Overview of Impacts
Climate change primarily affects ocean levels by causing sea levels to rise through two main processes: the melting of land-based ice and the thermal expansion of seawater. As global temperatures increase due to greenhouse gas emissions, glaciers and ice sheets on land melt, adding water to the oceans. Simultaneously, warmer ocean temperatures cause water molecules to expand, increasing the volume of seawater without adding more mass.
Key Mechanisms
The melting of ice includes contributions from polar ice sheets in Greenland and Antarctica, as well as mountain glaciers worldwide. Thermal expansion occurs because water density decreases with rising temperatures; for every degree Celsius increase, seawater expands by about 0.1% in volume. These effects are interconnected, as warmer air and oceans accelerate ice melt, creating a feedback loop that amplifies sea level rise.
Practical Example: Antarctic Ice Shelf Collapse
Consider the Larsen B ice shelf in Antarctica, which collapsed in 2002 after warming temperatures thinned the ice. This event released vast amounts of freshwater into the Southern Ocean, contributing to local sea level rise and altering ocean currents. Similar collapses, like those observed in recent years, demonstrate how climate-driven ice loss directly translates to measurable increases in global ocean levels, with projections estimating up to 1 meter of rise by 2100 if emissions continue unchecked.
Global Importance and Applications
Rising ocean levels threaten coastal ecosystems, infrastructure, and populations, leading to increased flooding, erosion, and saltwater intrusion into freshwater supplies. This impacts billions living near shores, necessitating adaptive measures like sea walls and mangrove restoration. Understanding these effects is crucial for international policies, such as the Paris Agreement, which aim to mitigate emissions and limit future rise to sustainable levels.