What Does the State of Earth's Whole Atmosphere Tell Us About Climate Change?

The search for effects of solar variability on weather and climate has a long and checkered history. Empirically, the connection is not easy to establish due to the relatively short period for which instrumental climate records are available, the even shorter era of accurate solar brightness measurements from space, and the fact that the effects of solar brightness changes appear to be small compared to other sources of natural climate variability. Understanding the contribution of solar variability to climate variations is important, however, since we need to quantify the Sun's role during times of natural and anthropogenic climate change. The evolution of solar brightness and Earth's surface temperature over the past millennium is of considerable interest in this context since past grand minima of solar activity have long been suspected to cause cooler climatic conditions on Earth. The  most prominent example for this is the connection between the 17th-century Maunder Minimum and the Little Ice Age with markedly lower winter temperatures over Europe. In my presentation, I will review recent reconstructions of past solar irradiance and present new modelling results concerning the cause and extent of the Little Ice Age, discussing in particular the implications for past and future climate change.