... gang aft agley

When I taught environmental science, I frequently ran into what I call the "Why Don't We Just...?" mentality.

Presented with an ecological problem -- say, plastic pollution in the ocean -- someone would inevitably propose something that drastically oversimplified the issue.  "Why don't we just equip ships with giant nets to scoop it all up?"  The problems with this include:

• There is way too much plastic trash in the ocean to feasibly remove by ships with nets.
• A lot of the problem isn't the big stuff, but the microplastics -- fragmentary pieces of plastic debris -- that get into the food chain, clog up the feeding apparatus of filter-feeding animals, cloud the water, and may be directly toxic.  These microplastics would almost certainly slip right through.
• Any scoop operation would inevitably catch and kill marine organisms that got caught up in the nets.
• Even if it was possible, what would we do with the trash once it was scooped up?

It brings to mind the quote by H. L. Mencken: "For every complex problem, there is a solution that is clear, simple, and wrong."

The difficulty is, the global ecosystem is an intricate web of relationships that connect to each other in sometimes unexpected ways, meaning that perturbing the balance is easy and fixing it once you've perturbed it is not.  Take, for example, the attempt to eradicate rats from Palmyra Atoll, which was the subject of a paper in Biotropica last month.

The problem seemed simple enough.  Black rats were accidentally introduced to Palmyra during World War II, and as they have done in so many places, they more or less proceeded to take over.  The low-lying island proved to be a smorgasbord for the invasive rodents, with seabird eggs and young and the seeds and fruits of native trees to feast upon.  The result was predictable enough: seabird populations dropped precipitously, and native plant species were in trouble as well, because the rats ate the seeds so voraciously that there were literally no new saplings to replace any that died.

So, what to do?  To save the ecosystem, a trio of agencies overseeing the island -- the U.S. Fish and Wildlife Service, The Nature Conservancy, and Island Conservation -- got the funding for a massive rat eradication program.  It was successful, and amazingly enough, the last rats on Palmyra were killed in 2011.

All better, right?  Pristine wilderness resurgent?

Not exactly.

[Image is in the Public Domain]

Let's start with the good stuff first.  The Asian tiger mosquito, another exotic import, didn't last too long after the rats were gone.  They're specialists in feeding on mammal blood, and the rats were all there was, so the bloodsucking little fiends all starved to death.  (I love wildlife as much as the next tree-hugger, but I have to say that in the case of the tiger mosquito, good riddance.)  The seabirds bounced back pretty well, with no predators eating the young.

The forests, however, were a different story.

It turned out the rats were not only eating native seeds and fruit, they were keeping down the population of another exotic -- the coconut palm.  With a flourishing rat population, only a very small percent of the coconuts produced made it to the ground without being gnawed to pieces.  Now that the rats are gone, the palms are going nuts (*ba-dum-bum-kssh*) and outcompeting just about every other kind of vegetation on the island.

"I was on the island in 2012, just after the eradication, and could easily navigate through the open jungle understory," said study lead author Anna Miller-ter Kuile, of the University of California - Santa Barbara, in an interview with Science Daily.  "Two years later when I went back, I was wading through an infuriating carpet of seedlings that were taller than me, tripping over piles of coconuts...  While there was a fourteen-fold increase in seedling biomass, most of these new seedlings were juvenile coconut palms, their proliferation left unchecked by the removal of the rats."

As Robert Burns put it, "The best laid plans of mice and men gang aft agley."

It brings to mind the Precautionary Principle: it's always easier and cheaper to prevent a problem than it is to fix it afterward.  The classic example of this is the mess down in south Florida created by the straightening of the Kissimmee River, which used to be a slow, meandering stream snaking its way through the Everglades.  Mostly motivated by draining swampland for agriculture and suburban expansion, the Army Corps of Engineers launched a project in the 1940s to change the river's course, reducing its fifty-kilometer pathway by about half.

