Editing Solar cycle (section)

==== Clouds ====
Speculations about the effects of cosmic-ray changes over the cycle potentially include:
* Changes in ionization affect the aerosol abundance that serves as the condensation nucleus for cloud formation.<ref name="Tinsley2004">{{Cite book|contribution = Atmospheric Ionization and Clouds as Links Between Solar Activity and Climate|first1 = Brian A.|last1 = Tinsley|first2 = Fangqun|last2 = Yu|year = 2004|volume = 141|pages = 321–339|editor1-first = Judit M.|editor1-last = Pap|editor2-first = Peter|editor2-last = Fox|title = Solar Variability and its Effects on Climate|isbn = 978-0-87590-406-1|contribution-url = http://www.utdallas.edu/physics/pdf/Atmos_060302.pdf|publisher = [[American Geophysical Union]]|series = Geophysical monograph series|bibcode = 2004GMS...141..321T|doi = 10.1029/141GM22|citeseerx = 10.1.1.175.5237|access-date = 2015-08-10|archive-date = 2007-06-04|archive-url = https://web.archive.org/web/20070604183050/http://www.utdallas.edu/physics/pdf/Atmos_060302.pdf}}{{cite web
 |url=http://www.utdallas.edu/physics/
 |title=Department of Physics – the University of Texas at Dallas
 |access-date=2015-08-10
 |archive-url=https://web.archive.org/web/20150815202558/http://www.utdallas.edu/physics/
 |archive-date=2015-08-15
 }}</ref> During solar minima more cosmic rays reach Earth, potentially creating ultra-small aerosol particles as precursors to [[cloud condensation nuclei]].<ref name="CERN Clouds">{{cite press release|title=CERN's CLOUD experiment provides unprecedented insight into cloud formation |publisher=[[CERN]] |url=http://press.cern/press-releases/2011/08/cerns-cloud-experiment-provides-unprecedented-insight-cloud-formation |date=25 August 2011 |access-date=12 November 2016}}</ref> Clouds formed from greater amounts of condensation nuclei are brighter, longer lived and likely to produce less precipitation.
* A change in cosmic rays could affect certain types of clouds.<ref>{{Cite journal |last1=Kumar |first1=Vinay |last2=Dhaka |first2=Surendra K. |last3=Hitchman |first3=Matthew H. |last4=Yoden |first4=Shigeo |date=2023-03-06 |title=The influence of solar-modulated regional circulations and galactic cosmic rays on global cloud distribution |journal=Scientific Reports |language=en |volume=13 |issue=1 |page=3707 |doi=10.1038/s41598-023-30447-9 |issn=2045-2322 |pmc=9988889 |pmid=36878955|bibcode=2023NatSR..13.3707K }}</ref>
* It was proposed that, particularly at high [[latitude]]s, cosmic ray variation may impact terrestrial low altitude cloud cover (unlike a lack of correlation with high altitude clouds), partially influenced by the solar-driven interplanetary magnetic field (as well as passage through the galactic arms over longer timeframes),<ref name="shaviv2005">{{Cite journal |title = On climate response to changes in the cosmic ray flux and radiative budget|journal = Journal of Geophysical Research|volume = 110|year = 2005|url = http://www.phys.huji.ac.il/~shaviv/articles/sensitivity.pdf|doi = 10.1029/2004JA010866|access-date = 17 June 2011|author = Shaviv, Nir J|issue = A08105|pages = A08105|bibcode = 2005JGRA..110.8105S|arxiv = physics/0409123|s2cid = 16364672}}</ref><ref name="Svensmark2007">{{Cite journal |title = Cosmoclimatology: a new theory emerges|journal = Astronomy & Geophysics|volume = 48|year = 2007|pages = 1.18–1.24|doi = 10.1111/j.1468-4004.2007.48118.x|author = Svensmark, Henrik|issue = 1|bibcode = 2007A&G....48a..18S|doi-access = free}}</ref><ref name="Svensmark1998">{{Cite journal |first = Henrik|last = Svensmark|author-link = Henrik Svensmark|title = Influence of Cosmic Rays on Earth's Climate|journal = [[Physical Review Letters]]|year = 1998|volume = 81|issue = 22|pages = 5027–5030|url = http://www.cosis.net/abstracts/COSPAR02/00975/COSPAR02-A-00975.pdf|doi = 10.1103/PhysRevLett.81.5027|access-date = 17 June 2011|bibcode = 1998PhRvL..81.5027S|citeseerx = 10.1.1.522.585}}</ref><ref>{{Cite journal |title = Celestial driver of Phanerozoic climate?|journal = Geological Society of America|volume = 13|year = 2003|page = 4|doi = 10.1130/1052-5173(2003)013<0004:CDOPC>2.0.CO;2|author1=Shaviv, Nir J  |author2=Veizer, Ján |name-list-style=amp |issue = 7|doi-access = free| bibcode=2003GSAT...13g...4S }}</ref> but this hypothesis was not confirmed.<ref>{{Cite journal |author1 = Sun, B.|author2 = Bradley, R.|title = Solar influences on cosmic rays and cloud formation: A reassessment|journal = Journal of Geophysical Research|volume = 107|issue = D14|page = 4211|year = 2002|doi=10.1029/2001jd000560|bibcode = 2002JGRD..107.4211S |doi-access = free}}</ref>
Later papers showed that production of clouds via cosmic rays could not be explained by nucleation particles. Accelerator results failed to produce sufficient, and sufficiently large, particles to result in cloud formation;<ref>{{Cite journal |author1 = Pierce, J.|author2 = Adams, P.|title = Can cosmic rays affect cloud condensation nuclei by altering new particle formation rates?|journal = Geophysical Research Letters|volume = 36|issue = 9|page = 36|year = 2009|doi=10.1029/2009gl037946|bibcode = 2009GeoRL..36.9820P |s2cid = 15704833|doi-access = free}}</ref><ref>{{Cite journal |author = Snow-Kropla, E.|display-authors = etal|title = Cosmic rays, aerosol formation and cloud-condensation nuclei: sensitivities to model uncertainties|journal = Atmospheric Chemistry and Physics|volume = 11|issue = 8|date = Apr 2011|page = 4001|doi=10.5194/acp-11-4001-2011|bibcode = 2011ACP....11.4001S |doi-access = free}}</ref> this includes observations after a major solar storm.<ref name="Erlykin, A., et al. 137">{{Cite journal |author = Erlykin, A.|display-authors = etal|title = A review of the relevance of the 'CLOUD' results and other recent observations to the possible effect of cosmic rays on the terrestrial climate|journal = Meteorology and Atmospheric Physics|volume = 121|issue = 3|page = 137|date = Aug 2013|doi=10.1007/s00703-013-0260-x|arxiv = 1308.5067 |bibcode = 2013MAP...121..137E |s2cid = 118515392}}</ref> Observations after [[Chernobyl disaster|Chernobyl]] do not show any induced clouds.<ref>{{Cite conference |author1 = Sloan, T.|author2 = Wolfendale, A.|author-link2=Arnold Wolfendale|title = Cosmic Rays and Global Warming|book-title = 30TH INTERNATIONAL COSMIC RAY CONFERENCE, Merida, Mexico|date = Jun 2007}}</ref>