Disappearing Mississippi Delta, 1972 - 2014

Like many folks, we were astonished by the recent ProPublica / The Lens mapping work showing the tremendous loss of marshland in the Mississippi Delta and adjacent parts of the Gulf coast.  There is an unholy alliance of factors responsible:  the rise in sea level due to melting onshore glaciers and icepack, and thermal expansion of the ocean, two consequences of global warming; the natural, inexorable subsidence of the Delta as that huge pile of sediment compresses and sinks under it's own awesome weight, actually depressing the Earth's crust; the diversion of Mississippi River sediments away from the marshes and out into the Gulf, thanks to an impressive system of dams, levees, and pumps designed to control flooding and aid navigation; and the accelerated erosion of marshlands thanks to the criss-crossing network of ditches and canals dug willy-nilly by the oil and gas industry over many decades -- the death by 1,000 cuts.  

This last factor has prompted some of Louisiana's coastal parishes to sue the oil and gas industry, a "bite the hand that feeds you" course of action that might have been unthinkable just a few years ago.  But desperate times breed desperate measures.  There is an ambitious $50 billion plan to "fix" the Delta.  The billions of dollars in Clean Water Act fines that BP and their partners will pay for the 2010 BP / Deepwater Horizon oil and gas disaster could provide a solid downpayment on this recovery plan.

Here's our own look at the severity of the problem.  Thanks to the colossal archive of Landsat satellite imagery available for free via the US Geological Survey, we can time-travel back to the early 1970s to get a big-picture perspective on how much has changed.  Click on the images to see a larger version:  

1972: Mississippi Delta and Louisiana coastline as seen on August 7, 1972, just 15 days after the launch of the first Landsat Earth-imaging satellite.

2014: This mosaic of two images collected by the Landsat-8 satellite in 2014 starkly illustrates the loss of marsh vegetation (green)  over the past four decades.