What is the primary reason global warming is causing sea levels to rise?

The primary reason global warming is causing sea levels to rise is due to the combination of melting ice and thermal expansion of seawater. As global temperatures increase, polar ice sheets and glaciers are melting at an accelerated rate, releasing freshwater into the oceans. This contributes directly to rising sea levels.

Additionally, as water warms, it expands. This thermal expansion occurs because the molecules in water move more vigorously at higher temperatures, taking up more space and effectively causing sea levels to rise even further. The synergy of these two processes—melting ice contributing fresh water and warmer temperatures causing expanding water—underpins the significant rise in global sea levels associated with climate change.

Other choices are less relevant in the context of primary causes for sea level rise. For instance, while precipitation can influence water levels locally, it does not have the same direct impact on global sea levels as melting ice and thermal expansion. Similarly, changes in irrigation practices and the compression of ocean basins due to geological processes occur independently of the immediate effects of global warming on sea level.