Don't just do something, stand there! Reflections on the counterintuitive behavior of complex systems, seen through the eyes of System Dynamics, Systems Thinking and simulation.
Very big hail on Wednesday … I managed to duck into a gas station, so my car only got 2 dents and a windshield crack; others weren’t so lucky. These are the little ones:
Big ones took out windows at the law office I was visiting. The hospital treated 10 people for injuries.
No? So why do we let lawyers design control systems for our economic and social systems, without much input from people trained in dynamic systems?
Balaton Group colleagues Jørgen Nørgård, John Peet & Kristín Vala Ragnarsdóttir have a nice history of The Limits to Growth in Solutions.
The device designed to cut the oil flow after BP’s oil rig exploded was faulty, the head of a congressional committee said on Wednesday … the rig’s underwater blowout preventer had a leak in its hydraulic system and the device was not powerful enough to cut through joints to seal the drill pipe. …
Markey joked about BP’s proposal to stuff the blowout preventer with golf balls, oil tires “and other junk” to block the spewing oil.
“When we heard the best minds were on the case, we expected MIT, not the PGA,” said Markey, referring to the professional golfing group. “We already have one hole in the ground and now their solution is to shoot a hole in one?”
The BBC today carries the headline, “US manufacturing output hits 6 year high.” That sounded like an April Fool’s joke. Sure enough, FRED shows manufacturing output 15% below its 2007 peak at the end of last year, a gap that would be almost impossible to make up in a quarter. The problem is that the ISM-PMI index reported by the BBC is a measure of growth, not absolute level. The BBC has confused the stock (output) with the flow (output growth). In reality, things are improving, but there’s still quite a bit of ground to cover to recover the peak.
I went out in the woods yesterday to find tracks of the coyote who kept me up all night by howling outside my window. I found them, but more interesting was this:
Enter hapless bunny, stage left. He hops along for a bit, then a hawk swoops down and gobbles him up. Notice the wingtip print at right, and lack of further bunny prints.
A critique of Lindzen & Choi’s 2009 paper has just been published, debunking the notion of strong negative temperature feedback in the tropics. I had noticed that its statistical method of identifying intervals in a time series was flawed, and that models cited appeared to sometimes lack volcanic forcings, rendering correlations meaningless. I’m happy to see those observations confirmed, and a few other problems raised. (I’m happy that I was right, not that climate sensitivity is higher than Lindzen & Choi suggest, which would be good for the planet.) I haven’t read the details of the critiques, so I can’t say whether this really closes the book on the question, but it at least indicates that the original work was a bit sloppy. Since Lindzen is one of the few contrarians who knows what he’s doing, and it’s useful to have such people around, I wish he would focus less on WSJ editorials and more on scholarship.
Check out my guest post at Inside-Out China.