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CO2 emissions from degraded mangrove forests set to increase by 50,000% 

Annual carbon emissions from degraded mangrove forests could escalate by nearly 50,000% by the end of the century. This startling projection comes from a recent study led by Montclair State University.

The surge in emissions will primarily take place across degraded mangrove forests in regions like southern India, southeastern China, Singapore, and eastern Australia.

These mangrove forests are crucial for carbon storage, particularly in their soil. Despite their importance, human development activities have led to a noticeable decline in these vital carbon stocks.

Massive loss of mangrove carbon stocks 

Over the past two decades, the conversion of mangrove forests to agricultural, aquacultural, and urban areas has resulted in the loss of 158.4 million tons of global mangrove carbon stocks

This loss equates to the carbon emissions generated by transporting the entire population of the United States from New York to London by air, illustrating the substantial environmental impact of such degradation.

Studying degraded mangrove forests

The investigation, led by Professor Jennifer Krumins of Montclair State University, together with PhD candidates Shih-Chieh Chien and Charles Knoble, aimed to examine the correlation between human population density and soil carbon stocks in urban mangrove forests. 

The research contributes to understanding the global carbon budget’s dynamics concerning these ecosystems.

Critical new insights 

The findings highlight a concerning trend: in areas with a population density of 300 people/km2 – comparable to the population density of the UK or Japan – the carbon stored in mangrove soils near populated regions is about 37% less than in isolated mangrove forests. 

Furthermore, the study estimates that the current annual rate of carbon emissions from mangrove loss is 7.0 Teragrams, a figure that is expected to increase to 3,392 Teragrams by the end of the century, in line with current predictions and increasing population densities.

Broader implications

Mangrove forests, which occupy roughly 0.1% of the Earth’s land surface, are disproportionately significant in their carbon storage capability, especially within their soils. These ecosystems are known to contain three to four times the mass of carbon typically found in other forest types, making them a critical component of the global carbon cycling process.

“This work underscores the importance of protecting existing mangroves, especially in areas with high population density,” Krumins said. 

“Mangrove forests are critical to the regulation of carbon sequestration, and it is important that we protect them. The first step is to understand the impact of human populations and activities on mangrove forest carbon stocks.” This call to action emphasizes the need for concerted efforts to safeguard these vital ecosystems for future generations and the planet’s overall health.

‌Degraded mangrove forests 

Degraded mangrove forests are ecosystems that have suffered loss in their structure, function, and biodiversity due to various stressors such as pollution, deforestation, climate change, and overexploitation. These stressors lead to significant changes in the mangrove ecosystem, including reduced tree height and density, lower species diversity, and compromised soil quality. 

Impacts of degradation 

The degradation of mangroves impacts not only the flora and fauna that depend on these ecosystems for habitat but also the human communities that rely on them for wood, food, and protection against coastal erosion and storms.

Valuable ecosystems

The roots of mangrove trees play a crucial role in sediment stabilization and act as a buffer against storm surges and tsunamis. When mangrove forests are degraded, the effectiveness of this natural barrier diminishes, leaving coastal areas more vulnerable to natural disasters. 

Carbon sinks

Furthermore, mangroves are efficient carbon sinks, storing large amounts of carbon in their biomass and soil. Degradation leads to the release of this stored carbon, contributing to greenhouse gas emissions and climate change.

Restoration and conservation

Restoration and conservation efforts are essential to reverse the degradation of mangrove forests. These efforts may include reforestation projects, protection laws to prevent further cutting and pollution, and sustainable management practices that support the livelihoods of local communities while preserving the mangrove ecosystems. 

Successful restoration not only involves planting mangroves but also ensuring that the conditions necessary for their survival, such as appropriate hydrology and protection from further disturbances, are met.

The study is published in the journal Environmental Research Letters

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