1:45 PM - 2:00 PM
[AHW18-11] Wetlands Restoration – A Nature-Based Solution to Combat Climate Change – Challenges and Opportunities
★Invited Papers
Keywords:Wetlands, Carbon Sequestration, Nature-Based Solution, Greenhouse gas Emissions, Carbon dioxide removal (CDR), Climate Change
Achieving the temperature targets of the UNFCCC Paris Agreement through emissions abatement alone is currently looking increasingly infeasible as global emissions continue to rise. Accordingly, this necessitates a step change in carbon dioxide removal (CDR) to sequester substantial volumes of existing atmospheric greenhouse gases. Among other technologies natural carbon removal strategies could provide cost-effective negative emissions solutions (nature-based solution). Examples include allowing forests to regrow, restoring coastal wetlands, and switching to restorative agricultural practices. These ecosystems reduce climate change by capturing CO2 from the air and sequestering it in plants, soils, and sediments. They also provide a wide range of other important benefits, such as cleaner air and water, economic benefits, and increased biodiversity.
Although wetlands cover only 5-8% of the Earth's land surface, they are disproportionately active sites in the global C cycle - an issue of significant importance for Earth’s radiative balance. The high rates of plant productivity and low rates of organic matter decomposition in these ecosystems make C accumulation rates in wetland soils very high and give these ecosystems the capacity to be major C sinks. A large body of work suggests that over centuries, and geologic timescales, wetlands commonly exhibit net cooling effects because of their effective C sequestration. However, wetlands also produce and emit GHG, such as CH4, through organic C decomposition processes. Because CH4 is such a potent GHG, it disproportionately influences radiative forcing and could therefore offset C storage in wetland soil, rendering these ecosystems a net source of C. Indeed, while wetlands exhibit negative net radiative forcing on longer timescales due to net C burial, evidence suggests that on shorter timescales relevant to human activities, the radiative forcing is substantially affected by CH4 emissions, reducing the efficacy of C sequestration by these systems. One of the most efficient net C sequestration wetland systems are coastal vegetated habitats (i.e., mangrove, marsh, and seagrass environments) which are incredibly efficient at capturing and storing C. C storage in coastal wetland soil accounts for 50% of the C stored in all marine sediments. Knowing the rate of C uptake by soils and the processes that determine this rate, as well as the magnitude of and controls on lateral C export and emissions of GHG from wetlands are among the critical aspects still to be answered. However, the C balance in coastal wetlands is notoriously difficult to predict because of the marked spatial heterogeneity in vegetation and hydrology at any given wetland site, and differences across wetland systems. The lack of clear understanding of the processes underlying C dynamics in coastal wetlands limits the ability to include these systems in process-based ecosystem or predictive Earth system models and hence limits our ability to assess the capacity of these systems to serve as nature-based C sequestration systems that could contribute to one of the current global challenges – combating climate change and adapting to related impacts.
We will present research efforts to assess C dynamics in costal wetlands in California, their net C sequestration potential, including monitoring of greenhouse gas emissions and lateral C loss and discuss challenges and opportunities. These data are needed informing and optimizing the many approaches for wetland restoration and management and measuring and verifying the net carbon removal and/or storage and for determining controlling processes and the geo-bio-spatial constraints in deploying these solutions at large scale. This information is also needed to better understand and design policy instruments to further promote the development and deployment of these solutions in an equitable and just way.
Although wetlands cover only 5-8% of the Earth's land surface, they are disproportionately active sites in the global C cycle - an issue of significant importance for Earth’s radiative balance. The high rates of plant productivity and low rates of organic matter decomposition in these ecosystems make C accumulation rates in wetland soils very high and give these ecosystems the capacity to be major C sinks. A large body of work suggests that over centuries, and geologic timescales, wetlands commonly exhibit net cooling effects because of their effective C sequestration. However, wetlands also produce and emit GHG, such as CH4, through organic C decomposition processes. Because CH4 is such a potent GHG, it disproportionately influences radiative forcing and could therefore offset C storage in wetland soil, rendering these ecosystems a net source of C. Indeed, while wetlands exhibit negative net radiative forcing on longer timescales due to net C burial, evidence suggests that on shorter timescales relevant to human activities, the radiative forcing is substantially affected by CH4 emissions, reducing the efficacy of C sequestration by these systems. One of the most efficient net C sequestration wetland systems are coastal vegetated habitats (i.e., mangrove, marsh, and seagrass environments) which are incredibly efficient at capturing and storing C. C storage in coastal wetland soil accounts for 50% of the C stored in all marine sediments. Knowing the rate of C uptake by soils and the processes that determine this rate, as well as the magnitude of and controls on lateral C export and emissions of GHG from wetlands are among the critical aspects still to be answered. However, the C balance in coastal wetlands is notoriously difficult to predict because of the marked spatial heterogeneity in vegetation and hydrology at any given wetland site, and differences across wetland systems. The lack of clear understanding of the processes underlying C dynamics in coastal wetlands limits the ability to include these systems in process-based ecosystem or predictive Earth system models and hence limits our ability to assess the capacity of these systems to serve as nature-based C sequestration systems that could contribute to one of the current global challenges – combating climate change and adapting to related impacts.
We will present research efforts to assess C dynamics in costal wetlands in California, their net C sequestration potential, including monitoring of greenhouse gas emissions and lateral C loss and discuss challenges and opportunities. These data are needed informing and optimizing the many approaches for wetland restoration and management and measuring and verifying the net carbon removal and/or storage and for determining controlling processes and the geo-bio-spatial constraints in deploying these solutions at large scale. This information is also needed to better understand and design policy instruments to further promote the development and deployment of these solutions in an equitable and just way.