Table 1. Estimates of carbon released by land-use change in coastal ecosystems globally and associated economic impact.

	Inputs			Results
Ecosystem	Global extent (Mha)	Current conversion rate (% yr−1)	Near-surface carbon susceptible (top meter sediment+biomass, Mg CO2 ha−1)	Carbon emissions (Pg CO2 yr−1)	Economic cost (Billion US$ yr−1)
Tidal Marsh	2.2–40 (5.1)	1.0–2.0 (1.5)	237–949 (593)	0.02–0.24 (0.06)	0.64–9.7 (2.6)
Mangroves	13.8–15.2 (14.5)	0.7–3.0 (1.9)	373–1492 (933)	0.09–0.45 (0.24)	3.6–18.5 (9.8)
Seagrass	17.7–60 (30)	0.4–2.6 (1.5)	131–522 (326)	0.05–0.33 (0.15)	1.9–13.7 (6.1)
Total	33.7–115.2 (48.9)			0.15–1.02 (0.45)	6.1–41.9 (18.5)

Notes: 1 Pg = 1 billion metric tons. To obtain values per km², multiply by 100. See Methods section for detailed description of inputs and their sources. In brief, data for global extent and conversion rate are recently published ranges (minimum - maximum, and central estimate in parentheses). For near-surface carbon susceptible to land-use conversion (expressed in potential CO₂ emissions [48]–[50]), uncertainty range is based on assumption of 25–100% loss C upon land-use impact; thus, the high-end estimate is the literature-derived global mean carbon storage in vegetation and the top meter of sediment only (central estimate is thus 63% loss). Results for carbon loss are non-parametric 90% confidence intervals (median in parentheses) from Monte Carlo uncertainty propagation of the three input variables (see Methods). Economic estimates apply a multiplier of US$ 41 per ton of CO₂ to lower, upper, and central emission estimates (see Methods).