Expert credibility in climate change?

I recently stumbled upon one of the most meaningless papers I have ever seen. The paper "proves" that the scientists advocating an anthropogenic greenhouse warming (AGW) are statistically more credible than the "unconvinced". Their main goal is to convince people that they should join the AGW bandwagon simply because it is allegedly more credible.

To the hebrew readers of sciencebits לקוראי העברית של סאינס-ביטס

(On the hebrew translation of the "Chilling Stars")

לאור העובדה שלא מעט מקוראי האתר בעברית מתענינים בנושא של השפעת השמש על האקלים, מצאתי לנכון "לפרסם" תרגום לעברית של הספר "chilling stars" של הנריק סוונסמרק ונייג`ל קולדר, שהם ידידי. הספר "הכוכבים המקררים" יצא לאור זה עתה בהוצאת עם עובד.

Earth Day Blackout in Israel vs. Al Gore

A week ago was Earth day, and just like the trend elsewhere, Israel joined with an hour long blackout. In principle, I am very much in favor of environmental awareness, and if it brings some, so be it. But if you ask me, overall, this event is a rather pointless gimmick. Why?

The oceans as a calorimeter

I few months ago, I had a paper accepted in the Journal of Geophysical Research. Since its repercussions are particularly interesting for the general public, I decided to write about it. It's called, using the "Oceans as a Calorimeter to quantify the solar radiative forcing".

Auroras in Lapland

I recently attended the 3rd Space Climate Symposium which took place in Saariselkä, about 250 km north of the arctic circle in Finnish Lapland. Because of the prolonged solar minimum, my hopes were for a high auroral activity, but my expectations were not. Luckily, it was my hopes which were fulfilled!

Here is a summary of the northern lights I have seen.

Is the causal link between cosmic rays and cloud cover really dead??

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?

More slurs from continues with its same line of attack. 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.

Open convection cells over the Negev?

OpenCellRadar 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.

The Hebrew University debate on Global Warming

The panel. From left to right: Prof. Colin Price, Prof. Nathan Paldor, Prof. Dan Yakir, and myself.

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, here is a short synopsis. It is followed by a detailed response to the claims raised against the cosmic ray climate link.

The inconvenient truth about the Ice core Carbon Dioxide Temperature Correlations

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?

Parhelic Circles, Ice Haloes and Sun dogs over Jerusalem

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.

On the IPCC's summary for policy makers, and on getting interviewed without noticing

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!

Climate Sensitivity - an interesting IPCC bias

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 ...