Brent crude is up almost 3.5% to $58.20 per barrel this morning after Saudi Arabia started bombing targets in neighbouring Yemen. Yemen contributes less than 0.2% of global oil supply but it is located on Bab el-Mandeb, the fourth-biggest shipping choke point in the world through which around 3.5 million barrels a day of oil and petroleum passes.
Closing the strait would stop tankers from the Persian Gulf from reaching the Suez Canal, diverting them around the southern tip of Africa, adding to transit time and cost. If this worst case scenario did happen the impact would most clearly be felt on the oil market, but the route is a major transit route for the worlds container traffic and so any disruption would also be a drag on world trade and economic growth.