How Much Will The Water Rise?


Combining data from the 2010 Census and the US Geological Survey, Stephen Von Worley explains his mapping of the vulnerability of 10 major coastal cities in the US:

Above, we see [Boston], with dense residential neighborhoods colored by elevation: white at the mean tide line, fading to yellow at 12 feet, orange at 25 feet, and blue at 50 feet or more above sea level, with less-populated areas represented by the same scheme, darkened proportionally.

A recent report warned the Pentagon about the security threat of rising sea levels, which currently threaten more than 30 US military bases. Meanwhile, scientists at the University of Innsbruck calculate that, between 1902 and 2009, glacier melt added around 8.6 inches to sea levels. From a forecast for the current century:

Melting glaciers will raise the sea level between [6 and 8.6 inches] until 2100. "Where we end up within this range is up to us – it mostly depends on how much greenhouse gas we will emit", says [Dr. Ben Marzeion from the Institute for Meteorology and Geophysics]. The same is true for the longer term: "Until 2300, we can expect the sea level to rise between [9.8 and 16.5 inches] due to glacier melt. With [16.5 inches of] sea level rise, most of the glaciers of the world will be gone, leaving behind only small remains in very high altitudes."

Climate change skeptics tend to counter these assessments with the observation that sea levels have stabilized – or even dropped – over the last few years, despite steadily climbing CO2 levels. However, Open Mind parses new research on the El Niño–Southern Oscillation weather pattern, which, since 2010, has transferred water mass from oceans to land via precipitation, primarily in Australia, South America and Asia:

This new understanding of the 2010/2011 sea level drop, one of the more notable short-term fluctuations in sea level, raises hope that we may finally be getting a handle, not only on the slower changes due to global warming, but the faster changes due to fluctuation effects like [the El Niño–Southern Oscillation]…. It also shows the folly of hopes that the 2010/2011 sea level drop should allay fears of continued global-warming induced sea level rise.

Recent Dish coverage on rising sea levels here and here.