coastal cities

Photo by Noelle Anderson

Is sea level rise something we need to be concerned about right now? If you look at the data from the Union of Concerned Scientists, it seems far off somehow yet, we are seeing the water rise and cities and towns are talking about mitigation to protect vulnerable property. So what is going on? What action can we take?

Sea level rise, caused by human induced climate change, amplifies the effects of tidal height and storm surge associated with all coastal storms. A storm doesn’t need to be “super” to cause significant damage. Most people remember Hurricane Sandy. The iconic images of the massive storm taken by satellite; the bent and twisted frame of the drowned roller coaster sitting placidly in the surf just off the Jersey Shore; the flooded tunnels of the New York City subway system and lower Manhattan are hard to forget. Similarly, we shudder at the memory of New Orleans residents clinging to their roofs awaiting rescue by helicopters during Hurricane Katrina. Yet, we also tend to dismiss such happenings as anomalies. We call them “super storms “ or “100-year storms” and unless we were directly impacted, go on with our lives.

Because of warming seas from human induced climate change, scientists warn that 100-year storms are becoming more frequent. Coastal flood advisories and flood watches due to “astronomical tides” were in effect recently in locations from Key West to Maine, including Boston, Baltimore, Washington, DC, and other cities in between. In the southern part of Florida, a third night of flooding closed roads, flooded sidewalks and led to some of the most extensive tidal flooding they’d ever witnessed. Charlestown has seen consecutive days with road closure due to flooding and lives were lost due to rising waters. Last month’s king tide saw alligators swimming in flooded streets.

One constant piece of this phenomenon, the monthly ebb & flow of the tide, is just doing what it does, albeit with an extra kick when there is a king tide. With sea level rise, the highest tides are only getting higher, due to the thermal expansion caused by the increasing warm air and water and the flooding they bring is getting more frequent. Regardless of whether you live along the coast or in the nation’s heartland, the impact will be both economic and geographic.

Many of our most populous metropolitan areas are located where the ocean meets the land. In fact more than 100 million people live in coastal counties. These counties produce 42 percent of the US economy’s GDP. Besides being financial, military and government centers, these areas are home to the largest ports in our country. A quick glance at the list of the top five ports in the continental US, illustrates the vulnerabilities. They are located in Louisiana, Texas, New York/New Jersey, and account for billions of metric tons in movement of goods, both exports and imports, annually. In the past decade, each one has been impacted by a significant meteorological event, either Sandy or Katrina, and is located in a low-lying area impacted by tidal flooding and sea level rise.

When storms arrive, airports, cargo ports and financial centers close halting the movement of goods and people, slowing the economy and impacting people’s livelihoods. When land is washed away or homes and businesses are destroyed by floodwater, people’s life savings are threatened; they may be left homeless and jobless. These impacts will be more frequent as sea levels rise and storms become stronger.

What can we as ordinary citizens do to help prepare and protect our family, communities, and our society for sea level rise?

• Be educated. By learning all that we can about climate change and sea level rise, we can support efforts to stem the tide.
• Be prepared. Make sure our families are ready for a big storm by having a plan and the necessary items on hand to make sure we stay safe.
• Be inspired to take action. Support legislation that demands action on climate change and reduce your own carbon footprint. Having a home energy audit is a great place to start!

Join us for Boston Waters Rising on October 29th and learn more!

Today’s blog contributor is W2O board member Dianne Brown

Terms Defined

Storm Surge occurs when the winds from coastal storms push water inland. It occurs at all tide levels, but causes the most damage at high tides and king tides. In other words, the higher the water level at the time of the surge, the more water will be pushed inland, resulting in greater flooding. The greater the flooding, the longer it will last, simply because the water will take longer to drain away. The longer the flooding lasts the more human suffering and economic damage it will inflict.

A King Tide The height of a tide is controlled by the gravitational pull of the moon on the earth, which varies during the month, as the moon waxes and wanes. The tide is highest when we have a full moon or a new moon. A king tide occurs several times during the year when the moon’s elliptical orbit brings it closest to the Earth at the same time the Earth’s elliptical orbit brings it closest to the sun.

Sea Level Rise is an increase in the level of our oceans, relative to the land. It is generally measured in three ways: satellite data, tide gauges, and land benchmarks. Sea level rise is occurring because of two phenomena – the absorption of additional heat in our atmosphere by the ocean and the melting of land ice (glaciers & ice sheets). Although scientific estimates vary about the amount of sea level rise we will experience, due to uncertain rates of land ice melt, climate scientists all agree that globally seas have risen an average of 8 inches since 1880 and that they will continue to rise from their present level.