Sea Level Rise Projections Revised Upward

Citing rapid melting at the poles, NOAA says global sea levels will rise faster than previously projected. This increases the flood risk for many coastal communities in the United States.

The agency’s new report, “Global and Regional Sea Level Rise Scenarios for the US”, updates a 2012 study and outlines a range of possible situations. Through 2100, it projects a global sea level rise of at least 1 foot on the low end to as high as 8 feet under a worst case scenario. The previous projections were estimated to be 4 inches and 6.6 feet, respectively.

On a regional level, from Virginia to Maine, sea-level rise is expected to be 1 to 1.6 feet greater than the global average. This is because the land is slowly sinking at the same time the water is rising. This precarious combination will intensify both high tide flooding and any storm surge events in the region.

The two main drivers of sea level rise are thermal expansion – a process in which water expands as it warms – and the melting of land-based ice. Both are the result of rising global temperatures.

The exact amount of sea level rise will depend on how much greenhouse gases are added to the atmosphere in the near future and the rate at which the massive ice sheets in Greenland and Antarctica melt.

Relative sea level trends based upon full record (>30-year period of record in all cases) measured and published for NOAA tide gauges through 2015. Credit: NOAA

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About Melissa Fleming

Melissa Fleming is an environmental communicator and visual artist working at the intersection of art and science. She is passionate about exploring, learning, and sharing information about the natural world. She has presented her interdisciplinary work in a variety of mediums at venues and conferences around the world.