Karachi's mangroves, defence against storms and tsunamis, threatened

Space Daily via AFP: Thick mangroves have long protected Karachi, southern Pakistan's sprawling metropolis, from battering by the Arabian Sea, but pollution, badly managed irrigation and years of illegal logging have left this natural barrier in a parlous state.

Experts fear that loss of the natural barrier formed by the mangroves could put the city of nearly 20 million people at greater risk from violent storms and even tsunamis. Close to Karachi, the mighty Indus river ends its long journey from the Himalayas in the sea.

The river delta is home to the shimmering green mangrove, a delicate ecosystem that thrives in the mingled salt and fresh water....But the mangrove is a shadow of its former self -- from 600,000 hectares in the early 20th century now barely 130,000 hectares remain, according to marine biologist Mohammad Moazzam Khan.

The rest has fallen victim to illegal loggers, pollution from nearby industry and changes to the river flow caused by irrigation upstream on the agricultural plains of Sindh and Punjab provinces. The fishermen, who make a livelihood from the fish and shellfish that shelter in the mangroves, have warned about their decline for years....

NASA image of the Indus River delta