The United Arab Emirates’ reported decision to leave OPEC would mark a major break inside the global oil system. OPEC is a group of oil-producing countries that coordinates output to influence oil prices. In simple terms, members agree on how much oil to pump. Lower supply usually supports prices. Higher supply usually pressures prices lower. For the UAE, leaving means more freedom. It can produce more oil without following OPEC quotas. That matters because Abu Dhabi has invested heavily to expand product ...