This lesson takes students beyond simply asking whether climate change is happening and explores how and why the climate-change debate has evolved over time. Through a clear historical timeline, students follow the development of climate science from the discovery of the greenhouse effect in 1824, through increasing COâ‚‚ measurements and advances in computer modelling, to the establishment of the IPCC and the growth of international and public debate. Students are encouraged to distinguish between scientific debate and public debate, recognising that increasing scientific confidence does not automatically produce the same level of public agreement. By constructing and evaluating the timeline, students develop chronological understanding, evidence-evaluation skills and the ability to explain why public understanding of climate change has not always developed at the same rate as scientific understanding. The lesson therefore provides an essential bridge between understanding the science of climate change and understanding the wider social, political and economic debate surrounding it.