No Effect

From James Annan, climate scientist:

Do solar/heliospheric changes affect the earth's climate?

That was the title of the keynote talk at a workshop held here last week. To save you the trouble of reading any further, I should just say now that the answer provided was "no, at least not to any significant extent since the middle of last century".

I may play around later with Inhofe's updated (650 scientists!) list of deniers. But one of the new names on the list is Oliver "Iron Sun" Manuel, who I have previously written about here.

Solar Cycle 24 Seems To Be Underway

Oh My! Note the black speckle top left. Predictions of global cooling based on a lack of sunspot activity area seem about to go out the window.

Apparently, the real scientists who predicted that this quiet period was not unprecedented got it right after all.

Quiet Sun No Big Deal

Anthony Watts has been toying with this one for awhile: Its all quiet on the solar front. Too quiet.

And other some have been even more direct: no/few sun spots = dangerous global cooling.

The sun undergoes cyclical changes on multiple time scales that appear to correlate very well with temperatures. Long and relatively quiet solar cycles historically have been associated with cold global temperatures, short and very active cycles, warm periods. The current cycle 23 appears to be the longest in at least a century and may project to quieter subsequent cycles and cooling temperatures ahead.

Except: how unusual is a situation like the current one really? Not very, according to NASA's David Hathaway:

"There have been some reports lately that solar minimum is lasting longer than it should. That's not true," said NASA solar physicist David Hathaway. The ongoing lull in sunspot numbers "is well within historic norms for the solar cycle.

"The sun has been relatively quiet for more than two years. Hathaway said there were stretches in the 20th century when the slack periods lasted twice this long.

"It does seem like it's taking a long time," Hathaway said, "but I think we're just forgetting how long a solar minimum can last."

And here's a chart that compares the latest minimum in terms of "spotless days" to the 1933 minimum. Contra D'aleo (2nd quote above) our current quiet period is not even close to being the longest observed minimum this century:

Another way to examine the length and depth of a solar minimum is by counting spotless days. A "spotless day" is a day with no sunspots. Spotless days never happen during Solar Max but they are the "meat and potatoes" of solar minima.

Adding up every daily blank sun for the past three years, we find that the current solar minimum has had 362 spotless days (as of June 30, 2008). Compare that value to the total spotless days of the previous ten solar minima: 309, 273, 272, 227, 446, 269, 568, 534, ~1019 and ~931. The current count of 362 spotless days is not even close to the longest.

Cycle that, Anthony.

If The Temperature Does Not Soon Recover

...we will have to conclude that global warming is over.

Except that, by Phil Chapman's own methodology*, it already has recovered: Global land temperature in March sets record

Huzzah! The WLIA ( Wee Little Ice Age) is over.

*Not that I approve of his methodology, which is to compare one month temps (January to January) from this year to last. That tells you almost nothing.

But hey, gotta fight fire with fire.

No Solar Link Redux, Redux

Research has thrown further doubt on the notion that cosmic rays are a major influence on the Earth's climate.

This is very similar to recent work by Sloan and A.W. Wolfendale, which I noted here; its lead author ( Jon Egill Kristjansson) suggests that if a theory like Svensmark's is true (cosmic radiation drives cloud formation drives average temperature increases/decreases on Earth) then

...sudden changes in cosmic ray intensity should ...[produce]... increases in cloud cover, changes in the size of droplets, and possibly in the total amount of water carried in the clouds.

The author(s) see no such changes, therefore conclude that the theory is not likely to be true.

I should note that the first Sloan/Wolfendale paper inspired this critical response from Israeli astrophysicist N.J. Shaviv, which prompted a rebuttal (exclusive to this blog) from Terry Sloan himself.

Yeah, we're about more than fighting Nazis at BCLSB.

On Solar Links: Sloan Responds To Shaviv

Earlier in April, Terry Sloan and A.W. Wolfendale published a paper in which they offered an apparent refutation of Henrik Svensmark's theories linking solar activity to Global Warming. The paper is here, my post on it here. Yesterday, astrophysicist N.J. Shaviv published an on-line critique in which he suggests that Sloan and Wolfensdale have made three mistakes in their paper:

Two arguments are based on the expectation for effects which are much larger than should actually be present. In the third argument, they expect to see no phase lag, where one should actually be present. When carefully considering the link, Sloan and Wolfendale did not raise any argument which bares any implications to the validity or invalidity of the link.

