Why OPEC is trending

<p>The United Arab Emirates announced on Tuesday that it will leave OPEC, a decades-old cartel of the world’s top oil exporters, at the end of the week. CNN's Hanna Ziady explains how the UAE's shocking decision could affect global oil markets. Discover more videos, including live streams and exclusive storytelling, on our <a href="http://cnn.com/watch">Watch</a> page.</p>