German Economy Minister Peter Altmaier will meet this week with U.S. Commerce Secretary Wilbur Ross in an attempt to head off a trade war over recently announced U.S. steel and aluminum tariffs on imports, Bloomberg reported March 18. For all countries except those that have been granted an exemption — such as Canada and Mexico — the tariffs are scheduled to go into effect March 23. Countries around the world have been strategizing over how to respond to them .