Agence France-Presse: Some villagers use bamboo fencing. Others plant mangroves. And some do both to fight back against erosion transforming centuries-old communities on the Gulf of Thailand. Only a half hour drive south of Bangkok, coastal regions already show alarming signs of erosion: electricity poles, once on land, are submerged in parts of Bang Khun Thien, a district on the outskirts of Bangkok. Kongsak Lerkngam, who lives in Bang Khun Thien and works on an erosion protection initiative in six …