Our knowledge of the Sunís radiative output will be discussed in the context of the rapid increase in global temperature in the Earthís atmosphere in the last fifty years. History of programs to measure the Sunís Radiative Output in the last three solar cycles will be reviewed. These programs give the first continuous record of solar irradiance variability fundamental to our understanding solar forcing in both contemporary and past climate change. Properties of time series of Total Solar Irradiance, Spectral Irradiances, Solar Variability Indices will be compared to that for the Earthís global temperature. Although solar activity measured by the sunspot number trends upward from the beginning of the 19th century, it does not follow the rapid increase in terrestrial temperature since 1960.