Editor's Summary
14 September 2006
The warmth of the Sun
Small variations in the Sun's power output, or luminosity, attract attention and controversy because of their possible implications for climate change. The changes arise from dark (sunspot) and bright (faculae) structures on the solar disk during the 11-year sunspot cycle. Since 1978 it has been possible to track these accurately with satellites, showing a variation of 0.07%. Foukal et al. review recent advances in our understanding of solar luminosity change and its effects on the energy balance on Earth. They conclude that solar brightening is unlikely to have had a significant effect on climate change since the seventeenth century. More speculative climate changes related to the Sun's ultraviolet light and magnetized plasma output are not yet ruled out, but are hard to quantify due to the complex interactions involved. The cover shows the structures responsible for the luminosity variations.
Review: Variations in solar luminosity and their effect on the Earth's climate
P. Foukal, C. Fröhlich, H. Spruit and T. M. L. Wigley
doi:10.1038/nature05072
