Hi all,
You may or may not have seen the water dimer diary I did that remarkably went to the top of the list. Well, here is an update. The reason I am posting about water dimer is that it is a little known component of global warming that may have a big effect. It is not the dihydrogen monoxide pollutant that was meant to be banned in a petition that once went around. H2O is real and so is (H2O)2. For every 1000 molecules of water in the air there is about 1 pair of water molecules stuck together in what is called water dimer. One of the things I did in my paper is measure that relationship. The other is that I measured the strength of the absorption and it is 1000 times stronger than the best calculations predict. Maybe that means it is a mistake, but I did careful measurements and I am confident that other researchers will measure water dimer with visible light when they try.
My paper is now online at
Atmospheric Chemistry and Physics Discussions
If you thought my previous diary was hard to read you should see when I am writing to a technical audience. My paper was reviewed well for its importance and scientific merit, but they thought I was a lousy writer. Please don't comment on ACPD unless you have an academic point to make. I came here to discuss this paper as well because the consequenses really are serious. I will need to be able to explain my results to a skeptical audience and the more practice I get the better.
In the diary that broke the other day (click on my user name to see my diary and others I wrote) the comments brought out the topic quite well, despite the presence of nay-sayers that attacked on every weakness and opportunity. I have a better understanding even myself and I encourage you to look it up.
To summarize... Water dimer vapor absorbs visible light. Not so much that it is easy to see, but enough that it will affect the models that show global warming. It doubles the 20 year projection of global warming, which according to Albert Arking is about 7 deg F (I am using Farenheight because Americans are used to it) In celcius that is about 4 degrees C. I think the reference is actually one I don't have handy... Arking wrote it in about 2003 or 2005 on the sensitivity of global climate change to water dimer. (Yes, I am lazy. I will bet someone comes up with the exact link in the comments. Here is your challenge.)
Water dimer is a feedback mechanism, not a greenhouse gas, meaning that it is not a source of the problem that we contribute, it just makes it worse. As temperatures go up, humidity will tend to go up and water dimer will go up too. It is almost by the square of the absolute humidity.
What we do about it is a harder question. I think we need a carbon tax to replace the income tax. That would be the best thing we can do politically, and after all, this is a political blog. If you want something you can do personally, replace your lightbulbs if you haven't already. If you can get LED lightbulbs yet they are even better. I drive a Prius and I will be getting the plug in battery range extension when it comes out. We need to get over the feeling that we are safer up high in an SUV. They have worse safety performance and you will just roll over if you aren't lucky. If you have lots of kids buy two hybrids.
Another thing we can do is really go after methane emissions. The gas company has been doing that for about 15 years but only as a CYA kind of thing. We need to do better.
I realize that my writing may seem dense, but I will be back in a few minutes to answer any questions.
Cheers,
UCR James