Title: Causes of Sea Level Rise: What the Science Tells Us | Union of Concerned Scientists
Headings: Causes of Sea Level Rise
Causes of Sea Level Rise
What the Science Tells Us
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Content: Human activities, such as burning coal and oil and cutting down tropical forests, have increased atmospheric concentrations of heat-trapping gases and caused the planet to warm by 1.4 degrees Fahrenheit since 1880. Rising temperatures are warming ocean waters, which expand as the temperature increases. This thermal expansion was the main driver of global sea level rise for 75 - 100 years after the start of the Industrial Revolution, though its relative contribution has declined as the shrinking of land ice has accelerated. Land ice—glaciers, ice caps, and ice sheets—is shrinking at a faster rate in response to rising temperatures, adding water to the world's oceans. As the rate of ice loss has accelerated, its contribution to global sea level rise has increased from a little more than half of the total increase from 1993 - 2008 to 75 - 80 percent of the total increase between 2003 - 2007. Roughly a third of the US population—more than 100 million people—live in coastal counties. Coastal states with large areas of low-lying land, including Louisiana, Florida, North Carolina, California, and South Carolina, are particularly vulnerable to rising seas and coastal storm surges. The risks to coastal states include: Shoreline erosion and degradation. Rising sea levels allow waves to penetrate further inland, even during calm conditions, increasing the potential for erosion.