Anyone who regularly tunes into WattsUpWithThat.com, the popular climate-science blog operated by Anthony Watts, will never make fun of TV weathermen again. Watts - who was a TV meteorologist for 25 years - provides a steady diet of smart, always interesting and sometimes deeply complex scientific information and opinion about global climate change. Watts is also the founder of surfacestations.org, a project that for nearly two years has been quality-checking each of the 1,200-plus weather stations of the U. S. Historical Climate Network (USHCN) to see if they are set up and maintained properly. So far, Watts and his volunteers have checked about 820 of the weather stations, which have been in place for about 100 years and are the source for the country's official average annual temperature. Watts has found that temperature data from nearly 70 percent of the stations is of questionable accuracy because the stations do not adhere to the USHCN's own quality-control guidelines. I talked to Watts April 16 by phone from his office in Chico, Calif.

Q: Why do you do your blog WattsUpWithThat?

A: Well, it's just an extension of what my life has been up until the last few years. I was a broadcaster on television - a meteorologist - for 25 years. I look at the blog as really no different. I did a daily broadcast each day in television. A blog is really just a daily broadcast in a different form.

Q: Who is your target audience?

A: I never really thought about a target audience. I took the same philosophy from broadcasting. I made it to reach as broad an audience as possible and the demographics that I get from it tell me I am doing that job successfully. I've got everything from people with high school educations to people that are Ph.Ds who are reading and commentating and sometimes even submitting articles.

Q: Sometimes it gets pretty deep - lots of scientific charts and data.

A: It does. But that is to be expected because of the broad audience we have. My job is to try to make everything understandable, even for people who are not in tune with some of the more technical details of climate.

Q: Have you become more politicized since you began blogging? Or are you primarily still a man of science?

A: Well, my main interest always has been the science. I am still of the belief that you should let the data tell you what the real story is. As far as the blog goes, the only thing I can say that I've become a little more critical of in terms of politics is that we have some people now who should be sticking to science, such as Jim Hansen (head of NASA's Goddard Institute for Space Studies, going out and advocating things such as civil disobedience (at coal-fired power plants). That concerns me.

Q: What is your basic position on the question of global warming? Are you a believer? A skeptic? Somewhere in between?

A: I would call myself what some people describe as a "lukewarmer" in that the CO2 effect that people have done thousands of studies on is in fact real. However, it is not a crisis. The reason it is not a crisis is because most people do not understand the logarithmic nature of the CO2 response in our atmosphere.

Q: And that means?

A: It's like salting soup. If you have a bowl of soup in front of you and you put a little salt in it to salt it to taste, you say, "Well, maybe it needs just a tad more." So you add some more salt and you think, "Maybe not quite enough." Then you add some more, and all the sudden it's too salty. Now if you were to add additional salt to the soup, you could not determine that it was any more salty than it already was. And if you continue to add salt, you can't tell the difference.

CO2 is much like that in the way that our atmosphere responds to long-wave outgoing radiation, or trapping of heat. At some point when you get to a certain level, like a doubling of CO2, and then you add a second doubling of CO2, the response halves. It's logarithmic. Then it halves again and then halves again after that. So much of the effect that we would expect to see from CO2 -- because of this logarithmic response -- has already happened. In essence, our soup is already fairly well salted and additional salting is not to make a whole lot of difference.

Q: What is the most harmful "fact" - quote unquote - about global warming that everyone believes but which is probably not true or at least uncertain?

A: There is a belief out there that we will get into a runaway condition where at some point a tipping point would occur and that at that point there is no turning back and then the world would destroy itself. That is being pushed in the media a lot and it is flat wrong.

As we go back into history, into past millennia, we can see that our atmosphere has in fact had much more CO2 - up to 6,000 parts per million, compared to the 380 parts per million that we have now - and it has responded and it has settled. Earth didn't destroy itself. It didn't burn up and boil off the oceans. So the comparison that we see with runaway global warming and the turning of Earth into Venus, things of that nature, are probably the most dangerous and wrong ideas that are being pushed.

Q: Are your troubled or annoyed by the way global warming is being discussed or covered by the mainstream media?

A: I am. And mainly because it's getting a free pass for almost every problem that's brought up. There's a Web site in the UK called Number Watch (numberwatch.com) that maintains a list of literally thousands of things in the media that are blamed on global warming. It's almost like "The Devil made me do it." The idea here is that, yeah, we have an issue and the issue is that there is some warming of the atmosphere.. That warming however is not catastrophic. It has occurred in the past and the Earth has survived. So the blaming of global warming as a catchall for every problem that we see in our environment is a disservice to science and to the people.

Q: My grandchildren ask me if the polar ice in the Northern Hemisphere is going to disappear?

A: I would say that the polar ice has disappeared in the past. Certainly there seems to be evidence of past climate situations where we may have had virtually no or none during the summertime. In the immediate future, however, I don't think we are going to see that. In fact, we're going through a rebound right now. If you look at the current Arctic ice extent from the Japanese agency which tracks the Arctic ice, you'll find that it is very near normal at this point and it is rebounding well from the last couple years. Antarctic ice is above normal. And the global total amount of sea ice is above normal. So it's not disappearing any time soon.

Q: What's the story with the Sun? It's been described as being asleep or in a state of "slumber" because it has had virtually no sun spots for a long time. What's going on?

A: Well, the Sun is driven by dynamic magnetic cycles. There are 11-year and 22-year cycles that have been identified and there are longer cycles that have been theorized. In every kind of a cycling endeavor there are always lulls and there are giant peaks. We've seen both in the past. We've seen lulls in the Maunder Minimum (1645 to 1715) and the Dalton Minimum (1790 to 1830), when virtually no sun spots appeared. Coincidentally, during those periods the weather and climate on Earth got colder. Continued...