They succeeded.  In the process, they destroyed wetlands that had been pristine wildlife habitats, reducing bird populations in some places by 90%.  The deepening of the channel caused a faster water flow, draining so much water from the surrounding land that sinkholes started opening up, some of them actually swallowing up houses.  Silt runoff into the Gulf of Mexico caked coral reefs and wiped out shallow-water marine ecosystems, including the ones supporting lucrative fisheries.

So in the 1970s, the Army Corps of Engineers kind of went, "Oops," and launched the Kissimmee River Restoration Project.  The current cost to return the area to where it was prior to trying to improve things: $578 million.  And that's not even considering how feasible it is to actually fix it.  As the study on Palmyra Atoll shows, it's not easy to repair a damaged ecosystem even if you try.  The "Why Don't We Just...?" mentality is almost always tempting, and almost always wrong.

It seems fitting to end all this with a quote from John Muir, the American environmentalist who founded the Sierra Club: "When you try to pick out one thing by itself, you find it hitched to everything else in the universe."

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This week's Skeptophilia book recommendation of the week is about one of the deepest mysteries in science: the origin of time.

Most physical processes are time-reversible.  If you looked at a video of a ball bouncing off a wall, then looked at the same video clip in reverse, it would be really difficult to tell which was the forward one and which the backwards one.  Down to the subatomic level, physical processes tend to make no distinction based upon the "arrow of time."

And yet our experience of time is very, very different.  We remember the past and don't know anything about the future.  Cause and effect proceed in that order, always.  Time only flows one direction, and most reputable physicists believe that real time travel is fundamentally impossible.  You can alter the rate at which time flows -- differences in duration in different reference frames are a hallmark of the theory of relativity -- but its direction seems to be unchanging and eternal.

Why?  This doesn't arise naturally from any known theory.  Truly, it is still a mystery, although today we're finally beginning to pry open the door a little, and peek at what is going on in this oddest of physical processes.

In The Order of Time, by physicist Carlo Rovelli (author of the wonderful Seven Brief Lectures in Physics), we learn what's at the cutting edge of theory and research into this unexplained, but everyday and ubiquitous, experience.  It is a fascinating read -- well worth the time it will take you to ponder the questions it raises.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

Listening to Cassandra

I like to think of myself as basically an optimistic person, and someone who looks for the best in my fellow humans.  But there are times that I think that a gigantic meteor strike might, all things considered, be the best option at this point.

Those times usually occur when people persist in a behavior that is known, for absolute certain, to be self-destructive.  And surprisingly enough, I'm not talking about climate change here, and our determination to keep burning fossil fuels despite the near-universal consensus amongst climatologists that this practice is drastically altering the Earth's climate.  What I'm referring to is two stories that both broke day before yesterday, and that leave me shaking my head and feeling like whatever happens to our species, we kind of deserve it.

The first, and more local, example of this phenomenon was described in an article in NPR Online, the title of which sums up the problem succinctly: "Levees Make Mississippi River Floods Worse, But We Keep Building Them."  The article, written by Rebecca Hersher, describes the ongoing catastrophe along the Mississippi River, wherein every single year there are destructive, often deadly, floods.

Here's a capsule summary of the problem.

Before the 20th century, the Mississippi had a habit shared by many large rivers; overflowing its banks during the rainy season.  This phenomenon had a couple of effects.  First, it brought the silt picked up along the way out of the river basin, depositing it on land.  Second, it meant that regular, minor floods -- the sort of thing one can prepare for and cope with -- were kind of a way of life.  (Why, for example, my uncle's fishing cabin in Henderson, Louisiana was built on stilts.)

But when the population started both to grow and urbanize, these floods were "mitigated" -- by installing a system of levees and spillways to "tame the river."  Mostly constructed in the 1930s and 1940s by the Army Corps of Engineers, the (well-meant) attempt to stop people from being flooded out every year had two unexpected effects.

One is that the silt that would have been deposited to either side of the river now was kept in the river itself.  This left only two places it could go -- deposited onto the river bottom, or flushed out into the Gulf at the delta.  The first raised the riverbed, and the second raised the mouth of the river; both of these had the effect of pushing the level of the river upwards.  Simultaneously, the silt that was in the river didn't end up on land, and the land itself started to subside.

