As G20 leaders meet this week, fluctuating currencies will be at the center of a lot of discussions. World Bank president Robert Zoellick suggests that they consider some sort of updated gold standard . While that proposal seems unlikely to get serious consideration, Slate 's Christopher Beam "entertain(s) the possibility," in order to explain just what Zoellick's modest proposal would mean. First, the government would have to decide what the price of gold is. That's a lot harder than it sounds. In theory, there's an ideal rate at which to peg currency against gold. We just don't know what it is. Gold is notoriously volatile-its price has doubled over the last two years. If the Federal Reserve were to simply fix the dollar to the price of gold on a given day, and demand for gold changed drastically, it would wreak havoc on the economy. If the Fed pegs the rate too high, for example, people would want to trade their dollars for gold, forcing the Fed to raise interest rates in order to make dollars more attractive. Even if the Fed were to pick the rate correctly, it would still have to make adjustments based on the economies of the United States' trading partners. If the dollar is growing in value, but another country's currency is decreasing in value, yet both currencies are pegged to gold, something has to give-either one of the currencies has to inflate or deflate, or the exchange rate has to be adjusted. Once the Fed set the price of gold, it would then have to keep the currency fixed, leaving the economy subject to the vicissitudes of the gold index. If the price of gold goes up, the United States would have to raise interest rates, which could lead to tighter credit. Which might be OK, except that gold is a primary indicator of economic uncertainty: When the economy is bad, the price of gold goes up. So the Fed would be tightening credit just when people need it most. The result: a deflationary spiral that drives the economy even deeper into recession. Read Gold Rush here Meanwhile, Harvard Kennedy School Economist Jeff Frankel takes Zoellick's proposal less literally, and briefly explains the core idea of shifting the global monetary system off of being pegged to one currency: the dollar. Read Gold: A Rival for the Dollar here .