(CNN) The images from Aleppo, Idlib and Syria's border with Turkey can be described in one word: despair.

Tens of thousands of people have fled the relentless bombing and shelling that has paved the way for dramatic battlefield gains by the regime of President Bashar al-Assad and its allies. Hundreds of thousands more remain trapped, awaiting their fate with trepidation.

In the space of a few weeks, the Syrian battlefield has been transformed, the balance of forces pulverized and the prospects for peace talks -- already dark -- virtually extinguished. Another tide of displaced civilians converge on the Turkish border, trapped by the advance of regime forces.

Refugees arrive near the Turkish border as they flee the city of Aleppo on February 6.

Refugees arrive near the Turkish border as they flee the city of Aleppo on February 6.

A child tries to climb over a fence near the Turkish border as Syrians fleeing the northern city of Aleppo wait on February 6.

A child tries to climb over a fence near the Turkish border as Syrians fleeing the northern city of Aleppo wait on February 6.

Refugees brave the cold and rain as they arrive at the Turkish border on February 6.

Refugees brave the cold and rain as they arrive at the Turkish border on February 6.

Syrian refugees are pictured in a camp as they flee the city of Aleppo on February 6.

Syrian refugees are pictured in a camp as they flee the city of Aleppo on February 6.

Refugees push each other as they wait for tents near the Turkish border on February 6.

Refugees push each other as they wait for tents near the Turkish border on February 6.

Syrian refugees await their fate near the Turkish border gate as they flee the northern embattled city of Aleppo on February 6, 2016.

Syrian refugees await their fate near the Turkish border gate as they flee the northern embattled city of Aleppo on February 6, 2016.

Last week, the regime of Bashar al-Assad, supported by Iranian and Lebanese Shia militia, severed the main road from Aleppo to the Turkish border, a narrow corridor through which the rebels and NGOs alike moved supplies. The Syrian Observatory for Human Rights reports that several villages in the area were hit by airstrikes on Sunday.

A defining battle for Aleppo, Syria's largest city before the war, seems imminent. Regime forces and their allies on the ground, supported by Russian bombers in the air, are tightening the noose around the eastern half of the city, still held by a coalition of rebel groups. It's estimated some 320,000 people still live, or subsist, there -- under continual bombardment.

Shortages of diesel and food are reported, but many people simply don't dare or can't afford to leave. One civil defense worker told the Guardian newspaper: "They think, 'We can die in our own homes, we don't need to go to other places to die.' "

Russian revolution

Beyond the humanitarian catastrophe that looms, the plight of Aleppo symbolizes the rapid transformation of the Syrian battlefield since the regime, Iran and Russia came together. For much of 2015, Assad's forces were on the defensive, as rebel groups consolidated and took major towns in Idlib, the Aleppo countryside and began to attack regime strongholds in Latakia.

It was the very real possibility of regime collapse that prompted Russian intervention in September. Russian airstrikes and Iranian militia have since bolstered regime troops and reversed the tide. Aleppo is their most prized target.

"Should the rebel-held parts of the city ultimately fall, it will be a dramatic victory for Assad and the greatest setback to the rebellion since the start of the uprising in 2011," says Emile Hokayem in Foreign Policy

The Institute for the Study of War says a successful regime offensive around Aleppo would "shatter opposition morale, fundamentally challenge Turkish strategic ambitions and deny the opposition its most valuable bargaining chip before the international community."

Rebel groups have made desperate appeals for help in defending the city.

The notoriously fractious resistance groups are declaring alliances to bolster their collective resistance. One of the most important groups, Ahrar al Sham, announced at the weekend: "We extend our hands to all factions of the Syrian revolution ... and we announce our acceptance for unity with them without any prerequisites."

But even briefly united, they can't shoot down planes, and they don't have T-90 tanks.

Since Russia began its air campaign, most of its strikes have been on cities and towns held by the rebels in western Syria. The aim: to link regime-held territory from the capital to the coast. These are not areas where ISIS has much of a presence; al Nusra, Ahrar al Sham and elements of the Free Syrian Army are the main groups.

Resistance has been fierce, but the sheer scale of the assault has gradually pried one town after another -- or rather their ruins -- from rebel hands.

