New CUHK research reveals mangroves’ critical role in removing global coastal nitrogen pollution, termed “blue nitrogen.” Published in Earth’s Future, the global study estimates mangroves eliminate 870,000 tonnes of nitrogen pollutants annually, representing an ecosystem service worth more than US$8.5 billion. The findings highlight mangroves as vital natural infrastructure for water purification, carbon storage and building resilient, sustainable coasts.

Mangrove wetlands help with climate change by retaining carbon but the methane they emit counters the benefit. An international study shows the good being done by retention is reduced by emission to half over 20 years. And the balance is tipping the wrong way because of global warming and river discharge.