UPDATE 12/3/14: John Fleck wrote to point out his first climate-related blog post was April 2003, and "I almost certainly blogged about climate earlier on my Albuquerque Journal blog, but those archives were lost in one of the newspaper's many computer system overhauls."
People have been talking about early climate blogging on Twitter. Stoat tells what he remembers here.
I really don't know if I was the first climate blogger or not. I think I started blogging in 2002, when I was living in rural New Hampshire in a place with a gas stove for heat and 5 times the best view of Lake Winnipesaukee you can possibly imagine. I didn't have a blogging platform; I coded the HTML by hand, over one of those dial-up modems that, when dialing, sounded like a bad bus crash. I took the name "Quark Soup" from the quark-gluon plasma, something I had worked on in graduate school, and a friend made the picture above of a steaming bowl of quark soup. (I left out the gluons.)
I've searched in the Wayback Machine, but sadly haven't yet found any of my blogging from then. This is the first of my pages it finds, just my simple home page from October 1999. (I started freelancing about a year earlier.) At some point I started using the Greymatter blogging platform, which was a significant improvement except it got to the point of taking up to an hour to recompile after I made a change.
I got broadband in 2003 when I moved to less frigid parts of southern Maine and then coastal New Hampshire. Here's the earliest Greymatter page of mine that the Wayback Machine finds, from March 2003. This post was an early complaint about Mark Steyn. The world was setting temperature records back then, too.
McIntyre and McKitrick did a good deal to advance interest in climate blogging. Here's the earliest mention of them that I can find on by blog, from December 1, 2003. I remember the traffic on my little blog ramped up sharply with postings about M&M. It was clear there was a lot of interest from people wanting to know the very latest information that was available, whatever scraps there might be, and for a little while I was inside the loop because there were no other such outlets, and the blogo
My blogroll from 2003 lists several other bloggers I knew about and/or liked, but only a few were devoted to science:
A Voyage to Arcturus, Calpundit, Cosmic Log (Alan Boyle), Dan Kennedy, Gawker, h20boro lib blog, Matthew Yglesias, Maxspeak, Ted Barlow, Thinking It Through, Three River Tech Review, WampumCan't believe I once liked Gawker, but blogging -- even Gawker -- was then still novel and innocent.
In May 2006 I moved to Blogger, which made blogging life much easier. I got a job blogging for Technology Review for about six months, but didn't surf the blogging wave going forward and didn't head up its power law distribution. I've never been sure why; maybe the things I'm interested in or my style of writing just doesn't make the grade to popular or payable blogging. Or maybe too many pictures of my cats etc.. I'm not so interested anymore in covering the inside baseball of the climate blogosphere, because it's takes too much time to keep up with it all, I try to spend most of my attention on understanding the science better, and plenty of others are doing a fine job of it anyway. What I liked about early blogging was its almost Twitter-like atmosphere -- you could put up a short post just to say you found some article or paper interesting. Now Twitter fills that need, and writing a thorough blog post often requires research and fact-checking, same as my day job. And my nephew and niece now play in a lot of sports leagues.
Added 12/7/14: A commenter found this post from October 2003 titled "Global Warming debate heats up again," and recalls McIntyre's 11/18/2003 presentation on Capitol Hill....