368
erosion can be suppressed by blue carbon ecosystems in places where the degree
and frequency of wind-driven waves will increase in the future due to climate
change. Furthermore, current velocity also decreases due to the presence of vegetation, and suspended matter is trapped and settles in the blue carbon ecosystems.
This process raises the elevation of the ecosystems due to sediment deposition, such
that they can keep up with projected sea level rise due to climate change. Overall,
utilization of vegetated coastal ecosystems can be an effective climate change measure in terms of both mitigation and adaptation.
Moreover, coral reef ecosystems have great wave attenuation effects due to their
reef topography. Coral reefs formed in the tropics and subtropics have a width of
several hundred meters to several kilometers, and rising ridges are often formed off
the reef. This coral reef topography functions as a natural breakwater because the
waves from the open ocean break around the reef ridge, and large waves generated
by storms are prevented from reaching the coast. Furthermore, because corals and
foraminifera grow up to near the low water level and form land foundations by calcification, coral reef ecosystems can be utilized as an autonomous adaptation measure to sea level rise due to climate change.
13.7 Concluding Remarks
We compiled the carbon flows and stocks related to climate change mitigation,
based on data reported in previous chapters and the literature. Although the functioning of both blue carbon storage and CO 2 gas exchange should be focused on
when SCEs are utilized to mitigate climate change, an information gap regarding
these two key processes has hindered our integrated understanding of blue carbon
science. Thus, in this book we aimed to quantitatively explain the mechanisms and
extent of the key processes, using a global review of the literature and many Japanese
case studies.
We also extended the definition of classical blue carbon ecosystems (mangroves,
seagrass meadows, and tidal marshes) to include macroalgal beds, tidal flats, coral
reefs, and urbanized shallow waters to show the potential of these additional ecosystems to serve as carbon sinks. Such an extension allowed us to focus on carbon
storage in sediments as well as that in the water column as refractory organic carbon
and at offshore sites such as the deep sea.
We also discussed the scientific and technological knowledge regarding blue carbon as it relates to the international governance of societies and communities as
well as possible future developments. We described the international policies and
frameworks related to blue carbon and introduced a case study of the application
and implementation of carbon offset credit in Japan. We anticipate that it will be
important to explore ways to introduce new funds and market economy mechanisms
to assist in policy planning, community design, and the conservation, restoration,
and management of SCEs.
T. Kuwae and M. Hori
erosion can be suppressed by blue carbon ecosystems in places where the degree
and frequency of wind-driven waves will increase in the future due to climate
change. Furthermore, current velocity also decreases due to the presence of vegetation, and suspended matter is trapped and settles in the blue carbon ecosystems.
This process raises the elevation of the ecosystems due to sediment deposition, such
that they can keep up with projected sea level rise due to climate change. Overall,
utilization of vegetated coastal ecosystems can be an effective climate change measure in terms of both mitigation and adaptation.
Moreover, coral reef ecosystems have great wave attenuation effects due to their
reef topography. Coral reefs formed in the tropics and subtropics have a width of
several hundred meters to several kilometers, and rising ridges are often formed off
the reef. This coral reef topography functions as a natural breakwater because the
waves from the open ocean break around the reef ridge, and large waves generated
by storms are prevented from reaching the coast. Furthermore, because corals and
foraminifera grow up to near the low water level and form land foundations by calcification, coral reef ecosystems can be utilized as an autonomous adaptation measure to sea level rise due to climate change.
13.7 Concluding Remarks
We compiled the carbon flows and stocks related to climate change mitigation,
based on data reported in previous chapters and the literature. Although the functioning of both blue carbon storage and CO 2 gas exchange should be focused on
when SCEs are utilized to mitigate climate change, an information gap regarding
these two key processes has hindered our integrated understanding of blue carbon
science. Thus, in this book we aimed to quantitatively explain the mechanisms and
extent of the key processes, using a global review of the literature and many Japanese
case studies.
We also extended the definition of classical blue carbon ecosystems (mangroves,
seagrass meadows, and tidal marshes) to include macroalgal beds, tidal flats, coral
reefs, and urbanized shallow waters to show the potential of these additional ecosystems to serve as carbon sinks. Such an extension allowed us to focus on carbon
storage in sediments as well as that in the water column as refractory organic carbon
and at offshore sites such as the deep sea.
We also discussed the scientific and technological knowledge regarding blue carbon as it relates to the international governance of societies and communities as
well as possible future developments. We described the international policies and
frameworks related to blue carbon and introduced a case study of the application
and implementation of carbon offset credit in Japan. We anticipate that it will be
important to explore ways to introduce new funds and market economy mechanisms
to assist in policy planning, community design, and the conservation, restoration,
and management of SCEs.
T. Kuwae and M. Hori