Tomorrow is Earth Day, so I thought I'd write a few thoughts about that. But first, some seemingly-unrelated anecdotes. Bear with me; I'll get to my point at the end.
The movie Airplane! starts with a scene outside of LAX. A man flags down a taxi, and hops in. The taxi driver says, "I'll be right back," starts the meter running, and goes inside the airport. After chasing down his ex-girlfriend and having a long heart-to-heart talk, the taxi driver buys a one-way ticket to Chicago. At this point, the camera cuts back to the passenger in the taxi, who is still waiting patiently. At the end of the movie, after the plane flies to Chicago (at least 4 hours!), the camera cuts back to the guy in the taxi, where the meter now reads $113. The passenger says, "Well, I'll give him 20 more minutes, but that's it!"
A few weeks ago, I took my car in for an oil change. During the servicing, the mechanic told me that the battery was bad and needed replacing. Now, I'm normally very skeptical of what mechanics tell me during an oil change, and I get second opinions before getting any expensive servicing done. But I'd noticed that, on cold mornings, the engine would struggle to get started, and I'd noticed a few other electrical issues when the engine was off. Since my existing battery was still under warranty, I took it back to Sears for further testing. Sure enough, it was bad and needed to be replaced.
Now I could have waited until the battery completely failed to be certain that there was a problem, and not relied on mechanics who want me to spend my money there at the shop. However, Murphy's Law dictates that the battery would not have failed me on a Saturday morning when I just happened to be parked in the mechanic's driveway. No, it would more likely have failed on a drive through west Texas, where I'd have to pay for a 100 mile tow to the nearest shop and buy a battery at 3 times the price. So, instead of taking that risk of a much more expensive repair, I had the battery replaced at Sears, where the warranty covered half the cost of a new battery.
Another story: I grew up in rural Pennsylvania, where our house was supplied with water from a well. Due to the geology of the area, our well water was quite acidic (pH of 4, roughly that of soda pop). In the 6 years before I went to college, we had the bottom rust out of two hot water heaters. A plumber told us that this was due to the acidity, and suggested that we install a neutralizer and water softening system. This was very expensive, and the yearly maintenance on the system was expensive enough that it was cheaper to buy water heaters every few years. But we had other signs that not all was well with the plumbing. All of our sinks and tubs were stained green with copper that was being leached out of the pipes by the acidic water. Our chrome faucets tended to drip, and where the drips formed, the chrome had been eaten away. In short, it was just a matter of time (maybe a decade, maybe just few years) before the entire plumbing in the house would need to be replaced. But the plumbing had last for 30 years, and new plumbing would last at least as long, so the average yearly dollar cost may still have been less than the yearly cost of the neutralizing system. But my parents decided that the hassle of replacing the plumbing and the potential loss of our belongings in a flooded basement were not worth a lower average cost, and they payed through the nose to get the expensive water neutralizer and softening system. It cost a lot, and it was unclear how long we would have to wait to recoup the cost (if ever), but it saved us the huge mess of having to replace pipes, valves, faucets, and water heaters. (It turned out that some of these had to be replaced anyway, because we'd waited a little too long to buy the neutralizer, but we did avoid re-plumbing the entire house.)
What do these stories have in common? Each featured a person who had to make a decision on the cost of waiting before acting. The guy in the taxi was pretty stupid, as it wouldn't have cost him anything to flag down a different taxi, plus he wouldn't have to wait hours to get home. Fixing the battery in my car was pretty much a no-brainer, because the signs that the battery was failing were there, the cost of the repair was pretty cheap, and it undoubtedly saved my a big expense and hassle at some point down the road. The plumbing repair in my parents' house was a tougher call. In retrospect, it was obviously the right move, but at the time, it was a huge expense. The signs all pointed to that repair being the right thing to prevent a big plumbing disaster, but a lot of the cost-benefit analysis results were unclear if the only consideration were dollar costs.
As humans, we've reached a point of decision in regard to global warming. We can decide to do nothing, hoping that nothing will happen. That's like sitting in the taxi and hoping the driver will come back, when the driver's really on an ill-fated flight to Chicago.
We can also look at the huge costs of revamping our infrastructure to combat global warming. It's a big expense in the short term. Some people claim that the long-term costs of ameliorating global warming (e.g., higher energy costs for air-conditioning, costs of relocating agriculture from existing areas that will become to dry, costs of piping water to newly-arid locations, costs of wars and human resettlement due to climate change, etc.) will be less than the costs of trying to reverse global warming. In pure dollar amounts, maybe this is so, though I doubt it (I'd be willing to be my career that the cost of inaction will be many times the cost of present action.) When you add in the cost in human life and hassle to human beings, it's not worth it, in my book. It seems more prudent to bite the bullet and take the preventative measures before we have a huge(r) mess on our hands.
The signs that man-made global warming is real and is a threat are all around us. We can ignore it and hope that we are misinterpreting the signs, and we risk a flood of disasters or being left in the wilderness with no way out. Or, we can take steps now that, while costly and not able to prevent all problems, will prevent the worst-case scenarios. I vote for the prudent path.
So, do we wait and hope, or do we act?
Tomorrow, I'll shoot down some of the astronomy-related myths that global warming deniers spout out when they try to convince people to wait another 20 minutes, just in case the driver comes back.