ABSTRACT
Coastal blue carbon ecosystems occur mainly in estuaries and deltas, which is where 20% of the human population of the planet live at densities that are three-fold that in inland areas. While the effects of human impacts are evident on all coastal wetland types, this chapter focuses on mangrove, seagrass, and tidal marshes. Tidal marshes are the dominant blue carbon ecosystem over much of the temperate zone and polar coastal regions of the world but also occur in the high intertidal zone in the tropics. Blue carbon habitats are affected by human impacts such as land conversion, interactions between human activities and climate change factors. Large-scale human impacts on mangrove forests have been relatively, though mangroves were overexploited historically such as the use of mangrove timber to construct fleets of boats and for the construction of buildings on the east coast of Africa.
