WASHINGTON — The head of the International Monetary Fund sketched a dim outlook for the global economy and said all countries must work together to resolve Europe’s escalating debt crisis. IMF Managing Director Christine Lagarde said Europe’s problems will not be solved by Europe alone. “It’s not a crisis that will be resolved by one group of countries taking action,” Lagarde said in remarks at a State Department conference. “It’s going to be hopefully resolved by all countries, all regions, all categories of countries actually taking action.” She said if the issues are not dealt with decisively, the global economy could confront the same threats that pushed the world into the Great Depression of the 1930s. “It’s a question of actually facing the issues, not being in denial, accepting the truth, accepting the reality, then dealing with it,” Lagarde said. She did not provide details on what actions she expected individual countries or the IMF to take. She also cautioned financial markets to allow time for individual nations to work through the political process to arrive at a solution. “It would be ideal and it would be lovely from a market perspective if it was not just currently but immediately signed, sealed and delivered, done deal, overnight,” she said. “Unfortunately, for those of you who have the privilege of belonging to democracies, things do not happen in that way and things do take time and have to go through parliamentary processes.” Last week, a number of European countries said their central banks would make loans to the IMF to bolster IMF resources. After the announcement, the Obama administration said it would not provide more support to the IMF because it said the agency had sufficient resources.