This report focuses on the management of natural coastal carbon sinks. The produc�on of the report has been s�mulated by an apparent lack of recogni�on • and focus on coastal marine ecosystems to comple- ment ac�vi�es already well advanced on land to ad- dress the best prac�ce management of carbon sinks.
The produc�on of this report is �mely as a number of Governments are now introducing legisla�on to tackle climate change. In the UK, for example, the Climate Change Act sets out a statutory responsibility to quan-
�fy natural carbon sink as part of the overall carbon • accoun�ng process. It is important that such quan��- ca�ons and processes work with the latest science and evidence.
To construct this report we asked leading scien�sts
for their views on the carbon management poten�al
of a number of coastal ecosystems: �dal saltmarshes, mangroves, seagrass meadows, kelp forests and coral • reefs. The resultant chapters wri�en by these scien�sts form the core of this report and are their views on how well such habitats perform a carbon management role. These ecosystems were selected because the belief from the outset was that they are good at sequestering carbon, and are located in situa�ons where manage- ment ac�ons could secure the carbon sinks. There are
of course other features of our ocean that are already • established as good carbon sinks – the key focus for this ini�al work has, however, been on those ecosystems where management interven�on can reasonably read-
ily play a role in securing and improving the future state
of the given carbon sinks. If proven this work could ex- pand the range of global op�ons for carbon manage- ment into coastal marine environments, unlocking many possibili�es for ac�on and possible �nancing of new management measures to protect the important • carbon sinks.
The key �ndings of this report are:
These key marine ecosystems are of high im- portance because of the signi�cant goods and services they already provide as well as the carbon management poten�al recog- nised in this report, thus providing new con- vergent opportuni�es to achieve many po- li�cal goals from few management ac�ons.
The carbon management poten�al of these se- lected marine ecosystems compares favourably with and, in some respects, may exceed the po- ten�al of carbon sinks on land. Coral reefs, rather than ac�ng as ‘carbon sinks’ are found to be slight ‘carbon sources’ due to their e�ect on local ocean chemistry
The table below highlights some of the key car- bon sink data documented in this report for these coastal habitats. It provides summary data on the comparison of carbon stocks and long-term accu- mula�on of carbon in the coastal marine ecosys- tems. Comparisons with informa�on on terrestrial carbon sinks are provided in the body of this report.
The chemistry of some speci�c marine sediments (for example salt marshes) suggests that whilst such habitats may be of limited geographical ex- tent, the absolute compara�ve value of the car- bon sequestered per unit area may well outweigh the importance of similar processes on land due to lower poten�al for the emission of other powerful greenhouse gases such as methane.
Alongside the carbon management poten�al of these ecosystems, another key �nding of this report is the lack of cri�cal data for some habitat types. Having comprehensive habitat inventories is cri�cally important and this report highlights the urgent need, alongside recognising the carbon role of such ecosystems, to ensure that such inventories are completed for saltmarsh and kelp forests and then all such inventories are e�ec�vely maintained over �me.
• These coastal marine ecosystems are also vital for the food security of coastal communi�es in developing countries, providing nurseries and �shing grounds for ar�sanal �sheries. Furthermore, they provide natural coastal defences that mi�gate erosion and storm ac�on. Therefore, be�er protec�on of these ecosystems will not only make carbon sense, but the co-bene�ts from ecosystem goods and services are clear.
• Signi�cant losses are occurring in the global extent of these cri�cal marine ecosystems due to poor management, climate change (especially rising sea levels), coupled to a lack of policy priority to address current and future threats.
• Certain human impacts – notably nutrient and sediment run-o� from land, displacement of mangrove forests by urban development and aquaculture, and over-�shing - are degrading these ecosystems, threatening their sustainability and compromising their capacity to naturally sequester carbon. The good news is that such impacts can be mi�gated by e�ec�ve management regimes.
• Management approaches already exist that could secure the carbon storage poten�al of these ecosystems, and most governments have commitments to put such measures in place for other reasons. These include biodiversity protec�on or achieving sustainable development. Agreed management approaches that would be e�ec�ve include Marine Protected Areas, Marine Spa�al Planning, area-based �sheries management approaches, bu�er zones to allow inland migra�on of
coastal carbon sinks, regulated coastal development, and ecosystem rehabilita�on.
• Greenhouse gas emissions that occur as a result of the management of coastal and marine habitats are not being accounted for in interna�onal climate change mechanisms (ie UNFCCC, Kyoto, CDM, etc) or in Na�onal Inventory Submissions.
Not only does this mean that countries are under- es�ma�ng their anthropogenic emissions, but also that the carbon savings from measures to protect and restore coastal and marine habitats will not count towards mee�ng interna�onal and na�onal climate change commitments.
This report provides the essen�al evidence needed to mo�vate discussions and ini�a�ves on how such coastal ecosystems should be incorporated into interna�onal and na�onal emission reduc�on strategies, na�onal greenhouse gas inventories and, poten�ally, carbon revenues schemes. The la�er could take the marine equivalent of the Reducing Emissions from Deforesta�on and Forest Degrada�on (REDD) scheme on land to safeguard these cri�cal coastal carbon sinks. Don’t just think REDD, think coastal too!
The evidence presented here makes clear why moving forward with Marine Protected Areas, Marine Spa�al Planning and area-based �sheries management techniques is not only a poli�cal impera�ve for biodiversity conserva�on, food security, and shoreline protec�on, but also now for helping mi�gate climate change.