In November 2001, the leader of the Pacific island nation of Tuvalu said in a statement that their efforts to combat rising sea levels had failed. In 2002, the entire country emigrated

In the past 50 years, greenhouse gases such as carbon dioxide emitted by humans in the process of production and life have increased dramatically, causing global temperatures to rise and disasters such as droughts and floods to become frequent. The emitted chlorofluorocarbons destroy the ozone layer at high altitudes, causing increased ultraviolet radiation from the sun on the ground, thereby endangering human health. The main reason why Tuvalu became the world's first "environmental refugee" country is that the increase in carbon dioxide emissions has caused the earth to continue to warm, the glaciers at the poles have melted, and sea levels have risen.

So choose: B.