Researchers in the US, Switzerland, and Germany have concluded that changes in the Sun's brightness over the past thousand years have had only a minor effect on Earth's climate, according to a paper published in the September 14th Nature. Peter Foukal of Heliophysics, Inc., led the study, which looks at the historical records of sunspot activity over the last century compared to radioisotopes produced in Earth's atmosphere and recorded in the Greenland and Antarctic ice sheets. The study also focused on data from spacecraft radiometers since 1978, concluding that the variations in solar brightness caused by sunspot activity are too small to account for the global warming observed in the past thirty years.

In related climate news, data collected by the NASA Imager for Magnetopause to Aurora Global Exploration (IMAGE) satellite shows that tides of air generated by intense thunderstorm activity over South America, Africa, and Southeast Asia alter the structure of the ionosphere. Published in the August 11th Geophysical Research Letters, the paper claims to be the first to connect the weather on Earth with space weather that occurs high in the ionosphere.