Tuesday, June 26, 2012

Oh My! Sea Level's Rising and We're All Gonna Die!

Somebody sent out a press release today saying that sea level on the East Coast of the United States is rising faster than elsewhere (where else?  I dunno), and that we can expect all the problems that they've been screaming screeding about for the fast few years.  It was in three sites this morning, and I expect more tomorrow:

Here's the Baltimore Sun version:Study finds sea level rise accelerating along Atlantic coast
Sea levels are rising faster along the Atlantic coast - including in the Chesapeake Bay - than elsewhere around the world, and the increase appears to be accelerating, according to federal scientists.

In a paper published online in Nature Climate Change, the U.S. Geological Survey reports that sea level rise is increasing three to four times faster than globally along a heavily-populated 600-mile stretch of coast from Cape Hatteras, NC to north of Boston.

Since 1990, the rise has increased 2 to 3.7 millimeters per year in the "hotspot," as the federal scientists call it, compared with a global increase of 0.6 to 1 millimeter per year. That hotspot includes the Chesapeake Bay, according to USGS oceanographer Asbury H. Sallenger, lead author of the report.

"If you raise sea level across the mouth of the Chesapeake Bay, it's going to increase the overall level of the Chesapeake Bay," he said.

Climate change causes sea level to rise as land-based ice near the earth's poles melts, but also as rising temperatures cause the ocean water to expand. But researchers expect sea-level rise to vary around the globe because of various factors, including ocean currents, differences in sea-water temperature and saltiness and the earth's rotation.

The trio of USGS scientists found that tide gauge data over the past 60 years tend to confirm computer models that have forecast an increase in sea level rise along the Atlantic. The models have hypothesized that ocean currents running along the Atlantic coast are slowing, resulting in increases in sea level, Sallenger said....
 Similar articles at CBS Baltimore and Boston's NPR site.

So now, lets look at some data.  How about Baltimore:

See any important (I won't use the word significant because it has important statistical meaning) increase in the rate of sea level rise?  Nope, me neither.  I see lots of short term variation, and some decadal scale wiggle, but overall, sea level in Baltimore has been rising at a pretty constant rate since about 1910. 

Lets look farther south, Charleston South Carolina:

Look, almost exactly the same patterns, and the same rate, within the error on the slope.

OK, lets look farther north, The Battery, New York

An even longer record,  still linear, and with a slightly lower slope (the land is rising instead of sinking).

So what increase in the rise of the sea level rate are they talking about?  Well, if you take the midpoints of 50 year intervals and plot them every ten years, you get something like this:
In this graph we see the that the rate of sea level rise in Baltimore has shown a sinusoidal variation with higher rates in the 1920s-1950s, and then lower rates from 1950-1990.  In the early part of the 20th century the rates were higher than in the latter, and after a minimum around 1970, are starting to return to the rates of the 1940s and 1950s!  Oh my God, we're all gonna drown, just like we did in the 1950s!

Not to mention the silliness of the assumption the sea levels rises can be concentrated in a region over the long run.  At 1 mm extra accumulation a year, in 10,000 years, the water over the East Coast would form a hill about 30 feet high.  I guess that plumber who taught me shit don't flow up hill didn't know his shit.

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