Systems thinking: A cautionary tale

Operation Cats Drop: Script

In the 1950s, the Dayak people of Borneo, an island in Southeast Asia, were suffering from an outbreak of malaria, so they called the World Health Organization for help. The World Health Organization had a ready-made solution, which was to spray copious amounts of DDT around the island. With the application of DDT, the mosquitoes that carried the malaria were knocked down, and so was the malaria.

There were some interesting side effects, though. The first was that the roofs of people’s houses began to collapse on their heads (sound 50-52). It seems the DDT not only killed off the malaria-carrying mosquitoes, but it also killed a species of parasitic wasp that up to that point had controlled a population of thatch-eating caterpillars. Without the wasps, the caterpillars multiplied and flourished, and began munching their way through the villagers’ roofs.

That was just the beginning. The DDT affected a lot of the island’s other insects, which were eaten by the resident population of small lizards called geckos. The biological half-life of DDT is around 8 years, so animals like geckos do not metabolize it very fast, and it stays in their system for a long time. Over time, the geckos began to accumulate pretty high loads of DDT, and while they tolerated the DDT fairly well, the island’s resident cats, which dined on the geckos, did not. The cats ate the geckos and the DDT contained in the geckos killed the cats. With the cats gone, the island’s population of rats came out to play and we all know what happens when rats multiply and flourish. Pretty soon the Dayak people were back on the phone to the World Health Organization, only this time it wasn’t malaria they were complaining about. It was plague and the destruction of their grain stores caused by the overpopulation of rats. This time, though, the World Health Organization didn’t have a ready-made solution and had to invent one: they decided to parachute live cats into Borneo. “Operation Cat Drop” occurred courtesy of the Royal Air Force and eventually stabilized the situation.

Morale of the story:

• If you don’t understand the inter-relatedness of things, solutions often cause more problems
• Simple questions often require complex and reflective thinking if good solutions are to be found
• It is always better to manage by design than by default