Henrik Svensmark on Cosmic Rays, Clouds and Climate
In June 2026, during the 17th EIKE conference in Halle, Germany, my colleague, Dr. Willie Soon and I, took the opportunity to meet with Dr. Henrik Svensmark for an extended discussion of his research on cosmic rays and climate
We also talked about the personal and professional challenges of following the science where it leads when the science leads to politically incorrect results, i.e., finding evidence that much of the climatic change since the Industrial Revolution might be due to natural factors rather than human-caused.
Indeed, at the end of the interview, he revealed that he had just been fired by his former employer.
Svensmark’s Sun-Climate Theory
Svensmark has spent more than two decades investigating a chain of physical processes that he argues begins with solar activity and ends with cloud formation.
It is known that high solar activity strengthens the solar wind, which reduces the number of galactic cosmic rays (GCRs) reaching Earth’s atmosphere. On the other hand, low solar activity weakens the solar wind and thereby increases the amount of cosmic rays reaching the Earth.
Svensmark argues that these cosmic rays can help form cloud condensation nuclei (CCN) through ionization. He concedes that cosmic rays are just one contributing factor to cloud formation.
But, he argues that it is a significant factor and that when there are more cosmic rays, this can significantly increase cloud cover – especially low-level cloud cover in isolated ocean regions.
In general, more clouds makes the planet a bit cooler. So, he proposes that this can be an important driver of climatic changes:
- Quiet Sun → Weaker Solar Wind → More Cosmic Rays → More Clouds → Global Cooling
- Active Sun → Stronger Solar Wind → Less Cosmic Rays → Less Clouds → Global Warming
Fired For Following The Science
Multiple proxies for solar activity have confirmed that solar activity has increased since the 19th century, i.e., during the period since the Industrial Revolution.
So, he argues that at least some of the “global warming” that the UN currently attributes to human-caused ‘greenhouse gas’ emissions might instead be due to his mechanism. Indeed, as we discussed in the interview, the UN’s current climate models fail to adequately consider his mechanism.
However, while scientifically, he has found his research exciting and rewarding, the fact that his findings are politically incorrect meant his work has hurt rather than helped his professional scientific career, including the fact that he was fired 14 days before the interview.
The full interview runs approximately 40 minutes and covers the science in greater depth, along with the wider context of how this research has been received.
You can watch the video version on Youtube here:
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