Thinking about permaculture…
How Operation Catdrop saved the day
A story about the Law of Unintended Consequences.
IN the late-1950s the humble domestic cat and the British Air Force were about to come to the rescue of villagers in remote Borneo.
How did this strange alliance come about? How did a well-intentioned health intervention go awry? And just what was the relationship of the airborne cats and the Air Force?
The answer has to do with the seemingly arcane science of systems theory and to a law we should always watch out for in our design work with landscapes and people: the Law of Unintended Consequences.
A homely analogy
Before we look at the Borneo conundrum, let’s look at an incident that demonstrates not only the Law in action but the danger of making assumptions based on it.
Here’s how environmentalists saw it: Roguish permaculture practitioners were planting species which became outbreaks of weeds. Rampancy was rife.
Here’s how permaculturists saw it: We’ve heard all this before and it’s not true.
The environmentalists’ allegation was that permaculture practitioners were unintentionally engaging with the Law of Unintended Consequences by planting species that would spread to become weeds.
Permaculture practitioners alleged that the environmentalists were mistaking correlation for causation in saying their plantings were the cause of weed outbreaks.
Like so many stories repeated over time this one took on a life of its own, especially among people involved in environmental restoration activities like bushland regeneration. Like a politician repeating a dodgy story, this one was repeated so many time that people took it for fact. It became folklore in environmental restoration circles, however some in permaculture also became believers. To my knowledge, no firm evidence was produced to substantiate the myth. It remained a notion, a fear, that haunted restoration ecology circles.
Thankfully, the myth has since slid below the surface of the intellectual waters. Let’s hope it doesn’t propagate like a toxic algae to emerge again from those stygian depths.
Untrue it might have been, the myth does serve one purpose. It highlights the need to keep the Law of Unintended Consequences in mind when we design landscapes and social interventions.
To avoid the Law we ask an important question about elements in our design: what if? What if we do this (whatever this might be)? What could happen? Could it affect other elements in our design? Could it have impacts beyond the boundries of our project (like planting the allegedly weedy species)? Sure, this won’t reveal every potential consequence but it will give us a few to design contingencies around.
The parable of the swale
Let’s use another real-life story to look at this a little deeper. It is a story about excavating a swale, a trench excavated along the contour that retains and infiltrates overland flow into the soil to irrigate crops.
How could excavating a swale trigger unintended consequences? Would the swale perform differently if our soil is clay or sandy? Would it overflow during periods of prolonged rain? Could it cause erosion if it overflows? Would we have to excavate overflow channels to drain away excessive water? Would they become erosion rills? Would the flooded trenches of the swale pool water and create habitat for mosquito larvae?
Those unintended consequences happened in a permaculture project out on the far urban edge of Sydney some years back. The incident suggests that we have to plan for contingencies in our design. That is why the Law of Unintended Consequences really is a design consideration.
The strange tale of predatory cats
Now, a lesser-known example of the Law in action. The story unfolds like this…
Many of us know that mosquitoes are a vector for the spread of the debilitating disease, malaria, which affects so many people in the tropics. In the late 1950’s, the South East Asian nation of Borneo had a real problem with mossies. So it seemed fortunate that the World Health Organisation had a solution: spray DDT to kill the mosquitoes. The spraying included the inside walls and ceilings of the longhouses in which the tribal people lived.
This is where the Law of Unintended Consequences makes its appearance and triggers an unanticipated cascade of downstream impacts. It starts when DDT did what it was supposed to do — kill mosquitoes. Success. The incidence of malaria falls significantly. So far, so good.
What is not so good was how the DDT also killed the small wasp species that lived in the ceiling of the longhouses but didn’t kill the moth larvae. Why does that matter? Because for the larvae, the longhouse roof thatch is food. The result of this overlooked ecological fact starts to become apparent in the increasing rate of decay of the thatched roofs.
The cascade of ecological disruption does not stop with decaying longhouse roofs. When domestic cats come into the longhouses they pick up traces of the toxin and, licking their fur as cats do, they poison themselves. The cascade of collapse continues. Fewer cats, fewer predators. Fewer predators, and what happens? Mossie numbers might be down but not the numbers of rats whose population rapidly grows in the absence of their predator—cats. So too does the increasing incidence of the diseases rats spread… typhus and bubonic plague.
The well-intentioned measure to get rid of mosquitoes backfires into a cascade of unintended consequences. A bit of a dilemma, for sure. But what to do about it? The answer was simple. Replace the cats.
Now the challenge became one of finding a lot of cats. So where do you look for cats? In coastal villages, of course. A collection is started.
Cats caught, there is now another dilemma. How do you get all these replacement cats to isolated villages? It has become a problem not only of community health but of logistics. So who do you call when you have a logistical problem? The people who deal in solving logistical problems. The Air Force. Who else?
Being logistical thinkers, the solution to getting the cats into villages is obvious to the Air Force. Parachute them in. Now the problem is how to parachute dozens of cats safely to the ground. So why not build special containers? No lack of ingenuity here.
One of perhaps the most unusual air drops in military history gets underway. Cats from the air save the day. The rats are vanquished. Disease is staved off.
Is there anything to learn here?
The saga of the parachuting cats illustrates how a well-meaning public health intervention triggered a cascade of connected impacts involving both wild and domestic animals that could not then be foreseen.
It was largely unpredictable because in the fifties ecology was not all-that-well known a science, and nor was the systems thinking that would have made clear the possibilities inherent in the Law of Unintended Consequences.
Despite this, people put one-and-one together, made the connections and came up with an innovative solution that became the Saga of the Parachuting Cats. It worked, which goes to show that, as Einstein said, imagination is more important than knowledge.
More reading for idle moments…
