I’ve been studying global climate change a lot lately. I just can’t make up my mind. It’s basically a fight between my rational/logical brain, and my intuition.
My rational, logical mind understands the basic physics behind the theory that all the Carbon Dioxide we’ve put into the air has altered (and will continue to alter) the climate. The theory has been around a long time and has been experimentally verified. There are a lot of really smart people who think the earth is getting warmer due to human activity. They couldn’t all be wrong, could they?
My intuitive mind, on the other hand, has a hard time believing that climatologists have gotten it all correct. I have a lot of questions about their methodologies and the results they have found. I figured the best way to answer these questions would be to talk to a climatologist, so that’s what I decided to do. I’ve emailed several climatologists with questions I had about global climate change. I’ll post the answers when I get them back. Stay tuned!
Here are the questions I asked:
- From what I’ve read, there are a bunch of weather stations around the world, and the temperature measurements from these weather stations are mathematically combined to form the global average temperature. How can climate scientists be sure that the mathematics they are using to combine the temperature measurements together are correct? A theory which proposes an experiment can easily be validated – you simply perform the experiment and see if the theory holds up. How do you validate something that is purely a measurement, and makes no direct predictions?
- I have a similar question about paleo-climatology. I don’t see how ice core measurements, tree ring data, and other proxies for temperature that are used before the mid 1800’s could give any degree of accuracy. Wouldn’t you need to measure tree rings all around the world and then combine them together, again using some complicated math? Are there statistical confidence intervals for the accuracies of historical climate reconstructions? Where can i find those?
- The changes in the earth’s average temperature are measured to be on the order of 1 degree Celsius over 100 years. That doesn’t seem like much to me. The only explanation that I have come up with for the reason that such a small change puts us in danger is if the climate system is a chaotic system. Is our climate a chaotic system? If so, my understanding of chaotic systems is limited but it seems unlikely to me that a computer simulation could ever have much hope of predicting much about a chaotic system, because you’d never have an accurate understanding of the initial conditions, and even slight errors in the initial conditions would cause the climate’s actual behavior to diverge wildly from what our models predict [see question 5]. If the climate system is not chaotic, then how does such a small change in temperature cause so much damage?
- Mathematically, the temperature of the earth has to exist, but it seems to me that it would change so fast and fluctuate so much that talking about changes of fractions of a degree doesn’t make much sense. My understanding of atmospheric models is that they usually treat the atmosphere as having different layers, each with different thermodynamical properties. If the average surface temperature increases, but this increase is offset by a decrease in the average temperature of one layer of the atmosphere, I should think the climate would definitely change even though the ‘average global temperature’ would remain unchanged. Is it ever useful to talk about a “global average temperature”? Can we get a more complete picture by looking at the temperature distribution function over time? I’m curious to know what that function would look like, but I have been unable to find it.
- The best thing about science (in my humble opinion) is that it’s usually pretty easy to tell who’s right; if a theory is repeatedly verified experimentally then there’s a good bet that the theory is accurate. It’s my understanding that the theory of Carbon Dioxide trapping some radiation into space and thereby increasing the temperature of the stratosphere has been repeatedly experimentally verified. I’m very curious, however, about the historical accuracy of climate models. So far, all I have been able to find is a comparison of James Hansen’s 1988 predictions of the change in temperature anomaly and the actual observations made up to 2006. It looks like the models accurately predicted the real change in temperature, but in his paper “Global Temperature Change,” Hansen says that “Close agreement of observed temperature change with simulations for the most realistic climate forcing is accidental, given the large unforced variability in both model and real world.” Maybe I’m misreading him, but it sounds like he’s saying ‘the models were right, but that was a fluke.’ How statistically accurate were climate models from the 90’s in predicting the climate variability we experienced over the past decade?
- I have heard many different predictions about the effects of anthropogenic global warming, ranging from incredibly bad (the demise of many species, potentially including the human race) to mildly good (improved crop yields in the northern hemisphere, fewer deaths due to extreme cold.) How much danger do you believe global warming poses for the human race? Is it true that some countries might actually benefit from global warming?
- I read that even if we stopped all CO2 emissions immediately, the earth’s temperature would still rise at the same rate (~1 Degree Celcius / Century) for some time, because it would take a long time to remove those gases from our atmosphere. Some people have proposed geoengineering as the solution to the problem of global warming, arguing that cutting emissions would be “too little, too late.” Do you think any geoengineering approaches are a viable solution to the problem?
![[Happiness on a Typical Day]](http://markpneyer.com/images/happiness_graph/HappinessGraph_SampleDay.png)




