At present， the academic circles have made two opposite predictions on the future trend of climate change， in which the trend of global warming has a great influence on the world geopolitics and its security. Climate warming accelerates the thaw of glaciers in the Arctic， and the extension of Arctic navigation time makes the Russian north line face the epoch-making greater safety pressure， which is to change the original three-direction defense structure without threat from the north. The extending of Arctic navigation time will greatly change the logistics layout of Eurasian continent， the Arctic coastal states， and even the India Ocean and Pacific Ocean. Meanwhile， it will partially transfer the geopolitical role of Suez Canal to the Bering Strait， and the focus of geopolitical conflict among world's major powers will move from the south to the North Pacific. The rise of strategic position of the north of Russian and the east of Japan in the global geopolitical pattern will make China a strategic rear area for Russia and Japan. Then the position of Taiwan region will decline in the geostrategic consideration of nations such as United States， and Japan， and China's eastern security border will be further extended to the east. As a result， the reunification of Taiwan and the solution of the South China Sea issue will be feasible. On the other hand， the rising sea level will make the sea water flow into the hinterland of China， which will increase the strategic depth of the eastern coast of China， and China's coast defense is to confront greater pressure．