That's a very old BBC article (2004). There's quite a lot of information out there since then that disputes these findings. For example, have a look at here for starters. That's not to say that the sun doesn't have some effect, but it's more likely that the human-C02 view is still the best bet.

FF --

The article I linked to says:

Over the past 20 years, however, the number of sunspots has remained roughly constant, yet the average temperature of the Earth has continued to increase.

So I don't really think it's in conflict with any new findings over the past three years, although the article you linked indicates that it's probably been more likely 50 years since there's been a bump in the amount of sun spots. This discrepancy is not unlike the fact the temperatures warmed considerably more in the first half of the 20th century, when carbon emission levels were lower, than they did in the seconbd half.

Didn't notice the date on the BBC article. It was linked from a brand-new Slashdot piece. Apparently the scientists in Zurich haven't backed down from their conclusion that sunspots are at a 1000-year high.

The solar flux variation is too small to have much of an effect. What happens is that the sunspot cycle correlates with solar magnetic activity. The solar magnetic activity induces geomagnetic activity. Geomagnetic activity alternately shields the earth from cosmic radiation during the active portion of the sunspot cycle, and when solar activity is at a minimum (like right now), cosmic 'rays'(solar, Milky way, deep space) penetrate the atmosphere and nucleate clouds. The clouds result in albedo change and cooling.

The subtlety is this: The peak frequency of the sunspot cycle correlates at 95% with global cooling and warming. The two key papers come from the Danish National Space Center (DNSC). The 1991 paper in Science by Friis Christiensen and Lassen pointed out the high correlation of climate with peak frequency: cooling and warming. And the causation link by Svensmark et al, also DNSC, published in the Journal of the Royal Society of London (2006)experimentally proved a link between cosmic radiation and cloud formation. This is a possible explanation for the correlation between the Maunder Minimun and the Little Ice Age.

The correlation between CO2 and global warming is poor to negative likely because the IPCC CO2 data is fatally wrong. But that is another fresh story From Beck... Google Beck and CO2 analyses.

Since the last thirty years has seen the fastest increase in temperature, why is there no correlation over the same period of time in solar irradiance? The World Radiation Centre indicates no increase since 1978 (the year satellite measurements started). In fact, the trend since 1960 seems to be downwards in terms of sunspot numbers.

With regards to Friis Christiensen and Lassen's paper, there has been work since that questions the handling of their data (and the same goes for their subsequent 2000 paper). The accuracy of Svensmark's work has also been questioned.

I'll have a look out for Beck's analyses.

Fran --

Interesting reading, that Beck article. I take it as a given that he will be refuted. What will be telling will be the tone this takes. It's one thing for someone to come along and explain why the data he is referencing is incorrect, quite another to denounce him as a flat-earther and a tool of the oil companies. Care to guess which treatment he'll get?

FF --

Interesting picture. It would appear that CO2 emissions rose steadily from 1900-1940, then dropped sharply between 1940 and 1950, and that emissions never got back to 1940 levels until the late 70's. That can't be right, can it?

Also, the CO2 hypothesis seems to leave a major question unanswered -- why are Mars and Jupiter (and other spots in the solar system) heating up at the same time we are?

Regarding the graph, it is illustrating temperature over time, not C02 emissions. The cooling period of the late 1940's - 1970's (as well as some other "dips") is believed to have been caused by a process called Global Dimming. AFAIK, CO2 during this period rose.

With regards to Mars, a recent study claims that the warming is due to dust storms on the planet. Couldn't tell you anything about Jupiter, though. I believe Pluto is also supposed to be warming, maybe others (a quick Google would probably show what is supposed to be warming and what's not).

Truth is, I don't see how this data of other planets should be trusted over what we know about the earth. Much of the data regarding Mars, Jupiter etc. is woefully incomplete and almost certainly highly inaccurate; we know considerably less about weather systems on foreign planets compared to what we know about the earth's climate.

With Mars, for example, unless there's more data available that I'm not aware of, the idea that it's going through a period of warming is based a few photographs of one region over a two (earth) year period, which seems insane to me for anyone to draw conclusions. Pluto is even riskier, because it hasn't even completed one orbit of the sun in the last 150 years, and we know even less about its weather than Mars.

Now, the Beck paper on the other hand looks very interesting. I'll be looking out to see what response it gets. I would be upset if people attack the messenger rather than the message. Sceptics are vital for good science.

Hmm, posted a response to this a while ago, but it still hasn't appeared. Dunno why, a glitch in the machine probably.

Anyway, the short version of what I wrote (since I can't spend time finding all the links again):

1. If Beck does have a conflict of interest in funding, then it should be noted. That's just good sense. At the same time, however, if his actual science is not questioned then that is obviously a very bad thing. Sceptics are certainly necessary in science in order to validate or invalidate hypotheses. I would be extremely unhappy if the messenger was attacked, and not his message.

2. The picture is not showing CO2, but temperature. The decrease in temperature you seen is believed to have been caused by a process known as global dimming (check out Wikipedia and elsewhere for more on this).

3. Mars' global warming may be caused by dust storms (Google "dust storms" mars warming).

Regardless, talking about what other planets are doing seems to me to be incredibly risky. For example, Pluto still hasn't completed one revolution of the sun in the last 150 years and we've hardly got any serious data on its (or any other planet's) weather system in comparison to the incredible amounts of data we have on earth's weather systems. Using this as a basis to draw conclusions seems crazy.

Another example: as far as I know, the talk about Mars' "global warming" seems to be based on a few photographs of one region of Mars. Imagine if climate scientists turned around and said that their ideas of Global Warming on earth were based on a couple of pictures of our south pole over just a few years. I seriously doubt people would accept this is definitive proof.

FYI, I know this article has gone down the list and no-one's commenting anymore, but I thought you'd be interested in this very good rebuttal of Beck's work.