Global teal carbon: Stocks, sequestration, and its potential role in climate change mitigation

Abstract

A colour-based nomenclature has developed in recent decades to characterise the distribution and distinct functions of organic carbon in natural ecosystems. ‘Teal carbon’, which is found in shallow inland freshwater wetlands, is the newest type of carbon added to the colour spectrum. Teal carbon ecosystems are more susceptible to anthropogenic activities and climate change than green and blue carbon ecosystems. A detailed global review of major teal carbon ecosystems was performed to highlight the status of teal carbon and its potential role in mitigating global climate change. Our estimates indicate that peatlands, (non-tidal freshwater) swamps, and (non-tidal freshwater) marshes store (mean ± standard deviation) approximately 101.63 ± 68.12 (1016 ± 681), 42.82 ± 40.01 (428 ± 400), and 13.97 ± 10.77 (140 ± 108) kg C m⁻² (Mg C ha⁻¹), respectively. The study highlights teal carbon ecosystems as major natural carbon emitters, with methane emissions of 68.79 ± 237.58, 30.48 ± 53.17, and 104.37 ± 130.82 g C-CH₄ m⁻² yr⁻¹, and carbon dioxide emissions of 644.59 ± 1018.56 and 713.07 ± 881.75 g C-CO₂ m⁻² yr⁻¹, respectively. On the other hand, peatlands, swamps, and marshes store considerable atmospheric carbon at the rate (mean ± standard deviation) of 125.5 ± 16.5, 216.7 ± 255.8 and 180 ± 170.5, respectively. Due to its extensive global reach and high annual carbon sequestration rate, teal carbon ecosystems have the highest global carbon sequestration potential, surpassing blue and green carbon ecosystems if they are properly conserved and managed. Therefore, the Development of Self-sustaining Teal Carbon Zones (DSTCZ) can be a natural climate solution (NCS) providing numerous ecosystem services to society. Conservation, restoration, and improved global datasets are necessary to enhance the natural carbon storage efficacy of ecosystems and refine climate projections.