I contacted Terry Sloan yesterday afternoon via email and asked him if he would like to respond to Mr. Shaviv's arguments, and he asked me to post the following:

Dear Shaviv,

I would like to correct the factual errors in your blog.

1. Concerning cosmic rays. Muons, neutrons and the soft component of cosmic rays are all produced from the interactions of the primaries in the upper atmosphere. So the thickness of atmosphere above them is irrelevant. This is a factual error in your paper.

You say we should have compared with ionization chamber data - no such long term data exist either for shielded ion chambers (only sensitive to muons) or unshielded (sensitive to ionization from both muons and electrons). If such data had existed we would have used them.

The Ususkin et al computations of the solar modulation of the total ionization in cycle 22 are compatible with our neutron monitor curve. So our analysis is safe.

2. Your fig 2 from the other Usoskin et al paper is for a highly selected data sample with a large correlation coefficient - not the global average with which we compare. Hence your fig 2 has little to do with our analysis using global averages. We stuck to global averages because in the original Marsh and Svensmark work they computed from the globally averaged dip in cycle 22 that the radiative forcing was 1.4 W m^-2 if all the dip was caused by CR. We set out either to confirm whether the dip was due to CR or not and if not to set a limit on the fraction of it which could come from this source. As we could find no corroborative evidence that it was due to ionization we set a limit. Our limit says that the radiative forcing cannot be more than 23% of 1.4 W m^-2.

3. Forbush decreases - the changes in the CR rate were averaged over the same time intervals as the changes in the LCC - so we have done this correctly and not incorrectly as you imply. The Forbush decreases usually take place over times between days to a month.

Regards, Terry Sloan.

No Solar Link

All sorts of blogging on this story, re. the apparent refutation of Henrik Svensmark's theory linking solar activity to Global Warming. I can't add much to them, other than noting that the actual paper behind all the fuss is here , if anyone wants to get down and sciency.

In short, Svensmark's theory says that increases in solar activity (measured by sunspot numbers) drives an increase in the force/velocity of the solar wind, which in turn sweeps away Cosmic Ray particles that might otherwise reach Earth's atmosphere. Cosmic radiation in Earth's atmosphere drives ionization, which drives low cloud cover (LCC). Thus, high levels of solar activity mean low levels of sunlight-reflective LCC, from which follows an increase in global mean surface air temperatures (Global Warming).

So states the theory.

What U.K. physicists T. Sloan and A.W. Wolfendale did was to locate short term increases/decreases in CR intensity in existing data sets (Forbush decreases, for example), and look around for corresponding changes in LCC indexes. They didn't find any.

Note that this does not necessarily refute the notion of a correlation (or, more accurately, anti-correlation) between sunspot numbers and LCC. It simply shows that this cannot be caused by atmospheric ionization, as postulated in Svensmark's theory.

Solar Kismet

Today both Ezra and Greg from The Politic try to retail the same bit of nonsense about global warming on planet Earth being primarily sun-driven. Their evidence? A similar phenomenon appears to be occurring on Mars. However, on the very same day they makes these claims, an honest-to-goodness scientific paper appears that refutes them:

Mars is a very windy place--so windy, in fact, that bright, oxidized martian soil is being scoured away by martian winds and dust devils to reveal darker, sub-surface soil with the end result of making the whole planet warmer. Mars is experiencing its own brand of climate change. Is this related to planet earth's greenhouse gas driven climate change? No. Is understanding the process important for our understanding of how planets evolve and change over time? Absolutely.

The post from Greg at The Politic seems particularly dishonest, as the article he quotes from actually includes the same explanation of the Martian warming phenomenon as is given above. Or perhaps Greg has ADD and is incapable of reading a newspaper article to the very end.

Incidentally, when you hear these stories about Global Warming on Mars, or Titan, or Pluto being proof that the same phenomenon on Earth is due to "solar cycles", just remember, you don't have to look at Mars or Pluto to see what the Sun is up to. You can simply take direct measurements of the Sun itself, as these people have been doing for years. And guess what? Solar output has remained more or less constant during this time.