The above graph shows cumulative changes in sea level for the world's oceans since the year 1880. Data is based on a combination of long-time tide gauge measurements and recent satellite measurements.
The image shows average absolute sea level change, which refers to the height of the ocean surface, regardless of whether nearby land is rising or falling. Keep in mind that on average, the ocean floor has been gradually sinking since the last Ice Age peak, some 20,000 years ago.
After a period of roughly 2,000 years of little change, global average sea level rose throughout the 20th century and the rate of change has accelerated in recent years.
When averaged over all the world's oceans, absolute sea level increased at a rate of 0.07 inches per year from 1880 - 2011. From 1993-2011, average seal level rose at a rate of 0.11 to 0.13 inches per year.
Relative sea level rose along much of the U.S. coastline between 1960 - 2012. The figure above shows parts of the east coast and gulf coast have seen rises reach 8 inches, as indicated by the red arrows. Notice the blue arrows along Oregon and Washington, showing a fall in relative sea level. Data shows absolute sea level off of the Northwest coast has risen, but land elevation rise has outpaced the changing sea level.
Local changes in land movement and long-term changes in coastal circulation patterns have played a role in other world coastal areas showing a decrease in relative ocean level.
This study is courtesy of the United States Environmental Protection Agency.
Meteorologist Rod Hill, follow me @