another cause of global warming

It is accepted that global warming is imminent. It is said that the main cause of global warming is increase of greenhouse gas, such as CO2,but the course of it is not only greenhouse gas. There are many courses. I heard the course which I have ever heard. Perhaps another course of global warming is that we can't see more sunspot than precious days,that is, the number of sunset maybe increase. If the number of sunset is decreasing, the number of cosmic rays will increase and then, the size of cloud will be big ,and sunbeam will be shuted out, and earth's temperature is down. When I read this article, I was very surprised. What do you think after knowing this course of global warming?