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The sun is quiet ... very quiet.
In February, for the first time since August 2008, the sun went an entire month without any sunspots.
Sunspots are cooler regions of the sun. How many appear on the sun's surface depends on what cycle the sun is in. Every 11 years our star goes through a maximum, followed by a minimum (the entire magnetic cycle of the sun, when the poles flip, is 22 years).
Over the past three decades, the sun has been consistently dropping in activity. Maximum has been quieter than is typical; minimum has been particularly quiet. And this has caused some to make the false assumption that, as a result, Earth is going to cool.
It all stems from an incident that took place between 1645 and 1715, called the Maunder Minimum, where sunspots all but disappeared. This coincided with the "Little Ice Age" that stretched from 1500 to 1850 in the northern hemisphere. In England, the Thames River froze over; Viking settlers abandoned Greenland.
https://www.cbc.ca/news/technology/solar-activity-1.5049337
(Score: 5, Informative) by PiMuNu on Wednesday March 13 2019, @10:59AM (4 children)
> at the moment cosmic ray modulation of Earth’s cloud cover seems rather promising in explaining the size of solar impact
I thought CLOUD experiment at CERN demonstrated this was not the case.
https://home.cern/science/experiments/cloud [home.cern]
My understanding was that even Svensmark has accepted that solar cosmic rays are significant but not dominant in climate. Here is a paper:
http://science.sciencemag.org/content/354/6316/1119 [sciencemag.org]
Cut n paste of top matter for the lazy (emphasis mine):
New particle formation in the atmosphere produces around half of the cloud condensation nuclei that seed cloud droplets. Such particles have a pivotal role in determining the properties of clouds and the global radiation balance. Dunne et al. used the CLOUD (Cosmics Leaving Outdoor Droplets) chamber at CERN to construct a model of aerosol formation based on laboratory-measured nucleation rates. They found that nearly all nucleation involves either ammonia or biogenic organic compounds. Furthermore, in the present-day atmosphere, cosmic ray intensity cannot meaningfully affect climate via nucleation.
(Score: 2) by PiMuNu on Wednesday March 13 2019, @11:23AM (3 children)
I didn't make it clear in parent, Svensmark was not author of paper I quoted, rather it was CLOUD collaboration.
(Score: 0) by Anonymous Coward on Wednesday March 13 2019, @11:42AM (2 children)
That document I linked is from 2019 and it cites stuff from 2018 but not that 2016 paper you linked to. He does discuss the CERN CLOUD project on page 13-14 though. I see there he is claiming the effect of the cosmic rays is on the growth of already nucleated particles, not nucleation rates like Dunne 2016 talks about.
(Score: 2) by PiMuNu on Wednesday March 13 2019, @12:22PM (1 child)
> That document I linked is from 2019
Interesting. I found this publication by Svensmark et al:
https://www.nature.com/articles/s41467-017-02082-2 [nature.com]
referenced from here if you can't see through nature paywall:
https://scitechdaily.com/how-cosmic-rays-from-supernovae-influence-earths-cloud-cover/ [scitechdaily.com]
which supports your argument.
(I am a terrible person so I tend to ignore the "some guy wrote something on the internet" and go for the journal papers instead. I don't believe the journal papers, but at least they have passed someone's credibility threshold and are not cranky nonsense).
(Score: 0) by Anonymous Coward on Wednesday March 13 2019, @12:30PM
Svensmark was the author of that document, so if you trust his journal articles to be non-cranky you can trust that as a high level review.