Carbon

1. 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

2. 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 and paying for them by selling carbon offset
credits.

4. Study Sees $1.6 Billion For Blue Carbon In
Louisiana Wetlands

5. 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?

6. 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
$20B 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.

7. 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.

8. 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.

9. 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 5-10mm 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.

10. 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 3.4mm/y
• Local sea level rise alone is now more than 5mm/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 30mm/y in
places.
• We are already seeing significant coastal wetland loss from RSLR
along the Atlantic and Gulf Coasts.

11. 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
$50/100,000,000 of dredging cost and tens of millions tons of carbon
wasted.

12. 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.

13. 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.