Photos: Inside Syria: Roadtrip across a war-torn nation Officials say more than 70% of the buildings in the Syrian city of Kobani have been damaged or destroyed. Kurdish officials say they've already removed 1.6 million tons of rubble. Hide Caption 1 of 16 Photos: Inside Syria: Roadtrip across a war-torn nation The Muhajar brothers -- Yusif, 3, Mustafa, 8, and Ali, 11 -- in front of their partially destroyed house in Kobani. As someone pointed out to CNN's Ben Wedeman, the expressions from youngest to oldest go from smiling to frowning. Hide Caption 2 of 16 Photos: Inside Syria: Roadtrip across a war-torn nation A young resident of Al-Houl, whose extended family of 40 is hoping to return home. They're staying in other abandoned homes a few kilometers away. Kurdish officials say most of the residents of Al-Houl fled with ISIS. Hide Caption 3 of 16 Photos: Inside Syria: Roadtrip across a war-torn nation More Kobani ruins. They go on block after block after block. Hide Caption 4 of 16 Photos: Inside Syria: Roadtrip across a war-torn nation Two members of the YPK, the Kurdish "Women's Defence Units," on the front lines south of Al-Houl, in Al-Hassakeh province. Hide Caption 5 of 16 Photos: Inside Syria: Roadtrip across a war-torn nation A sign left by ISIS on the main street in Al-Houl urging -- or perhaps better, ordering -- women to be completely veiled. Hide Caption 6 of 16 Photos: Inside Syria: Roadtrip across a war-torn nation A young resident of Kobani. She stood by her father, Mustafa Ismail, who watched silently for hours as a bulldozer hauled away the remains of his three-story house. Hide Caption 7 of 16 Photos: Inside Syria: Roadtrip across a war-torn nation Mustafa Ismail, a construction worker, tells CNN's Ben Wedeman: "I worked thirty years to build this house, and it was destroyed in a matter of seconds. What can we do? We have to rebuild." Hide Caption 8 of 16 Photos: Inside Syria: Roadtrip across a war-torn nation 17-year-old Hamouda is a Kobani resident whose hobby is raising pigeons -- a pastime banned by ISIS because it's a waste of time. He fled with his family to Turkey across the border during the five-month battle for Kobani. Hide Caption 9 of 16 Photos: Inside Syria: Roadtrip across a war-torn nation The view from Hammouda's pigeon perch. The reconstruction effort in Kobani has come to a screeching halt after Turkey closed its border, depriving the town of the building materials it desperately needs. Hide Caption 10 of 16 Photos: Inside Syria: Roadtrip across a war-torn nation These children stopped playing on top of the ruins of a school to pose for this photo. They thought the CNN crew were funny. They laughed. Hide Caption 11 of 16 Photos: Inside Syria: Roadtrip across a war-torn nation Despite the destruction, Kobani residents are trying revive their town. Businesses are reopening and people are returning to what's left of their homes. Hide Caption 12 of 16 Photos: Inside Syria: Roadtrip across a war-torn nation Ali Mattar, a farmer, wants to return to his home in Al-Houl and resume a normal life. "I can't understand why we aren't allowed home," he said. A Kurdish official assured him as soon as the town is cleared of mines and booby traps, he will be able to do so. Hide Caption 13 of 16 Photos: Inside Syria: Roadtrip across a war-torn nation ISIS' courthouse in Al-Houl, previously a school. The building also housed offices for an ISIS charity, with empty boxes marked "shoes" sent from an Islamic charity in Durban, South Africa. Hide Caption 14 of 16 Photos: Inside Syria: Roadtrip across a war-torn nation Ben Wedeman interviewing an Armenian store owner in Al-Qamishli, one of the last cities in Syria to have been spared widespread death, destruction, and the sting of sectarian strife. He employs a Muslim Arab refugee from Dair Al-Zour who fled ISIS, which controls most of that city. Hide Caption 15 of 16 Photos: Inside Syria: Roadtrip across a war-torn nation Lewand Rojava, a 35-year old commander of the Kurdish YPG, the Peoples' Defense Units -- arguably the most effective fighting force in the war on ISIS in Syria. Hide Caption 16 of 16

In the process, senior rebel commanders have been killed in Homs, Idlib and Aleppo provinces.

Some commentators believe that the Assad regime and Russia set out to hoodwink the West by agreeing to the Geneva peace process while stepping up their military campaign, to create "facts on the ground" that would vastly change the balance in the negotiations.

"Their ultimate objective is to force the world to make an unconscionable choice between Assad and ISIS," says Hokayem. For now, ISIS is waiting out the battle for Aleppo and watching its rivals get pummeled. It is crowing that it is the only real defender of Sunni Muslims against the Shia-dominated forces now on the offensive.

The Syrian Kurds, whose attitude toward the Assad regime might be described as ambivalent, also appear to be taking advantage of the situation, chipping away at rebel-held villages north of Aleppo. According to diplomats in the region, they are being encouraged by Russia -- keen to antagonize Turkey at any opportunity.

