drugs and global warming

Today I think I learned that it's such common knowledge that tobacco causes 40% of illness-related hospitalizations and alcohol causes half of emergency room visits that you don't have to cite your sources. I could have tried looking those up, but I also learned that a bunch of sixth-graders in Longmont, CO held a debate and concluded that global warming isn't caused by humans. They used data found on the internet on Wednesday, I assume during class, and they didn't see An Inconvenient Truth. Since I have 45 minutes, an internet connection, and haven't seen the movie, either, here you are:

The graph of temperature rise from 1860 to now is pretty standard, but the Elmhurst College Chemistry Department's global warming site (workbook?) says some scientists say there's so much uncertainty in the numbers that it's not good for much. Here are two examples, the first from Elmhurst, the second from a Nova/Frontline collaboration on PBS:



Looking at those graphs as a physicist, I see the general upward trend that goes along with drowning polar bears and melting permafrost, but it doesn't look like the temperature is shooting upward. It looks more like a too-small data sample to see much, so Nova/Frontline's next graph didn't disappoint:


Oh, yeah! It looks pretty clear we're all going to die, until you see this one from NASA:

The purple dotted line in the graph above is our current global average temperature of about 15 C (59 ^oF).

Since NASA is full of good scientists, they have a nice zoom view of recent history, so you can see that the temperature has remained relatively constant over the last 100 years.

But now I have a problem, that as a sixth grader, would probably send me to the teacher for some help. If you look up a couple of graphs, the scary Nova/Frontline graph is for the same years as this NASA graph.

So now it's an issue of where you got your data. Nova/Frontline says scientists got their data from coral, tree rings, sediment, and ice cores, but NASA cites tree rings, ice cores, and geology, so as far as I'm concerned, temperature-watching is useless.

CO₂ is the next place to turn. I understand from the sixth-grader article that since there are volcanoes on Hawaii, that we can completely discount this Nova/Frontline graph:

except for the fact that I have to disagree with them because here, from the description of Dr. Keeling's work on UCSD's global warming site, is the famous Keeling curve:

which is apparently not at all controversial, besides looking pretty smooth to be volcanic.

The result of today's 45-minute study is that

1. I have seen the CO₂ evidence, and I conclude that the climate modeling people are probably our best bet for interpreting it.
2. Anyone, anywhere, who tries to point to temperature trends of any length in either direction as evidence ("the 1960's had a cooling trend!") is totally full of it.

I should fess up here: I don't care if people cause global warming or not. I care that people cause pollution, and after my experience last week, that's gotta stop, and if global warming fears accomplish that, sign me up.