The Rising Seas
Global sea levels over the past 2,000 years or so have changed very little; however, starting in the 20th century, the worlds oceans have started to have a more consistent rise. Since 1993, the amount of global sea-level rise (0.12 inches per year) has doubled compared to the long-term trend between 1880-2013 (0.06 inches per year).
The primary factors for the acceleration of global sea-level rise has been the increased melting of land-based glaciers and ice sheets and the thermal expansion of ocean water due to warming waters (increasing ocean heat content), which are both directly caused by climate change.
Keep in mind, sea-level rise is not uniform across the world. Some regions are experiencing a significant rise in sea level, while others are experiencing a much slower rise. There are even some pockets in the world that are experiencing a slight decrease in sea level, but this is a very small percentage. The image below shows the varying changes (cm's) in sea height from 1992-2019.
The relative sea level has not risen uniformly due to regional and local in-land movement and long-term changes in coastal circulation patterns.
The primary impact of this widespread sea-level rise has been the increase in coastal flooding along low-lying coastal areas.
The image below shows where sea levels have been rising the most along the United States coastlines since 1960. Note that some locations along the West Coast have experienced a slight drop in sea level.
The impact from rising sea levels is pretty clear, especially along the East coast, with the significant uptick in the frequency of coastal flooding. Small storms that would not have produced any flooding back in the middle of the 20th century are frequently causing flooding problems along exposed coastlines. In Florida, it no longer takes a storm to produce coastal flooding, sometimes just high tide itself.
