<div>Professor Philip Stier unpicks the big unknowns of clouds, aerosols and climate change. <br>
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[Photo (C) Shutterstock]</div>

Professor Philip Stier unpicks the big unknowns of clouds, aerosols and climate change. [Photo (C) Shutterstock]

Professor Philip Stier unpicks the big unknowns of clouds, aerosols and climate change.&nbsp;<br>
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[Photo (C) Shutterstock]

Philip Stier on the big unknowns - #TruePlanet series

<p>Audio from the University of Oxford</p>

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