Global land cover trajectories and transitions

Area of Science:

• Environmental Science
• Remote Sensing
• Sustainability Science

Background:

• Global land cover (LC) changes pose significant threats to sustainability.
• A comprehensive understanding of LC transitions, including magnitude, location, and timing, is lacking.
• Existing datasets often lack the fine resolution and temporal consistency needed for detailed analysis.

Purpose of the Study:

• To quantify land cover changes globally using a novel, high-resolution, time-consistent satellite dataset.
• To analyze the trajectories and error margins of land cover changes across various scales.
• To identify specific locations and countries experiencing significant land cover dynamics, particularly forest loss and urban growth.

Main Methods:

• Utilized a novel, fine-resolution, annually updated satellite-derived land cover dataset (1992-2018) for global analysis.
• Quantified land cover transitions at global, continental, and national scales.
• Compared observed land cover change trajectories against error margins derived from accuracy metrics.

Main Results:

• Observed land cover change trajectories were generally smooth and consistent, with most changes falling within dataset error margins.
• Urban land increase consistently exceeded error margins and showed a unidirectional transition.
• Top countries with high forest loss and urban growth were identified; most have stabilized forest losses, but urban expansion remained monotonic.

Conclusions:

• Urban land expansion is a significant and consistently underestimated global change.
• Fine-resolution, temporally consistent datasets are crucial for accurate land cover change assessment.
• Findings provide critical data for addressing sustainability challenges and supporting UN Sustainable Development Goals (SDGs).