Driving into New York City, from the west, you must first endure miles and miles of salt marsh punctuated by industrial ruins.  You can see the factory here or there, the abandoned railroad beds, odd pieces of steel jutting from the water.  At night with a little fog on the water, it looks like a scene from the old Twilight Zone television show, not the western gateway to one of the world’s favorite cities.  The decaying infrastructure in the marsh also belies a set of assumptions and values.  The land for that old salt marsh never was worth much anyway.  Or was it? Researchers have studied the costs of various environmental regulations and how those costs are tabulated.  It turns out that regulations from the Clean Air Act tend to be viewed more favorably than Clean Water Act rules.  Part of the reason for this is that human health benefits comprise 95% of the economic benefits of clean air.  It is easy to quantify the health costs of lung-related diseases.  Water is a different story altogether.  The same researchers found that the economic benefits of clean lakes and rivers tend to be vastly under-estimated.  You can usually avoid a polluted lake or river, but you cannot avoid the air you breathe.    When calculating the economic value of something as exotic as marshes, rivers and lakes, both subjectivity and one’s values come into play.  How do we value the fact that marshes literally filter out toxic heavy metals and several other pollutants such as Bisphenol A (BPA) and perfluorooctanoic acid (PFOA used for non-stick cookware)?  The heavy metals can render groundwater and well water undrinkable while BPA and PFOA exert disruptive endocrine effects on wildlife and children.  Remove a marsh and release more harmful pollution to people and wildlife.  How much is that worth?   A recent algae bloom in Lake Erie was caused by fertilizer runoff from adjacent agricultural lands.  This, in turn, shut down a city of Toledo water processing plant until they installed $500M in upgrades.  Obviously, there was a quantifiable economic cost to the pollution in this case.   As a species, humans continue to be victims of our own hubris.  We think we know a lot more than we really do.  This causes one group to completely discount the benefits of clean lakes, rivers and marshes while another group will overstate the benefits.    Major pharmaceutical breakthroughs are often found in obscure plants and animals.  My nightmare scenario has a cure for cancer being found in a rare species only to have it rendered extinct by the construction of a parking lot.