“The increases are driven by climate changes—namely, warming trends and increased sunlight. In contrast, changes in the enhanced vegetation index (EVI), used to quantify greenness, contributed to a slight decrease in overall GPP.”

     Hurricanes, tropical storms, flooding, and drought all cause variability in the GPP, but temperature is the strongest driver of variability, followed by shortwave radiation and then EVI.

“Overall, these findings suggest that shifts in temperature and sunlight—rather than changes in vegetation—are responsible for increases in tidal wetland productivity and that this information should be considered when managing tidal wetlands or creating carbon cycle models.”

     

     More of the paper's highlights are given below:

     According to the paper, the results suggest that they should be incorporated into climate models and suggest where future studies should be directed:

“These findings highlight the increasing influence of climate forcing on tidal wetland productivity and show that recent productivity gains are driven primarily by climatic factors rather than changes in vegetative canopy and its greenness. This underscores the importance of incorporating climate-related drivers into tidal wetland carbon models and management strategies. While climate-driven increases in GPP may enhance carbon sequestration potential, localized vegetation stressors—such as salinity intrusion and disturbance events—remain critical constraints.”

“Future research should integrate hydrological and biogeochemical feedbacks to improve predictions of tidal wetland resilience under accelerating climate change. In particular, exploring interactions with the Palmer Drought Severity Index and potential implications for salinity stress is a valuable avenue for future work. Additionally, in this study, we did not evaluate changes in tidal wetland extent over the analysis period; therefore, incorporating dynamic wetland extent would be an important and valuable improvement over the static extent used here and a useful direction for future work. Another valuable direction would be validation of the GPP model against flux tower data collected since 2017, after the end of the GPP model training period (2004–2017).”   

 

References:

 

Satellite record reveals US tidal wetland productivity rose 6% in 20 years. Rebecca Owen. Phys.org. Eos. July 7, 2026. Satellite record reveals US tidal wetland productivity rose 6% in 20 years

Climate-Driven Long-Term Increase in Tidal Wetland Gross Primary Production in the United States. Maria Herrmann, Raymond G. Najjar, Rusty A. Feagin, Jose D. Fuentes, Thomas P. Huff, Wenzhe Jiao, and Joshua E. Lerner. Global Biogeochemical Cycles. Volume 40, Issue 5. May 2026. Climate‐Driven Long‐Term Increase in Tidal Wetland Gross Primary Production in the United States - Herrmann - 2026 - Global Biogeochemical Cycles - Wiley Online Library