The role of the changes in the sun’s output in overall global climate change has not been particularly well understood. There is an 11 year solar cycle when the activity of the sun goes up and down, and scientists have been investigating what kind of influence these changes have on the Earth’s climate relative to the relative concentration of greenhouse gases. One of the most enduring climate change myths is that it is the sun that is causing global warming/. The argument is only sustained by being selective with the data chosen highlighting periods when the sun and climate changes are in some synchrony and ignoring recent data where they diverge. 

The changes in solar irradiance have only been measured with some accuracy by satellites for around 30 years, this very precise data show changes only of a few tenths of a percent depending on the level of solar activity over the 11 year cycle. Changes over longer periods have to be estimated from other sources which are important for building climate models. It is known that one component of recent global climate change was contributed by the increased solar activity of the last solar cycle; this was only a small part when compared with the impact of the additional greenhouse gases over the last period. In fact, over the last 39 years of overall global rise in temperature, the sun has shown a cooling trend and thus the sun’s activity and global warming are going in entirely opposite directions. Groups of scientists have independently concluded that the sun therefore cannot be the cause of recent global warming as the effects of global climate change are apparent regardless of the data showing that the sun is again less bright during a period of minimum solar activity.