Assessing changes in mangrove forest cover and carbon stocks in the Lower Mekong Region using Google Earth Engine

Abstract

The Lower Mekong Region (LMR) faces significant loss of mangrove forests, yet limited studies have explored this decline in the region. Here, we employ Google Earth Engine and Landsat satellite imagery to assess changes in mangrove forest cover across Myanmar, Thailand, Vietnam, and Cambodia between 1989 and 2020, with a five-year interval. Accordingly, we estimated carbon stock changes due to changes of forest cover. Our analysis yielded an overall average accuracy of 92.10% and an average kappa coefficient of 0.89 across the four countries. The findings reveal a 0.9% increase in mangrove area in Myanmar, 2.5% in Thailand, and 1.3% in Cambodia, while Vietnam experienced a 0.2% loss annually between 1989 and 2020. Carbon stocks in mangrove forests were estimated at 577.0 ​Tg of carbon or TgC, 250.0 TgC, 61.6 TgC, and 269.0 TgC in 1989 for Myanmar, Thailand, Cambodia, and Vietnam respectively, and increased to 736.0 TgC, 443.0 TgC, 86.7 TgC, and 254 TgC in 2020. Increase in mangrove areas resulted in carbon removals of 42.8 TgCO₂ year⁻¹ over the same period above. Depending on policies in these respective countries, such carbon removals could be used to claim for result-based payment under the REDD ​+ ​scheme of the United Nations Framework Convention on Climate Change.