This heating up has caused the melting of the ice caps at the poles (Gore, 2006). This has several effects on the earth. First, it causes the rise of the ocean level. Glacial melting would contribute to about 230 feet rise in the ocean level if it were to happen at once (NCDC, 2008). Sea levels have risen by an average of 1.88mm per year since 1961 but have increased to 3.1mm per year from 1993. These figures seem small but if the ocean rises by just 3 feet, lower Manhattan could be submerged and sections of Miami would be lost. In Bangladesh and India, close to 23 million people live within this elevation of three feet (IPCC, 2007). That level of population displacement and loss of property would have serious economic and social effects.