Just recently, Sloan and Wolfendale published a paper in Environmental Research Letters, called "Testing the proposed causal link between cosmic rays and cloud cover". In the Institute of Physics Press Release, it said, "New research has deal a blow to the skeptics who argue that climate change is all due to cosmic rays rather than man made greenhouse gases". Did it really?

Realclimate.org continues with its same line of attack. Wishfulclimate.org writers try again and again to concoct what appears to be deep critiques against skeptic arguments, but end up doing a very shallow job. All in the name of saving the world. How gallant of them. This time it is an ill-founded attack by Jahnke and Benestad.

Jerusalem was under siege, again. Last time it was Bush. This time, it was snow because of which we had two snow days. So, I didn't have to teach and instead could build a snowman with my kids. I could also look at the rain radar, which appeared to exhibit a few interesting phenomena.

One of the phenomena appears to be that of open-cell convection, i.e., air rising (and precipitating) on the cell boundaries.

On Sunday last week, a global warming debate was held at the Hebrew University, in front of a large public audience. The speakers included myself, and Prof. Nathan Paldor from the HU, on the so called sceptic side, and Prof. Dan Yakir (Weizmann) and Prof. Colin Price (Tel-Aviv Univ.) on the anthropogenic greenhouse gas (AGHG) side.

You can watch the debate, in Hebrew at the Authority for Community and Youth of the Hebrew University. Since most of the readers are not from Israel (98% of the visitors to sciencebits.com), here is a short synopsis. It is followed by a detailed response to the claims raised against the cosmic ray climate link.

On of the interesting manmade climate phenomenon is that of Ship Tracks, whereby a ship, with all the exhaust particles it releases, can change the characteristics of clouds in its wake. Last week, I saw first hand how a boat can pollute so much.

One of the "scientific" highlights in Al Gore's movie is the discussion about the clear correlation between CO₂ and temperature, as is obtained in ice cores. He leads his audience to beleive that this correlation implies a clear CO₂→ΔT link, but does it really?

A few weeks ago, a few students saw a nice phenomenon in the sky. Knowing I liked this kind of stuff (and that I may be able to explain it), they called me out of the office to look at the sky. Above us was a nice and almost complete parhelic circle. Unlike the usual 22° halo, often seen around the moon and occasionally around the sun, the parhelic circle keeps a fixed angle from the horizon, not from the bright object.

Yesterday, I noticed (and photographed ) Kelvin-Helmholtz Clouds forming in Jerusalem's sky. This instability arises when very large shears are present in the velocity fields, in this case, just below the jet stream.

Yesterday I was surprised to find out that the IPCC didn't really come out with the Fourth Assessment Report (4AR). I was also surprised to find an article with something which appeared to look like an interview of me. Since I am not senile (getting there, but not just yet) I found it strange that I didn't remember actually being interviewed!

Some time ago, I noticed an interesting bias in the TAR scientific report (the third assessment report of the IPCC - the intergovernmental panel for climate change) regarding the climate sensitivity, that is by how much the average global temperature will increase if we double the amount of CO₂. The report mentions quite a few times that climate sensitivity "is likely to be in the range of 1.5 to 4.5°C". Why is this interesting? Because ...

What is climate sensitivity?

The equilibrium climate sensitivity refers to the equilibrium change in average global surface air temperature following a unit change in the radiative forcing. This sensitivity (often denoted as λ) therefore has units of °C/(W/m²).

Often, instead &\lambda;, the sensitivity is expressed through the temperature change &Delta T_x2, in response to a doubled atmospheric CO₂ content, which is equivalent to a radiative forcing of 3.8 W/m². Thus, &Delta T_x2 = 3.8 W/m² λ

After a long embargo, results from the Danish National Space Center (DNSC) Sky experiment were finally published in the Proceedings of the Royal Society. The results demonstrate a clear link between cosmic ray induced atmospheric ionization and the formation of condensation nuclei, thus strengthening the claims that cosmic rays affect cloud cover and climate (and consequently implying that a large fraction of 20th century global warming should be attributed to the increased solar activity).

Last week, a report by Jeff Kanipe appeared in nature. In it, Kanipe explains the solar → cosmic-ray → climate connection, and the planned CLOUD experiment in CERN, expected to finally resolve the issue. Given that my work is mentioned in the review, I through I should mention a few relevant points.

Here are some pictures and a physicists take of a fantastic hail storm which took place west of Jerusalem in October 2004. The largest stones were up to 5 cm in diameter and several car windshields were shattered!

A few days ago I stumbled upon an interesting article from Time magazine, entitled: "Another Ice Age?". No it is not a recent article. It is politically incorrect to talk about global cooling these days. The article appeared in 1974, after "three decades of cooling" prompted some to believe that an imminent ice-age may be coming. It is interesting to read it in perspective, and perhaps there is a lesson we could learn from it. Here are a few excerpts from it. Read and enjoy.