Global sea level rise continues to accelerate

In the United States alone, almost 40 percent of the population lives in relative high-population-density coastal areas.

According to a new report from NOAA, global sea level has risen 21-24 cm (8-9 inches) since 1880. A third of that increase has come in the past 25 years. In 2018, the average global sea level was 8.1 cm (3.2 inches) higher than it was in 1993.

Global sea level rise since 1880. Image courtesy NOAA.

The prime sources for sea level rise are meltwater from glaciers and ice sheets along with the thermal expansion of seawater as it warms.

Image courtesy NOAA.

Sea level is typically measured by tide gauges and satellite altimeters, according to the NOAA Climate.gov report.

The rate of sea level rise during the 20th century as a whole was 1.4 mm per year (0.06 of an inch per year). However, from 2006-2015, the rate of global sea level rise was 3.6 mm per year (0.14 of an inch per year).

High tide flooding is now 300 percent to 900 percent more frequent than it was 50 years ago along many coastal locations in the U.S.

Key excerpt from NOAA......Past and future sea level rise at specific locations on land may be more or less than the global average due to local factors: ground settling, upstream flood control, erosion, regional ocean currents, and whether the land is still rebounding from the compressive weight of Ice Age glaciers. In the United States, the fastest rates of sea level rise are occurring in the Gulf of Mexico from the mouth of the Mississippi westward, followed by the mid-Atlantic. Only in Alaska and a few places in the Pacific Northwest are sea levels falling, though that trend will reverse under high greenhouse gas emission pathways.