Online courses committee member Geoff Saunders is now well into the second week of ‘Climate Change: The Science’, hosted by the University of British Columbia, and says the science is coming thick and fast. ‘The first week concentrated on the current state of our climate knowledge, particularly the sources and reliability of data concerning the climate. No surprise that our current understanding of climate in relation to CO2 in the atmosphere is good. But you may be surprised to know that we are nowhere near as clear about the interaction of clouds with climate. ‘In week two we moved on to climate systems and the dynamics of that govern the movement of heat between the different elements of the planet, biosphere, hydrosphere, atmosphere and geosphere. The sun is the source of heat input to these systems, and its variability has measurable effects on the earth’s climate. Understanding that variability can help us understand historic climate and ice ages. ‘As the course continues, I expect we will use knowledge of the past and present to make testable predictions about the future – and examine the reliability of those predictions.’