According to a new report just released by the National Oceanographic and Atmospheric Administration (NOAA), average sea level around the world is projected to rise anywhere from 8 inches to over 6 feet by 2100.  That seems like a large range, so what does that mean?  NOAA developed the sea level rise range based on four scenarios, that include varying amounts of ice sheet loss  in Greenland and West Antarctica and different levels of ocean thermal expansion (warming of the ocean waters).  From 1900 to 2000, the average global sea level rose 8 inches, so it seems safe to say that another rise of 8 inches would be the absolute minimum we could expect by 2100.  At the high end, a rise of over 6 feet would occur if global ice sheets melted at the worst-case rate between now and 2100.  However, the rate at which glaciers and ice sheets will melt is the greatest source of uncertainty in sea level rise projections. No one has the answer for this difficult scientific question, as there is a lot more that goes on with ice dynamics than meets the eye.

So what does all this mean for South Florida?  Regional projections in sea level rise are a tough, but necessary business. While we can try and hope for the best, officials need to plan for large changes in sea level. (Better safe than sorry, right?)  South Florida is particularly vulnerable, with a large population along the east coast and the unique and fragile Everglades to the west. Not to mention the fact that Florida sits on top a limestone bed, which is very porous and allows for rising seawater to intrude into our freshwater drinking supply. Also, even a small increase in sea level can lead to a greater chance for urban flooding events, especially during storms (think Hurricane Sandy).  We all know that South Beach already floods during an afternoon thunderstorm, so this could very well become a more frequent occurrence throughout South Florida.  And depending on the extent of sea level rise, some places could disappear altogether. In the images below, you can see what Florida will look like (and which areas will be underwater) if the sea level rises to a given level. If you want to experiment with what U.S. coastlines will look like as the sea level rises, go to NOAA’s Sea Level Rise and Coast Flooding Impact Viewer.

To learn more about sea level rise and storm surge threats, come visit our two exhibits Water, Wind and Waves: Miami in a Changing Climate, funded by NOAA, and Hurricanes, funded by the FIU’s International Hurricane Research Center.

The Miami coastline, with a 1 foot increase in sea levels. Shades of blue indicate areas underwater; green indicates low-lying areas.

The Miami coastline, with a 3 foot increase in sea levels. Shades of blue indicate areas underwater; green indicates low-lying areas.

The Miami coastline, with a 6 foot increase in sea levels. Shades of blue indicate areas underwater; green indicates low-lying areas.

]]> http://www.miamisci.org/blog/put-on-your-rain-boots-the-water-is-rising/feed/ 0 http://www.miamisci.org/blog/what-is-sclerochronology/ http://www.miamisci.org/blog/what-is-sclerochronology/#comments Mon, 11 Jul 2011 09:38:19 +0000 admin http://www.miamisci.org/blog/?p=311 Continue reading →]]>

Most everyone was told growing up about how when a tree is cut down, you can look at the tree rings to figure out the tree’s age, and also how much the tree grew each year. Dendrochronology deals with this type of science, which can help us understand environmental conditions in the past – and even tell us whether a Viking ship was built in the year 819 or 820. Dr. Kevin Helmle, who is a research scientist at the University of Miami’s Rosenstiel School of Marine and Atmospheric Science (RSMAS) and NOAA’s Atlantic Oceanographic and Meteorological Laboratory (AOML), talked to students participating in the Digital WAVE program about another way to “tell time.” He works in sclerochronology, which means using layers in coral cores, in a similar way as rings in tree trunks. Annual layers of coral growth can be studied to provide information on environmental and climate history over many past centuries. Dr. Helmle brought real coral cores to show, and also showed students x-ray images of interior coral layers (see image below). By looking at the size and density of the layers, scientists like Dr. Helmle can determine things like the water temperature, water chemistry, and exposure to light the coral experienced at that time. Students then looked at the coral x-ray images, identified layers that corresponded to important years in their lives (or in history), and looked at real data for that year to find out what was going on in the oceans at that time. Just like real sclerochronologists!

X-radiographic positive print (left) with annual density bands (dark bands = high density, and light bands = low density) and a photograph of the coral slab (right). Helmle, K. P., and R. E. Dodge (2011), Sclerochronology, in Encyclopedia of Modern Coral Reefs; Structure, Form and Process, edited by D. Hopley, pp. 958-966, Springer Verlag. Doi:10.1007/978-90-481-2639-2_22