Poor countries are less able to spend big to fix some of the looming problems. Vietnam currently exports $2.9 billion worth of rice every year, but that trade is increasingly in danger. According to the Asian Development Bank, Vietnam's rice production could decline dramatically as rising sea levels submerge tens of thousands of hectares of cropland by the end of the century. Because Vietnam's rice industry depends on low-lying farm areas in the Mekong and Red River deltas, even relatively small increases in sea level could have disastrous consequences for the country. This poses a food security threat as well, given that Asian nations rely heavily on rice to feed their masses.