The impact of climate change will cost the two economic hubs, Hai Phong City and Dong Nai province, 1.25 percent of their GDP each year, a study by the Institute of Hydro-meteorological and Environmental Sciences has found.

The northern city of Hai Phong is on the coast while the souther province of Dong Nai is very near the sea, and a major percentage of the populations in both places depend on agriculture, including aquaculture, for a living. Flooding and seawater intrusion in rivers will ravage agriculture.

The institute's two-year study titled "Sea-level rise scenarios and possibilities of damage limitation", which it released on Dec. 23, warned that 1.6 percent of the country's land area would be flooded in case of a 50cm rise in sea levels. Rises of 75cm and 100cm will see the percentage rise to 3.1 and 5.3 percent.

A total of 33 provinces would be affected.

The Cuu Long (Mekong) Delta would be the worst affected by floods area, with the most vulnerable being the provinces of Kien Giang, Ca Mau, Hau Giang and Soc Trang.

In the central region, Thua Thien-Hue province would be affected by erosion at the sea mouth at Thuan An and Canh Duong.

Coral layers off the Ha Tinh province coast would be devastated.

The study estimates 4.5 million people to be affected, including 3.3 million in the Cuu Long Delta and 400,000 in the Song Hong (Red River) Delta.

Seawater intrusion would be widespread, reaching a maximum of 44km in the Kinh Mon River in northern Hai Duong province.

Dr Duong Hong Son, the institute's director, said sea levels are already rising 3mm each year and it is set to accelerate in the next few decades.

Each province should have its own plans for risk mitigation, he added./.