There is a great deal of confusion regarding how long carbon dioxide (CO
2) persists in the atmosphere. There are at least two reasons for this. The first reason is that there are multiple physical and biological processes that combine to remove CO
2 from the air and they behave differently and at different speeds. The second reason is that the Intergovernmental Panel on Climate Change (IPCC) has changed how it describes the lifetime of CO
2 in the Summary for Policymakers twice over the course of four assessment reports. And since most politicians and media don’t dive deeper into the assessment reports than the summaries, some confusion is reasonable, if unfortunate.