How clouds affect the Earth's temperature
Accurate climate modelling has been elusive for scientists and the failure has been a stick wielded with glee by climate change denialists. (We discuss some of the issues around understanding climate sensitivity in this week's Climatewatch, here.)
This Ted-Ed video explains one of the reasons why it has been so hard to translate the increase in carbon dioxide in the atmosphere to an accurate estimate of how much temperatures will rise.
British experimental particle physicist Jasper Kirkby says it's all down to a lack of understanding of aerosols and clouds. He explains an ambitious experiment at CERN that aims to improve our knowledge that should lead to a better understanding of climate sensitivity.
You can get more information about Kirkby's full lesson here.