How is climate change expected to influence sea-level rise and coastal erosion?

• A. Thermal expansion and ice melt raise sea level; climate change increases storm intensity and frequency, accelerating erosion
• B. Sea level rise is caused solely by tectonic activity
• C. Sea level will stay constant with more rainfall
• D. Erosion is not influenced by climate

Answer: (A)

Climate warming causes sea level rise through two main mechanisms—thermal expansion of seawater as it warms and the addition of freshwater from melting land-based ice—while it worsens coastal erosion by increasing storm intensity and wave energy. As ocean water warms, it expands, taking up more space. At the same time, melting mountain glaciers and the ice sheets of Greenland and Antarctica add water to the oceans, raising the overall sea level. When sea level is higher, waves and storm surges can reach further inland, and stronger, more frequent storms churn more energy into the coast, speeding up erosion and transporting sediment away from shorelines. The other statements miss these key processes: sea level rise is not caused mainly by tectonic activity, it is not constant with more rainfall on a global scale, and erosion is indeed influenced by climate through changes in storminess and wave action.