For Aleppo, read Grozny

Some analysts compare Russian President Vladimir Putin's strategy in Syria with the Russian campaign in Chechnya in 1999, which he directed as Prime Minister. All opposition figures were marked as terrorists, and Russian forces destroyed cities such as Grozny in which insurgents lived, as well as the insurgents themselves. By some estimates, 80% of Grozny was rendered uninhabitable. Human Rights Watch published a report on the Chechen campaign in 2000 entitled "Welcome to Hell" and accusing Russian forces of egregious human rights violations.

Putin pursued an exclusively military solution against the Chechen insurgency, and ultimately it worked. It took six years and an unknown number of Russian military casualties, but today acts of resistance in Chechnya are few and far between, and the republic is run by a Putin loyalist.

The same approach is apparent in Syria. After his meeting with Putin at the United Nations in September, U.S. President Barack Obama said of the Russians' view of the rebels: "From their perspective, they're all terrorists."

But Chechnya is not the only precedent.

Jihadists, some of them from the Caucasus, have threatened to turn Syria into another Afghanistan for the Russians. While they may be driven from territory they hold, they are unlikely to be driven from Syria and could revert to insurgency tactics such as ambushes, assassinations and suicide bombings.

To some analysts, the regime advance will only radicalize what remains of rebel forces in Syria. Hokayem speaks of a "widespread and understandable feeling of betrayal in the rebellion, whose U.S.-friendly elements are increasingly losing face within opposition circles."

Last month, Osama Abu Zeid, a senior adviser to the moderate Free Syrian Army, complained that "the U.S. is gradually moving from a neutral position toward being a partner in crime as it allows Assad and his allies to kill Syrians."

Several rebel groups, as well as Turkish officials, blame Washington for the failure to establish a "safe-haven" inside Syria last year. Some in Washington take the same view.

In an Op-Ed for The Washington Post , two former senior officials, Nicholas Burns and James Jeffries, urge the Obama administration to "dramatically expand funding for the moderate Sunni and Kurdish forces that pose an alternative to Assad's government and the Islamic State" and "reconsider what it has rejected in the past: the creation of a safe zone in northern Syria to protect civilians, along with a no-fly zone to enforce it."

But they acknowledge that "defending the zone, preventing it from being overwhelmed by refugees, grounding it in a convincing legal justification and keeping out jihadist groups would be daunting tasks."

Europe's next nightmare

The United Nations estimated Friday that 40,000 people have already been displaced by the fighting in Aleppo . But the current exodus is by no means the first since the Russian air campaign began. In just three weeks in October, the United Nations reported the displacement of 120,000 people from Aleppo, Hama and Idlib. Nor will it be the last.

