The world's most powerful policymakers are struggling to alleviate the pain of a slowing global economy with few levers left to pull and growing concern that one of them, negative interest rates, already is creating problems of its own.

In an ideal world, elected officials would pull more of the weight with fiscal programs and structural reforms that would improve growth and allow interest rates to rise.

But over three days of conversation here, the dilemma has become clear: Whether it is the U.S.-China trade war, tightfisted spending in Germany or the drawn-out Brexit, broader government policies are moving in the other direction — driving central bankers to mount further rescue efforts, and likely leading to even more negative yielding debt.