What are the primary causes of sea level rise?

• A. Increased rainfall and river flooding
• B. Thermal expansion and melting of glaciers
• C. Earthquake activity underwater
• D. Changes in ocean currents

Answer: (B)

The primary causes of sea level rise are thermal expansion of seawater and the melting of glaciers and ice sheets. When ocean water warms, it expands, causing sea levels to rise. This thermal expansion is a significant factor in areas experiencing higher temperatures due to climate change.

Additionally, glaciers and polar ice sheets are melting at an accelerated rate due to rising global temperatures. As these large masses of ice melt, they contribute freshwater to the oceans, further elevating sea levels. The combination of these two processes accounts for the majority of observed sea level rise, particularly in the context of recent climatic changes. Understanding these mechanisms is crucial for addressing the impacts of climate change and preparing for future challenges related to coastal management and flood risks.

The other options relate to different phenomena; increased rainfall and river flooding can impact local sea levels temporarily but are not primary drivers of global sea level rise. Earthquake activity underwater primarily affects local topography without long-term impacts on global sea levels. Changes in ocean currents can influence local sea levels but do not contribute significantly to the overall rise in the global mean sea level.