LUCC-based carbon emission simulation under multiple-scenarios in the Guangdong-Hong Kong-Macao Greater Bay Area

• Integrates FLUS and STIRPAT models to simulate future land carbon emissions. • GBA’s carbon sequestration accounts for less than 5% of its carbon emissions. • Cities are categorized into 4 clusters by their peaking timelines and emission levels. • MDS better supports the study area’s sustainable development. Rapid population and economic growth intensify carbon emissions and degrade land carbon sinks. While existing research predominantly focuses on urban energy emissions, systematic studies addressing comprehensive land-carbon interactions in China’s key urban agglomerations remain lacking. This research integrates Markov-FLUS and extended STIRPAT models to simulate 2021–2040 land-use and carbon emissions in the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) under low-carbon, moderate, and extensive development scenarios. Key findings: The moderate development scenario achieves the most balanced land-use changes, whereas other scenarios exhibit extreme shifts in specific land types. Significant land-use transformations predominantly occur in ecologically sensitive areas across all scenarios, particularly in peri -urban zones and administrative boundaries. The GBA will achieve carbon peaking by 2030 under low-carbon (470.3 million tons) and moderate scenarios (520.1 million tons), but experience 1 year postponement under extensive development scenario (563.3 million tons). Cities are categorized into 4 groups based on their peaking timelines and emission levels. Land-based carbon sequestration remains substantially lower than emissions throughout the region (less than 5 %). Therefore, the core of decarbonization development in the GBA resides in controlling carbon source emissions. Achieving low-carbon and sustainable development in the GBA requires comprehensive consideration of land circulation changes and green urban development.