According to Nicola Scafetta, a scientist at Duke university climatic changes as from the year 1950 have been a result of predictable, cyclical, and natural occurrences that takes place on the earth’s with very minimal or no help from human activities. According to Nicola Scafetta, those claiming that climatic change is a result of human activities fail to take into consideration climate modulating effects of solar changes. These effects might include how cosmic rays are influenced by cloud-forming thus reducing sunspot activity. He argues that between 50%-70% of global warming on the 20th century can be associated to increased solar activity (Jarman 101).