Finally! The missing link between exploding stars, clouds and climate on Earth

Our new results published today in nature communications provide the last piece of a long studied puzzle. We finally found the actual physical mechanism linking between atmospheric ionization and the formation of cloud condensation nuclei. Thus, we now understand the complete physical picture linking solar activity and our galactic environment (which govern the flux of cosmic rays ionizing the atmosphere) to climate here on Earth though changes in the cloud characteristics.

The Sunspots 2.0? Irrelevant. The Sun, still is.

After being asked by 5 independent people about the new sunspot number reconstruction and that it doesn’t show that the sun should have contributed any warming to the 20th century, I decided to write about it here. I have one word to describe it – irrelevant. It is also a good opportunity to write about new results (well, one that saw the light of day a few months ago) showing again that the sun has a large effect on climate. Yet, the world will still continue to ignore it. Am I surprised? No I’m not.

Sights from a Field Trip in the Milky Way: From Paleoclimatology to Dark Matter

32 million year oscillation in the paleoclimate data
I was recently asked to write an article to “The Institute Letter” of Institute for Advanced Study at Princeton, where I am spending a wonderful sabbatical year. It briefly describes a very interesting discovery that my colleagues and I made, which is that the 32 million year oscillation of the solar system perpendicular to the galactic plane can clearly be seen in the paleoclimate data. In the article, I also discuss how the discovery came and some of its implications. I am bringing a slightly expanded version here (with more figures and elaborated caption), and references of course. Enjoy.

The CLOUD is clearing

The CLOUD collaboration from CERN finally had their results published in nature, showing that ionization increases the nucleation rate of condensation nuclei. The results are very beautiful and they demonstrate, yet again, how cosmic rays (which govern the amount of atmospheric ionization) can in principle have an affect on climate.

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.

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.

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.

Earth's magnetic field protecting us from deadly radiation - A common misconception

Blog topic: 
From time to time, I hear the statement that Earth's magnetic field is important because it protects earth from "deadly" radiation, and that when the magnetic field will reverse, this lethal radiation will be... very bad. One such example is this promo for a NOVA program called "magnetic storm". Well, I have news. Nothing really bad will happen to us!

"SKY" experiment demonstrates link between cosmic rays and condensation nuclei!

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).

Comments on nature's "A cosmic connection"

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.