UNITED NATIONS — Over the last four years, as four million Syrian refugees poured into neighboring countries and slipped inexorably into poverty, António Guterres, the United Nations high commissioner for refugees, said he had pleaded in vain with world leaders to take their plight more seriously.
But suddenly, at the United Nations General Assembly this week, leaders of the world’s most powerful countries want to meet with him, all of them deeply worried about the refugee crisis.
So what has changed? Well, nothing, Mr. Guterres said, “except refugees came to rich countries,” expanding the crisis from nations like Lebanon, Turkey and Jordan to those in Europe.
“That completely changed the picture,” he added. “This year, everyone talks about refugees.”
The rush of migrants into Europe, combined with the Continent’s fear that Islamic State fighters may cross porous borders to carry out attacks, has stirred new urgency among Western leaders to address the war in Syria and push harder for an end to it.
They have been huddling on the sidelines of the General Assembly with their rivals from Russia and Iran. They are stepping up aid. And what was seen as a lost cause a few months ago — a political settlement in Syria — was the centerpiece of a lunch hosted by Secretary General Ban Ki-moon this week for the foreign ministers of the five permanent members of the Security Council.
“I have personally the impression we are waking up to this now because this refugee problem is more visible today to Western eyes,” Federica Mogherini, the European Union foreign minister, told reporters this week after a meeting with her counterparts from the region. She said she hoped “this new sense of urgency” could spur creative ideas toward a political settlement.
“I see possible common ground to common diplomatic efforts to bring an end to this war,” she said.
On Tuesday night, the German foreign minister corralled his counterparts from some of the world’s richest countries — the Group of 7 — to pledge aid for Syrian refugees, drumming up $1.8 billion to help the United Nations and the countries still sheltering the bulk of the refugees: Turkey, Lebanon and Jordan.
But the numbers of migrants heading to Europe are growing quickly. More than 500,000 refugees and migrants have crossed the Mediterranean Sea to reach the Continent this year alone, according to the International Organization for Migration.
On Wednesday, the secretary general, Mr. Ban, held a session on the sidelines of the General Assembly devoted to tackling the refugee crisis.
Mr. Ban called on countries to “significantly boost” the number of refugees that they accept and create safe, legal channels for refugees and labor migration, something Europe significantly lacks. He also signaled that the exodus could grow, as people escape areas “ravaged by climate change.”
In a sign of the anxiety, the standard for what amounts to a political solution in Syria seems to be shifting, too. Some officials who had only recently called for the immediate ouster of the Syrian president, Bashar al-Assad, have been softening their language on when he should leave.
France, which backed the idea of airstrikes against the Syrian government after accusing it of conducting chemical weapons attacks two years ago, is now carrying out airstrikes against Mr. Assad’s enemies on the battlefield, hitting Islamic State forces. The French foreign minister, Laurent Fabius, said Wednesday that France was open to the military operations of Mr. Assad’s main ally, Russia, so long as Mr. Assad’s air force stopped using barrel bombs and he was willing to agree to a political transition.
Secretary of State John Kerry echoed the need for political talks on Syria, saying at the Security Council on Wednesday that Mr. Assad would have to “decline to be part of its long-term future.”
Even on the question of Mr. Assad’s departure, there has been a discernible shift. Western diplomats on the Security Council are saying that Mr. Assad would not have to step down right away, but rather at the end of a political transition process. They are also taking pains to say that, having learned from the experience of Iraq, they are keen to avoid a wholesale purge of his government, preferring to sideline “tens, not hundreds,” of his associates, as one Security Council diplomat put it, to maintain stability.
Another Council diplomat said that dismantling Mr. Assad’s army would be far too risky in the face of the threat posed by the Islamic State.
The refugee crisis has become such a central element in the political calculus that it has been used as a rhetorical mortar to lob at rivals.
When the Russian president, Vladimir V. Putin, called on his Western rivals this week to join his country and the Syrian government to defeat the Islamic State, he clearly poked at European concerns, saying, “Then, dear friends, there would be no need for new refugee camps.”
The Saudi foreign minister, Adel al-Jubeir, suggested this week that the Obama administration could have done more to prevent the exodus of Syrians.
“The refugee crisis we see now is a product of not enough robust action to bring about change in Syria over four years and this is a direct consequence of it,” he said.
Mr. Kerry said Wednesday that everyone needed to act quickly to resolve the conflict “understanding fully how urgent this is in the context of refugees flowing out, the impact on Europe, the impact on the region.”
The impact has been felt on both sides of the Atlantic. Last week, theEuropean Union forced through a plan, over the bitter objections of some of its nations, to distribute 120,000 asylum seekers among member states. Only days before, Mr. Kerry announced that the United States would increase the number of refugees it accepts from around the world each year to 100,000, up from the current annual cap of 70,000.
“This topic is a dominant topic indeed,” the German foreign minister, Frank-Walter Steinmeier, said Tuesday evening in announcing the aid pledges from 17 countries, including the Group of 7.
“Sometimes you have to address the most pressing issues and priorities,” he said. “Of course, change will only be possible if we succeed in stabilizing Syria, if we succeed in defusing the war situation.”
Mr. Guterres, the United Nations refugee chief, has asked for just over $4 billion this year to deal with the refugee crisis in Syria, of which only 40 percent has come in.
But he has other refugees to help, too. Indeed, he has many millions of refugees to help. The number of people displaced around the world is at an all-time high since World War II.
But Europe is only a fraction of his troubles. To aid refugees fleeing the Central African Republic, for instance, he has to dip into a pot of United Nations money not earmarked for specific crises. Those refugees are far away from Europe. They do not possibly harbor terrorists who can kill Europeans. They do not get the world powers exercised.
“You can’t imagine how underfunded things are in Africa,” he said.