Efforts to mitigate tropical deforestation overlook coconut palm (Cocos nucifera L.) plantations on atolls—low island ecosystems that represent the most common landforms in the Pacific basin. Coconut palms have a deep history in the Pacific and were planted extensively over the last two centuries to meet the surging demand for coconut oil exports. But despite wide interest in the global footprint of palm crops, the distribution of coconut palms on Pacific atolls has remained unknown. We applied a supervised machine learning classifier to satellite imagery to produce 2 m resolution vegetation maps of 235 of 266 Pacific atolls. Despite the abandonment of many plantations in recent decades, we find that coconut palms surpass native broadleaf trees in terms of canopy area: coconut presently covers 58.3% of the mapped atolls’ total forested area and 24.1% of their total land area. 51.2% of these coconut canopies occur in monocultures indicative of plantation agriculture and drastic ecological changes. Even among atolls with climates equally suitable for coconut palms, coconut canopy coverage is 32.1 percentage points greater on those that historically exported coconut products, demonstrating the significant and persistent effects of plantations on forest compositions in the tropical Pacific. Coconut palms are most dominant on large, wet islands, reflecting their high rates of water use and thus their potential to deplete critical groundwater resources. The spread of coconut plantations also came at the expense of native vegetation critical for wildlife habitat, nutrient cycling, and soil formation. The severe environmental impacts of coconut plantations urge ecosystem management in a region uniquely exposed to climate change.
