From Carbon Sink to Carbon Source
When coastal ecosystems degrade, centuries of stored carbon is released
Your Progress
Section 3 of 5The Double Climate Penalty
Blue carbon degradation creates a dual climate impact: lost sequestration capacity plus immediate carbon release from disturbed sediments.
When mangroves are cleared or salt marshes drained, anoxic sediments are exposed to air. Oxygen floods in. Microbes that were dormant for decades suddenly activate, decomposing centuries of accumulated organic matter within years. A hectare of destroyed mangrove can release 300+ tons of CO₂—equivalent to driving a car 1.3 million kilometers.
Since 1900: 25% of mangroves, 35% of salt marshes, 29% of seagrass beds have been destroyed globally.
Annual loss: 0.7-7% depending on ecosystem and region. At current rates, some areas face complete loss within decades.
Interactive Threat Impact Simulator
Select a threat and watch ecosystem health and carbon stocks decline over time
Coastal Development
Conversion to aquaculture, agriculture, ports, and urban infrastructure
Shrimp Farming
Mangrove clearing for shrimp ponds, particularly in Southeast Asia
Nutrient Pollution
Agricultural runoff and sewage causing eutrophication and die-off
Sea Level Rise
Submergence and erosion from accelerating sea level rise