Ocean warming is a serious symptom of the overall process of global warming. Since 1971, over ninety percent of the warming of the Earth's climate has occurred in the oceans, accelerating the melting of the polar ice caps and threatening coastal and low-lying areas with future flooding.
A vast majority of scientists have demonstrated that global warming is being caused by the increased concentration of greenhouse gases due to human activity. Oceans are slower to warm than the atmosphere, but ocean temperatures have risen 0.18 degrees Fahrenheit to depths of 2300 feet, where most marine lives. As the ocean water heats up, it expands. This will lead to a rise in sea levels across the globe, inundating coastal areas, producing shoreline erosion and storm surges.
Another effect of warmer oceans will be more powerful storms. Hurricanes, for example, draw their strength from warm water. Warmer oceans will allow such storms to intensify. Hurricanes Katrina and Sandy are believed to be portents of such stronger storms.
Sea level rise will force millions of human beings around the world to relocate inland, and may threaten extinction. Some scientists fear that rising ocean temperatures will interrupt the ocean conveyor system of global currents that regulate Earth's temperature. Such a catastrophe could wipe out all life on Earth.