When the world's economies are on a fixed gold standard and the discoveries of gold do not keep pace with the growing world GDP, what happens?

When the world's economies are on a fixed gold standard and the discoveries of gold do not keep pace with the growing world GDP, what happens?

If world’s economies are on gold standard and the gold production does not keep with growingworld economies, even the money supply growth declines. As money supply also grows at avery reduced...