Blue Carbon When Environmentalists Deny Climate Change Edward

Blue Carbon: When Environmentalists Deny Climate Change Edward P. Richards, JD, MPH Director: LSU Law Center Climate Change Law and Policy Project Clarence W. Edwards Professor of Law John P. Laborde Endowed Professorship in Energy Law LSU Law School

What is Blue Carbon? • Carbon sequestered in coastal wetlands, including salt marsh and woody plants such as mangroves. • These plants, especially salt marsh, are highly productive ecosystems and under ideal conditions can sequester large amounts of carbon in their roots and the peat from partially degraded stems and leaves. • Much of the “soil” on the delta is organic matter from these wetland plants. • The Blue Carbon initiative is based on creating new coastal wetlands to restore the lost land paying for them by selling carbon offset credits.

Study Sees $1. 6 Billion For Blue Carbon In Louisiana Wetlands

Key Factors in Effective Carbon Sequestration • The total amount of carbon sequestered. • This is the usual figure reported in promoters of carbon sequestration projects. • The net amount of carbon sequestered. • This subtracts the carbon necessary to create and maintain the sequestration system. • The failure mode of the sequestration system • What is the probably through time that the project will fail and what happens to the carbon when the project does fail?

Carbon Sequestration in Manufactured Wetlands • Artificial wetlands can accumulate significant amounts of carbon through time. • Coastal wetland creation usually requires significant dredging to initially build the wetland. Dredging is very energy intensive, usually diesel fuel. For example, the Louisiana Master Plan has approximately $20 B in dredging costs. The majority of that cost is the diesel fuel to drive the dredges. • The carbon foot of the newly created wetland is very high, that it may be many years before the wetland sequesters enough carbon to offset the carbon released to create the wetland. This is usually ignored.

The Lifetime of Sequestered Carbon • The usual focus of carbon offset programs is the amount of carbon sequestered at the moment that an offset is purchased. • Buy an acre of rainforest and fly guilt free • The lifetime of the offset is as critical. • The offset does not need to last forever, but it needs to last far enough into the future to start releasing carbon into a stable, decarbonized world in which a gradual stream of new carbon can be absorbed by the ecosystem. • This would be, at minimum, 100 years for a system whose failure then bleeds the carbon into the system over decades.

Lessons from Mitigation Banks • The best data on the stability of created wetlands is from studies of wetlands created as mitigation for wetlands destroyed by construction projects. • These mitigation banks do not tend to persist through time, despite the permitting requirement that the mitigation bank owner maintain the bank for the indefinite future. • When they fail, much of the sequestered carbon is released. • There are no politically acceptable legal tools to assure long term maintenance of mitigation bank wetlands.

Coastal Wetlands and Sea Level Rise • Healthy coastal wetlands are stable in the face of low rates of relative sea level rise (RSLR), < 5 mm a year. • They can build elevation – sequestering more carbon – to keep up with the sea level rise. • At some point between 5 -10 mm a year of RSLR, they can not longer keep up and they drown. • This is a catastrophic failure. The wetlands go to open water and the carbon is lost back to the atmosphere very quickly. • Mangroves fail over a longer period – years – but they are also drown as RSLR increases.

The Future of Sea Level Rise • While the exact rate of acceleration in sea level rise is uncertain, it is clearly underway. • Global sea level rise is about 3. 4 mm/y • Local sea level rise alone is now more than 5 mm/y on the Gulf Coast and parts of the US Atlantic coast. In Louisiana, there is also a significant subsidence component, raising to RSLR to more 30 mm/y in places. • We are already seeing significant coastal wetland loss from RSLR along the Atlantic and Gulf Coasts.

RSLR and Blue Carbon • As restoration projects, constructed wetlands are built in the areas where wetlands have already been lost, or are well into failure from RSLR. • Dredge spoil – at huge carbon and monetary costs – is piled into these areas and they are seeded with wetland plants. • The increased elevation gives them a few years head start on sea level rise, but the spoil is destabilized and eroded by storms fairly quickly. • In Louisiana, the loading may increase subsidence rates, raising RSLR • As reference, restored barrier islands seldom last one season, with $50/100, 000 of dredging cost and tens of millions tons of carbon wasted.

Blue Carbon over 100 Years • Even the conservative estimates of sea level rise over the next 100 year will force the coast miles inland. • In previous glacial melt cycles, wetlands do not resist at the edges of coasts, but are drowned. They can migrate inland if the land is flat and the conditions are favorable. • When Blue Carbon projects fail, they lose all the sequestered carbon, plus the carbon of construction, which is already in the atmosphere. • Along the Gulf and Atlantic coasts, it is unlikely that these projects will persist at current levels of RSLR, much less an accelerating rate of sea level rise.

Conclusion • Blue Carbon projects will fail over relatively short timeframes. • Accounting for carbon of construction, they will increase net carbon in the atmosphere over not building them at all. • Current legal standards for carbon offsets and wetland constructions only focus on the very short-term and thus create an economic incentive to build these projects, despite their net negative carbon footprint.