We have analyzed the record of Earth's global temperature variations between 1850 and 2007 looking for signals of periodic variations and compared our results with solar activity variations in the same time period. Significant periods are found at 9.4, 10.6 and 20.9 years. These periodic variations may be caused by solar activity. However, and amazingly enough, we also find at least 17 other significant periodic variations in addition to expected variations with periods of 1 year and of half a year. The result is considered in terms of solar related forcing mechanisms. These may be variable solar heating associated with the small changes in solar irradiance over the solar cycle, or direct effects of interactions between variable magnetic fields carried by the solar wind and particles and fields in interplanetary space or in the Earth's ionosphere.