How does global warming impact sea levels globally?

The rise in global sea levels is primarily caused by two main factors related to global warming. First, as the temperature of the planet increases, polar ice sheets and glaciers melt, contributing to higher ocean water levels. Second, warmer temperatures cause seawater to expand, a phenomenon known as thermal expansion. Both of these processes work in tandem to increase the volume of water in the world's oceans, leading to rising sea levels.

In contrast, the other options do not accurately reflect the relationship between global warming and sea levels. The assertion that global warming has no effect on sea levels is incorrect, as extensive scientific data shows a clear correlation between rising global temperatures and increased sea levels. Similarly, the idea that it causes sea levels to fall is contrary to the observed trends; in fact, sea levels are consistently rising. Lastly, stating that global warming only affects coastal regions overlooks the fact that rising sea levels pose threats far beyond coastal lines, impacting ecosystems, human settlements, and infrastructure globally. Thus, the correct answer acknowledges the significant and well-documented rise in sea levels due to global warming.