source-library/climate_change/sea_level_rise.md

Sea Level Rise

Climate change causes floods, natural disasters, and puts homes underwater

• National Ocean Service
  • Why Climate change effects sea levels
    • oceans warm due to an increasing global temperature, causing seawater to expand and take up more space in the ocean basin and causing a rise in water level.
    • melting of ice over land, which adds water to the ocean.
• National Oceanic and Atmospheric Administration: Lindsey 18
  • “The rising water level is mostly due to a combination of meltwater from glaciers and ice sheets and thermal expansion of seawater as it warms.”
  • Scope: In the United States, almost 40 percent of the population lives in relatively high population-density coastal areas, where sea level plays a role in flooding, shoreline erosion, and hazards from storms.
    • Globally, 8 of the world’s 10 largest cities are near a coast, according to the U.N. Atlas of the Oceans.
  • Sea levels have been continuously rising and put these areas under threat:

• Climate Central Executive Report: Strauss et al. 12
  • Climate change sea level impact
    • raised sea level about eight inches since 1880
    • the rate of rise is accelerating
    • Scientists expect 20 to 80 more inches this century, a lot depending upon how much more heat-trapping pollution humanity puts into the sky
    • This study makes mid-range projections of 1 to 8 inches by 2030, and 4 to 19 inches by 2050, depending upon location across the contiguous 48 states.
  • Climate change flooding impact
    • Rising seas dramatically increase the odds of damaging floods from storm surges.
    • For more than two-thirds of the locations analyzed (and for 85% of sites outside the Gulf of Mexico), past and future global warming more than doubles the estimated odds of “century” or worse floods occurring within the next 18 years
  • Impact on homes
    • At three quarters of the 55 sites analyzed, century levels are higher than 4 feet above the high tide line.
    • Across the country nearly 5 million people live in 2.6 million homes at less than 4 feet above high tide.
    • In 285 cities and towns, more than half the population lives on land below this line, potential victims of increasingly likely climate-induced coastal flooding.
    • 3.7 million live less than 1 meter above the tide.
    • About half of this exposed population, and eight of the top 10 cities, are in the state of Florida. About $30 billion in taxable property is vulnerable below the three-foot line in just three counties in southeast Florida.