The Sundarban mangrove forest covers 10,000 square kilometres of land and water in the Ganges Delta, straddling the India-Bangladesh border. It is a vitally important ecosystem, not just for the people, wildlife and plants that depend on it, but for the planet. Studies show that mangroves absorb and store – sequester – up to four times as much carbon dioxide as other tropical rainforest species, so they are a vital weapon in the global battle against climate change. Recent study shows that the Sundarbans sequester an estimated 360 million tonnes of CO2.