The fund faces the prospect of a major European country being shut out of the global debt markets, an event that might ignite a second global recession. It also faces the possibility of developing countries seeking its aid when its resources have been deployed in Europe.

“Circumstances have changed,” said Eswar S. Prasad, a professor of trade policy at Cornell University and a former I.M.F. economist. “It is becoming clear that Europe is in deep trouble. The second and more important aspect is that there continues to be increasing pressure on other countries, especially emerging-market countries. There has been a flight to safety.”

Bond yields have risen for countries like Brazil, Turkey and India, with investors preferring the safety of the dollar or yen. And capital flows have reversed. According to the World Bank, investors poured $309 billion into developing countries in the second half of 2010. By the second half of 2011, that number had shrunk to $170 billion.

“That makes developing economies very vulnerable,” Professor Prasad said, adding that in normal economic times such countries would be “just fine.”

Additional financing might bolster the fund’s ability to aid Europe, though even with $1 trillion in available financing, it would not have the resources to help big countries like Italy or Spain. Therefore, during the executive board meetings, the fund urged Europe to double its own firewall. The participant in the meetings said that the fund identified needs for about $2 trillion in global financing, and said about three-quarters of the need was in Europe. Non-European members insisted that Europeans take the lead in providing money for Europe, the participant said.

But the additional financing would significantly bolster the monetary fund’s ability to help smaller countries and the “innocent bystanders” that might be hurt by the euro zone crisis.

The markets cheered the fund’s announcement. The euro climbed in value against the dollar, and stocks rose in New York and London.