ScienceBits

The site has undergone a facelift to cure a few maladies. Expect some hiccups.

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.

התחממות גלובלית, מי יודע מדוע וכמה? A short "open letter" in hebrew about global warming. To all my english readers, sorry. This is a one time quirk.

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.

A few astro photographs, including one of Saturn under horrible seeing!

A few weeks ago, while debating the issue of global warming with an alarmist, my colleague pointed out two facts which appear to be consistent with the "standard" anthropogenic scenario, but not the one I advocate, that the natural climate drivers are large and that Earth's climate sensitivity is small.

Although I knew for quite a while why the first point he raised is meaningless, I must confess that I was a little bothered with the second point. Alas, it was in vain. It turns out that both are fine exemplars for how IPCC science is plain bad.

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?

The recent discovery of a terrestrial like planet (i.e., one which is stony and not gaseous like Jupiter) gave rise to a minor media hype, with statements like "We may be witnessing the start of a cosmic real estate boom" being commonplace. However, is Gliese 581C really a place you would like to call home at any point in the future?

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.

For the few who were wondering about the low activity and slow response to comments... I am busy this semester with teaching two courses, one of which is new (on fluid mechanics), so between preparing clear class notes and trying to continue research, my sciencebits.com response time has slowed down. Rest assure, it is only temporary.

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 pondered about the effects that mass hysteria could have on a flu epidemic. In particular, on how a fright about flu vaccination (which happened in Israel a few months ago) would cause less people to be vaccinated, and thus be responsible for a larger flu outbreak. A recent news item, though, made me rethink.

Alleged paranormal phenomena tend to pop-up from time to time. The best example is probably that of Uri Geller. He became famous in the 70's with his "abilities" to bend spoons, read thoughts, etc. Unfortunately, Uri Geller decided to return back to his native Israel, and worse, got a prime time television program, presumably to find an heir.

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 ...