Blue Carbon Financing of Mangrove Conservation in the Abidjan Convention Region: A Feasibility Study

Table 9: Blue carbon stocks in West, Central and Southern Africa: area of habitats and carbon stored

Area (ha)

Carbon stored in biomass and topmeter of soil (Tg)

Salt marshes

Salt marshes

Total

Total

Seagrasses

Seagrasses

Mangroves

Country

Mangroves

49 3 15 4 13 1 11 27 2 14 18 40 14 29 23 5

190,900 11,100 56,400 15,500 50,100 5,400 43,400 103,200 8,800 53,200 68,700 152,700 53,000 112,800

64 23 80 5 14 7 19 93 25 55

266,350 148,708 204,700 17,000 53,300 23,700 61,500 248,900 60,711 332,658

8 19 – – – – – – – 38

60,050 135,808 – – – – – – – 271,858

7 1 65

Angola Benin Cameroon Congo Côte d’Ivoire D.R. Congo Eq. Guinea Gabon Gambia

15,400 1,800 148,300

1 1 6 8

1,500 3,200

18,300 18,100 145,700 51,911 7,600

66 22 3 82 116 8 0 377 ND 50 41 0 854

Ghana Guinea Guinea-Bissau Liberia Mauritania Nigeria SãoTomé and Príncipe Senegal Sierra Leone

281 373

1,558,692 1,994,211 71,900 112,840 1,830,595 20,600 327,582 620,348 24,204 7,978,498

181 217 – – 123 – 21 62 3 673

1,301,092 1,560,911

188,900 280,600 18,900 40 857,300 ND 120,000 95,500 200 1,973,251

22 29 523 5 85 123 4 1,830

– – 884,495 –

88,800 20,600 55,600 77,600 5,200 1,173,000

14 20 1 303

151,982 447,248 18,804 4,832,247

Togo Total

Note: Blue carbon areas were estimated for each country (GADM 2015) using ESRI ArcMap 10.3 Spatial Analyst Intersect Tool for vector data and Zonal Statistics as Table Tool for raster data. Carbon stored was calculated as the sum of (1) mean above-ground biomass (Hutchison et al., 2014), (2) mean below-ground biomass (Hutchison et al., 2014), and (3) mean soil carbon (Jardine and Siikamäki, 2014), multiplied by coverage of each blue carbon resource. Formangroves, mean carbon content in biomass in (1) and (2) were calculated using biomass-to-carbon ratios of 1:0.46 and 1:0.39, respectively, after Howard, Hoyt et al. (2014), page 78 and 90, respectively. For seagrasses, a carbon per hectare value of 139.2 tC/ha was used based on Pendleton, Murray et al. (2014). For salt marshes, a carbon per hectare value of 258.7 tC/ha was used based on Pendleton, Murray et al. (2014). Sources: Green and Short (2003); Halpern,Walbridge et al. (2008); Fatoyinbo and Simard (2013); Pendleton, Murray et al. (2014).

to address this challenge will be the results from a NASA- funded project (2014 to 2018) that will estimate blue carbon stocks, which may provide the most accurate data to date.*

biomass carbon above and below ground, as well as soil carbon. For mangroves, this data is used in Table 9 to estimate carbon stored in biomass the topmeter of soil. For seagrasses and salt marshes, an average carbon storage value is used from the literature. Trends in the size and distribution of blue carbon stocks inWest, Central and Southern Africa The data sets summarized in Table 9 do not lend themselves to time-series analyses of trends, given that

Table 8 provides detail on the extent and nature of blue carbon stocks in mangrove forests, based on storage of

*Total Carbon Estimation in African Mangroves and Coastal Wetlands in Preparation for REDD and Blue Carbon Credits. Available at http://cce.nasa.gov/cgi-bin/cce/cce_ profile.pl?project_group_id=3132. Last accessed 27 September 2015.

25