Rising river + sinking land = a need for bigger levees.  So the levees were raised, making the problem worse -- and so on and so forth.  I still vividly remember being in New Orleans and walking along a footpath at the base of a levee along the Mississippi -- and looking up to see the top of a shrimp boat going past, about thirty feet above my head.

The 17th Street Canal in Metairie, Louisiana [Image licensed under the Creative Commons No machine-readable author provided. Infrogmation assumed (based on copyright claims)., MetOutletCanalDogwalkerBreechBkgrd, CC BY 2.5]

The second unexpected effect follows directly from the first.  If you build higher levees, the water level rises, so when the levees break, you don't have a minor flood, you have a catastrophic one.  This, of course, is what happened in New Orleans in 2005 during Hurricane Katrina, but it's inevitable that it'll happen again in the near future.

The kicker?  We've known about this problem for ages.  In 1989 John McPhee wrote an incredible book on the topic, called The Control of Nature, in which he laid out the problem clearly.  And what have we done differently since then?

Nada.  Build more levees.  Pretend we know what we're doing, and that nature won't ultimately have the last word.

The other example of humans doing idiotic self-destructive stuff revolves around something I always mention in my biology classes as the time our species did something right; the 1989 Montreal Protocol that banned the production or use of chlorofluorocarbons, a class of chemicals used as coolants and propellants that were thought to be harmless but turned out to destroy the atmosphere's protective ozone layer.  Almost all the nations on Earth signed on -- surely one of the only times in humanity's history where damn near everyone has agreed on something.

Or so we thought.  Since 2012, there's been a sudden and mysterious uptick in the amount of CFCs in the atmosphere -- up, at one estimate, by 25%.  As of the time of this writing, no one's quite sure where it's coming from.  Up until now, the CFC levels have been gradually falling (and ozone hole gradually diminishing) as the CFCs from before 1989 have broken down -- but it appears that we're not done with this problem yet.

"It is not clear why any country would want to start to produce, and inadvertently release, CFC-11, when cost-effective substitutes have been available for a long while," said NASA scientist Robert Watson, who led the studies thirty years ago that led to CFCs being banned.  "It is therefore imperative that this finding be discussed at the next Ministerial meeting of Governments given recovery of the ozone layer is dependent on all countries complying with the Montreal Protocol (and its adjustments and amendments) with emissions globally dropping to zero."

Durwood Zaelke, founder of the Institute for Governance and Sustainable Development and an expert on the Montreal Protocol, was more unequivocal still.  "Somebody's cheating.  There’s some slight possibility there’s an unintentional release, but… they make it clear there’s strong evidence this is actually being produced...  This treaty cannot afford not to follow its tradition and keep its compliance record...  They’re going to find the culprits.  This insults everybody who’s worked on this for the last 30 years.  That’s a tough group of people."

So at least we have some folks who are on the case.  What kind of power to compel they will turn out to have, once the culprits are identified, remains to be seen.  And here in the United States, we've seen in the past year a weakening of damn near every environmental regulation we have, in favor of corporate profit and short-term expediency.  So how much help our government will be is questionable.

I'm holding out some hope that at least by publicizing these issues, people are beginning to wise up.  However, our inaction on climate change -- a phenomenon we've known about since the 1890s -- doesn't bode well.  Mostly what has happened is that the people who are brave enough to sound the warning have turned into Cassandras -- prophets who are cursed to be correct, but no one believes them.

As for me, I'm trying to maintain my optimism, but after reading these two articles, right now mostly what I'm doing is scanning the skies looking for the incoming meteor.

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This week's book recommendation is a brilliant overview of cognitive biases and logical fallacies, Rolf Dobelli's The Art of Thinking Clearly.  If you're interested in critical thinking, it's a must-read; and even folks well-versed in the ins and outs of skepticism will learn something from Dobelli's crystal-clear prose.