Anthropogenic causes involve human activities and is how most oil enters the ocean. The ways oil spills anthropogenically in the ocean are because of drilling rigs, pipelines, refineries, and wars. Anthropogenic spills are more harmful than naturals spills, as unlike natural spills, they leak about 210 million gallons of petroleum each year. Also, anthropogenic spills cause abrupt changes to ecosystems with long-term effects and even longer remediations.
