Authors: Dr. Arshad M. Khan and Meena Miriam Yust
The coastal waters by Wilmington, Delaware, the president’s home base, have risen a record 3 mm in the past year. Worse, the rate of increase is itself increasing portending a foot or more in the next century. It means a rebuilding of docks plus barriers to prevent serious tidal flooding.
The Virginia Institute of Marine Sciences (VIMS), affiliated with the College of William and Mary, has been collecting data on sea levels for the past 52 years. It released its latest annual report recently, noting sea level rising by historic amounts — as in the case of Wilmington — as well as the accelerating rate of increase.
There are 32 tide gauges placed along the US coasts all the way to Alaska. Maintained by the National Oceanic and Atmospheric Administration (NOAA), these measure levels every six minutes. Researchers at VIMS take a monthly average to avoid a skewed analysis due to unusual weather patterns like storms.
The Institute’s report presents sea level changes, assesses future trends, and tries to explain the increases or even decreases at particular localities. Sea level changes are relative to the adjoining land. For example, the rates are actually falling in Alaska but that is caused by shifting tectonic plates raising land and off-setting the sea level rise.
Researchers describe the persistent sea level rise as a “slow emergency” — not a storm that will be hitting tomorrow but trouble ahead and the report cards can help local authorities plan for the future.
Wetlands Watch works to preserve wetlands in Virginia’s coastal areas. Rising sea level is a particular concern because it is expected to affect most of the state’s coastal wetlands. Therefore in addition to policy advocacy, Wetlands Watch has developed Sea Rising Solutions, which helps in mapping out where flooding is likely.
Spreading the word about sea level rise and its consequences engages the whole community and motivates legislators and developers to adapt to the new norm and prepare ahead for a changing environment.
There is another problem with coastal areas: a gradual darkening of the sea water. It is serious for such a change in color and clarity poses a significant threat to marine life. The Coastal Ocean Darkening Project at the University of Oldenburg in Germany simulated the effects by filling huge metal vats with water and phytoplankton and hanging lamps above them to simulate sunlight. They then darkened the water using low, medium and high concentrations of a brown liquid extracted from peat to simulate decaying organic matter. The phytoplankton were all negatively affected but particularly in the vats with medium and high concentrations which blocked off more light. Also some phytoplankton were affected more than others.
The adverse consequences to the elemental base of the ocean’s food threatens marine species up the chain, and especially those relying on the phytoplankton types most affected. Moreover, reduced vision hinders those species, like fish, relying on vision to hunt, while not affecting those that do not, like jellyfish.
Why is the water darkening? One hint might be that environmental regulation of fertilizer use goes along with improvements in the Mediterranean, the North Sea and parts of the North American coast. And of course reducing global warming would decrease ice melt and subsequent sea level rise.