The interactions and effects of aerosols and clouds are among the largest uncertainties in the assessment and modeling of climate change. Due to the large human influence on planet Earth, remote locations that allow to probe pristine air approximating pre-industrial conditions are becoming progressively rare. Such conditions are, however, of particular scientific interest for understanding climate and global environmental change. I will present results from the Amazon Tall Tower Observatory (ATTO), the Barbados Atmospheric Chemistry Observatory (BACO) and on board of the research aircraft HALO to better understand aerosol sources and effects in our current and future climate.