A war with Iran could cost $3 trillion.

According to a report from the Federation of American Scientists, a U.S. war against Iran could cost the global economy as much as $3 trillion.

The group based its estimates on a series of escalating steps, from sanctions to a blockade to targeted air strikes to a more comprehensive aerial bombing campaign culminating in a ground invasion to destroy Iran's nuclear facilities and military bases. Each step gets its own estimated price tag: additional sanctions are expected to cost the world $64 billion while a blockade would cost an estimated $325 billion. More aggressive steps cost into the trillions.

Will these costs stay the hands of policy makers in the U.S. and Israel and Europe?