Tampa Bay Sea Level Rise & Coastal Habitat Migration Evaluation: Potential for "Blue Carbon" Benefits
Background
The TBEP has established restoration goals for important coastal habitats including: seagrass, mangroves, salt marshes, salt barrens and freshwater wetlands. Collectively, these habitats not only provide essential estuarine habitat to many of the fish and wildlife species that inhabit the Tampa Bay watershed, but they also provide vital ecosystem services to Tampa Bay's human population living within the watershed (e.g., storm surge/flood protection, recreational/tourism economic benefits, nutrient and carbon sequestration, etc.).
During the rapid coastal development period that occurred between the 1950s and 1980s, significant losses of these habitats were documented. Since the 1980s, the TBEP and its partners have worked collaboratively to restore these habitats with varying success. As mentioned above, seagrass extent in the Bay is now exceeding historic levels. Similarly, mangrove habitat extent is approaching historic 1950s levels and is expected to exceed historic levels as our regional climate becomes warmer in the future. However, salt marsh, salt barren and freshwater wetland habitat extents remain well below historic levels, despite significant efforts to restore many of these habitats in the watershed [see where restoration has occurred]. As such, the TBEP and its partners are looking for new incentives and policies to further protect, restore and recover these critical coastal habitats within the watershed.
"Blue Carbon" financed restoration is one potential option. "Blue Carbon" refers to the ecosystem services provided by these coastal habitats to capture and store green house gases from the atmosphere into plant tissues and wetland soils, thereby "sequestering" these gases from further contributions to global climate change. Because the Tampa Bay estuary is home to three primary blue carbon ecosystems (seagrass, mangrove and salt marsh habitats), opportunities to encourage continued public and private investment in new restoration and conservation measures utilizing blue carbon financing mechanisms is currently being investigated. Research from 2014-2016 was focused on the blue carbon benefits of Tampa Bay habitats and aimed to:
- determine the green house gas (GHG) sequestration benefits of existing coastal habitats and the climate change mitigation benefits derived from coastal habitat restoration efforts to date;
- determine the anticipated changes in GHG emission and removal from coastal habitats in response to anticipated future land development, sea level rise and climate change impacts; and,
- identify future land management options that sustain and expand upon current coastal habitat extent and carbon sequestration potential.
Outcomes from this research are helping to guide future coastal restoration and habitat management objectives in Tampa Bay and will contribute to both local and global efforts to restore coastal ecosystems for the added incentive of mitigating future GHG impacts.
View the Full Report and Summary of Findings
An addendum to the reported "Blue Carbon" benefits of these habitats elaborates on the technical details that went into the GHG analysis.
Visualize Changes to Tampa Bay Habitats and the Resulting "Blue Carbon" Benefits in the Future
While the future has unknowns, models based on the best available information have been used to estimate how Tampa Bay's habitats may change depending on future sea level rise rates, the habitats' response to higher sea level rise rates (varying rates of soil accretion), and potential policy decisions on whether vulnerable coastal land uses should be protected. To glimpse at how Tampa Bay's critical coastal habitats may look in the future and how these changes may impact GHG emissions long term, please explore the above tabs. The series of tabs listed above provide a visual summary of the model predictions developed under this project and as described in the reports referenced above. Each browser tab represents a specific model "run" or scenario for future coastal conditions in Tampa Bay. Six model runs were developed as follows:
| Run | Habitat Accretion Rates | Sea Level Rise Rate | Habitat Migration? |
|---|---|---|---|
| 1 | Low () | NOAA Int. Low () | Restricted () |
| 2 | High ( ) | NOAA Int. Low () | Restricted () |
| 3 | Low () | NOAA Int. High ( ) | Restricted () |
| 4 | High ( ) | NOAA Int. High ( ) | Restricted () |
| 5 | Low () | NOAA Int. High ( ) | Allowed () |
| 6 | High ( ) | NOAA Int. High ( ) | Allowed () |
The major assumptions defining each run listed in the table above are explained in the left panel of each browser tab and fall into the following categories:
1) assumed low or high accretion rates by coastal habitats in the future;
— OR —
2) assumed intermediate low or high sea level rise rates as defined by NOAA et al. 2012 at the St. Petersburg NOAA tidal gage and supported through the Tampa Bay Climate Science Advisory Panel (2015);
— OR —
3) assumed either a restriction to coastal habitat migration by further protecting currently developed uplands or an allowance of coastal habitat migration to occur into undeveloped or "softly" developed uplands in the future.
— OR —
Furthermore, the left panel will provide a summary of the change in habitat extent (hectares) and the expected "sequestration" potential of coastal habitats (net green house gas stored in soils or plant tissues) based on the specific model run assumptions through 2100. The main map panel will depict the spatial distribution and transition of habitats throughout the bay over the 2007 – 2100 model run period.
- Symbols used in this story map are courtesy of the Integration and Application Network, University of Maryland Center for Environmental Science (ian.umces.edu/symbols/).
- Data and source code used to generate the interactive graphs on this website can be obtained from: https://github.com/esherwoo77/tbbca_water_atlas.
