SFU Faculty of Science: Global Warming Seminar Series "The CLOUD Experiment at CERN"

Abstract

Understanding the causes of climate change is one of the most important challenges facing science today. The Intergovernmental Panel on Climate Change attributes more than 90% of the observed warming during the last century to anthropogenic causes, especially the increase in atmospheric carbon dioxide from fossil fuels. However, during the last ten thousand years since the end of the last ice age, and prior to industrialisation, the climate has frequently changed on 100-year time scales by amounts comparable to the current warming. At present there is no established mechanism to explain these natural climate changes, but associations are frequently found with solar variability, which is recorded in archives that measure past variations of cosmic ray intensity. This raises the intriguing question of whether cosmic rays may directly affect the climate. This talk presents an overview of the palaeoclimatic evidence for solar/cosmic ray forcing of the climate, and the initial results from the CLOUD experiment at CERN which is investigating and quantifying the physical mechanisms that may link cosmic rays with aerosols, clouds and climate.