Finding the missing sunlight

Global climate change is one of the most important scientific issues facing mankind today. But there is a major discrepancy between the sunlight reaching the Earth's surface and that predicted by current physical models. There are a number of potential causes, many involving water vapour, but the mechanisms are poorly understood because of the limited measurements made to date. NPL Senior Researcher Tom Gardiner describes NPL's strategic research project with Reading University scientists that is helping to throw new light on the subject. Recording Crown Copyright 2006. Reproduced by permission of the Controller of HMSO and Queen's Printer for Scotland.