Blue Carbon Investment Potential in Lamu and Kwale Counties of Kenya: Carbon Inventory and Market Prospects

Blue carbon ecosystems, particularly mangroves, seagrasses, and salt marshes, play a crucial role in climate regulation by capturing and storing huge stocks of carbon. Together with supporting fisheries production, protecting shorelines from erosion, and supplying timber and non-timber products to communities, blue carbon ecosystems offer investment opportunities through carbon markets, thus supporting climate change mitigation and sustainable livelihoods. The current study assessed above- and below-ground biomass, sediment carbon, and the capacity of the blue carbon ecosystems in Kwale and Lamu Counties, Kenya, to capture and store carbon. This was followed by mapping of hotspot areas of degradation and the identification of investment opportunities in blue carbon credits. Carbon densities in mangroves were estimated at 560.23 Mg C ha−1 in Lamu and 526.34 Mg C ha−1 in Kwale, with sediments accounting for more than 70% of the stored carbon. In seagrass ecosystems, carbon densities measured 171.65 Mg C ha−1 in Lamu and 220.29 Mg C ha−1 in Kwale, values that surpass the national average but are consistent with global figures. Mangrove cover is declining at 0.49% yr−1 in Kwale and 0.16% yr−1 in Lamu, while seagrass losses in Lamu are 0.67% yr−1, with a 0.34% yr−1 increase in Kwale. Under a business-as-usual scenario, mangrove loss over 30 years will result in emissions of 4.43 million tCO2e in Kwale and 18.96 million tCO2e in Lamu. Effective interventions could enhance carbon sequestration from 0.12 to 3.86 million tCO2e in Kwale and 0.62 to 19.52 million tCO2e in Lamu. At the same period, seagrass losses in Lamu would emit 5.21 million tCO2e. With a conservative carbon price of 20 USD per tCO2e, projected annual revenues from mangrove carbon credits amount to USD 3.59 million in both Lamu and Kwale, and USD 216,040 for seagrass carbon credits in Lamu. These findings highlight the substantial climate and financial benefits of investing in the restoration and protection of the two ecosystems.