## Thursday, October 04, 2007 ... //

### Svensmark and Friis-Christensen: reply to Lockwood and Fröhlich

The Sun is still alive

Henrik Svensmark and Eigil Friis-Christensen wrote a reply to the article by Lockwood and Fröhlich. Many graphs are extended up to 2007.

I think it is an excellent paper because it seems to give hints how the climate actually works. Look at this extremely impressive correlation captured in their figure 2b:

The blue graph is the radiosonde temperature anomaly - a source of temperature data that Svensmark and Friis-Christensen consider to be the physically "cleanest" source. The word "anomaly" means that the effect of El Nino, the North Atlantic Oscillation, volcanic aerosols, and additional 0.14 K/decade warming trend was removed.

The "hardcore" skeptics will have to swallow the last entry in the previous paragraph. ;-)

The red curve shows the cosmic ray flux (upside-down) as a function of time.

You might agree that the result is quite impressive. The short-term details of the temperature anomaly that are reproduced by the negatively taken cosmic ray flux are arguably non-trivial enough to justify the choice of roughly four coefficients that have to be adjusted to reproduce the curve especially because the value of some of these coefficients are known from other considerations.

Think about a different four-parameter interpolation of some of the data points or about another non-linear regression, if you wish, such as a cubic polynomial or a combination of two cosines with adjustable frequencies and amplitudes. Surely, you wouldn't be able to match the curve so accurately.

If you believe the curve, their work not only seems to show that the cosmic rays influence the climate but it even quantifies the sensitivity on the cosmic ray flux and therefore the slopes. Quantitatively speaking, you can see that cosmic rays are routinely changing the temperature by as much as 0.5 Kelvin degrees per decade - essentially the warming trend attributed to the enhanced greenhouse effect for the whole 20th century.

Their added recent 0.14 +- 0.4 Kelvin per decade trend - the figure is identical to the UAH MSU decadal trend for the lower troposphere (in the middle troposphere, UAH MSU only gives 0.06 Kelvin per decade) - is often conveniently blamed on the enhanced greenhouse effect but the authors of course note that this identification is not proven and alternatives exist.

The origin of the trend may be in changes of the natural greenhouse effect or other low-frequency signals (perhaps some additional signals related to the oceans). Even if you believe that man is creating this contribution, you see that the slopes it gives every decade are roughly 3 times smaller than the trend from the cosmic rays. At any rate, this is the kind of high-frequency precision analysis that climate modelers should be trying to verify, reproduce, and improve.

As reported by Rasmus Benestad, A Norwegian website praised Friis-Christensen for having given the "best speech ever" in the annual Birkeland seminar organized by Norwegian Academy of Science and Letters (NASL).