http://news.bbc.co.uk/2/hi/science/nature/7327393.stm

Segnalo quest'articolo perchè l'attività del sole o dei raggi cosmici è stata spesso (e anche in anni recenti) presa come spiegazione alternativa al GW indotto da emissioni di gas serra.

Partendo da quest'ipotesi, in Inghilterra hanno tentato di verificare se, negli ultimi 20 anni vi sia stato un nesso tra (oggettivo) riscaldamento e (eventuale) attività solare.
Conclusione: no.

Qui l'abstract:

http://www.iop.org/EJ/abstract/1748-9326/3/2/024001

Abstract. A decrease in the globally averaged low level cloud cover, deduced from the ISCCP infrared data, as the cosmic ray intensity decreased during the solar cycle 22 was observed by two groups. The groups went on to hypothesize that the decrease in ionization due to cosmic rays causes the decrease in cloud cover, thereby explaining a large part of the currently observed global warming. We have examined this hypothesis to look for evidence to corroborate it. None has been found and so our conclusions are to doubt it. From the absence of corroborative evidence, we estimate that less than 23%, at the 95% confidence level, of the 11 year cycle change in the globally averaged cloud cover observed in solar cycle 22 is due to the change in the rate of ionization from the solar modulation of cosmic rays.

qui l'articolo (e non ho avuto ancora tempo di leggerlo)

http://www.iop.org/EJ/article/1748-9...4-6fba39c153ef