What is a major concern related to rising sea levels?

The concern regarding the encroachment of salt water into freshwater supplies is significant in the context of rising sea levels. As sea levels rise, coastal areas are particularly vulnerable to saltwater intrusion. This can occur when the natural barrier that typically separates saltwater from freshwater becomes compromised, leading to increased salinity in freshwater aquifers and rivers.

This intrusion can have severe consequences for drinking water sources, agriculture, and local ecosystems that depend on freshwater. It can impair the ability of communities to access clean drinking water, negatively impact crop production by salinizing soils, and disrupt the habitats of various freshwater species. In regions where freshwater resources are already scarce, the impact of saltwater encroachment can amplify existing challenges and pose significant risks to public health and food security.

In contrast, the other options do not directly address the primary and immediate concerns associated with rising sea levels in the same way. Decreased biodiversity and sedimentation can be impacts of various environmental changes, but they are not as directly related to the immediate and severe implications of freshwater supply contamination caused by saltwater encroachment. The notion that rising sea levels would lead to more land available for agriculture is generally misleading, as inundation of coastal areas typically results in loss of land rather than