Photos: Blueprints of war: Syrian artists paint the struggle Photos: Blueprints of war: Syrian artists paint the struggle The posters by Fares Cachoux are simple and haunting. Though he was living abroad as the civil war broke out in his homeland, he wanted to show the world the stories coming out of Syria. His most recent poster reflects on what the International Organization for Migration says were nearly 1 million refugees who have attempted to cross the Mediterranean in 2015 for safer land. Half of these people are Syrian. "The sea graveyard for countless Syrians attempting to cross to escape DEATH. ... She awaits in the depths of the waves of the Mediterranean," the caption reads in French below the work he sent to CNN. Hide Caption 1 of 10 Photos: Blueprints of war: Syrian artists paint the struggle Cartoonist Hossam Alsaadi ran a coffee shop used as a haven by young Syrians who opposed their nation's regime at the start of the civil war. Now, those coffee shops are few and far between. The United Nations estimates more than 400,000 people in dozens of villages are under siege, many of them having to live off salt, water and grass to survive. Aid deliveries have become rare for those who cannot join the 11 million people who have had to abandon their homes. Hide Caption 2 of 10 Photos: Blueprints of war: Syrian artists paint the struggle Syrian artist Sedki Al Imam fled his hometown of Aleppo in 2012, eventually finding a home with his wife in Uppsala, Sweden. "It's heartbreaking," he says of the fighting between Syrian regime forces and rebel groups near Aleppo this week as peace talks were put on hold. The death toll rises as rockets, bombs and airstrikes pound already-beleaguered cities. Hide Caption 3 of 10 Photos: Blueprints of war: Syrian artists paint the struggle An anonymous anti-war artist whose Facebook handle is DAALI has a series of works captioned, "If it's not happening in your country that doesn't mean it's not happening." Many of them reference scenes of oppression in from Syria transferred to a Western event or location. In this case, women wearing niqabs and gloves -- clothing forced onto them in ISIS-controlled areas -- march on a fashion runway. An ISIS flag hangs in the back. Since the emergence of the Islamic State in Iraq and Syria, reports of rape, slavery and extreme oppression have filtered out of the group's tightly controlled territory. ISIS also claims more than 100 female foreign recruits, the majority of them from Europe. Hide Caption 4 of 10 Photos: Blueprints of war: Syrian artists paint the struggle The war has destroyed Aleppo, like other parts of Syria, artist Jawad says. It's now divided, with rebels controlling one side and the government the other. Barrel bombs pound the streets of a city that was once the most populated of the country. An estimated 300,000 civilians remain in rebel-held areas alone. Jawad says of this image: "Aleppo Citadel as I saw it in the midst of one of my nightmares. A once stunning, historical world-renowned structure is now sitting among utter destruction." Hide Caption 5 of 10 Photos: Blueprints of war: Syrian artists paint the struggle Raised in the Alawite stronghold of Latakia, Wajdi Saleh also spent time in Aleppo, where he traces his roots and went to university. Forced to flee to Turkey a few years ago, he still wants to focus on the effect of Syria's civil war on the people who have not left and cannot leave. Referring to the rebel-held town of Douma, he paints its name in blood, in Arabic, on a wall. The date refers to August 16, 2015, when more than 80 people were killed during multiple airstrikes by the regime. An activist told CNN at the time: "Dead human bodies were just left on the sidewalk." Hide Caption 6 of 10 Photos: Blueprints of war: Syrian artists paint the struggle Designer Saif Aldeen Tahhan is one of the thousands of refugees who made a treacherous journey across the Mediterranean Sea to get to Europe. Now, safely in Denmark, he designs pieces about the situation at home in Syria, one of them reflecting on the recent news out of Madaya. The rebel-held Syrian town's plight grabbed the attention of the world early this year as images of starving children, women cooking grass, and emaciated residents populated news feeds from smuggled videos put out by activists. Aid deliveries were finally allowed into the town mid-January, but people are still starving. Hide Caption 7 of 10 Photos: Blueprints of war: Syrian artists paint the struggle Sedki Al Imam in his own words: "As different media outlets have always portrayed a good and an evil side in the ongoing Syrian crisis, 'Kingdom of Hyenas' aims to draw a truer picture of the Syrian war. It depicts all fighting factions as monstrous creatures, mercilessly killing innocents, and stealing everything they lay their hands on. It also most importantly compares Syria to a jungle, where justice, morality, and dignity are unheard-of, and the powerful feed off the blood of the weak." Hide Caption 8 of 10 Photos: Blueprints of war: Syrian artists paint the struggle Artist Jawad no longer lives in Syria, though he says he is "Syrian by kismet," having lived through the rise of President Bashar Al-Assad's rule prior to the demonstrations and subsequent civil war's beginning, in 2011. Like the majority of Syria, Syria's conscripted army was mostly Sunni Muslim. At the start of the war, opposition groups accused the regime of killing more than 1,300 Syrians in first three months of the war. The "military boot has become a despicable national icon in Syria," Jawad says. "It squeezes and steps on our last surviving blood orange, the Syrian people," he adds. Hide Caption 9 of 10 Photos: Blueprints of war: Syrian artists paint the struggle Anti-war anonymous artist DAALI focuses his work on Syria so the world does not ignore it just "because it is not happening in their countries, because the dead people are not their families, because the destroyed houses are not theirs, because the women raped are not their wives, simply because they are just not living there." More than 4.5 million Syrians have left their homes, the majority of them having fled to neighboring countries. Many live in tents or container homes with no running water and seldom access to electricity -- in stark contrast to their lives at home. Few have the chance to move into the cities and continue their lives. Hide Caption 10 of 10

Turkey -- which already has 2.5 million Syrian refugees on its soil -- says it is close to capacity. The European Union is pouring cash ($3.3 billion) into a vastly expanded program to house refugees in Turkey, Jordan and Lebanon, trying to forestall another surge of refugees across the Mediterranean. But it may not be enough.

Some EU officials see Europe's expensive and divisive refugee crisis as an intended consequence of Russian policy.

"Putin likes to cast himself as a man of order, but his policies have brought more chaos, and Europe is set to pay an increasing price," says Guardian columnist Natalie Nougayrède

A 'painful year'

The main supporters of the rebels in northwest Syria -- Turkey, Saudi Arabia and Qatar -- are now short of options. They could send weapons across the border into Idlib, but the province is largely controlled by al Nusra.

They seem unlikely to walk away from a struggle in which they have invested so heavily and watch their Shia enemies -- Hezbollah, the Alawite-led regime, the Iranian Revolutionary Guard -- claim victory.

Fabrice Balanche at the Washington Institute speculates they may try to "set up a new rebel umbrella group similar to Jaish al-Fatah, and/or send anti-aircraft missiles to certain brigades...(or) open a new front in northern Lebanon."

"The question is, do Riyadh and Ankara have the means and willingness to conduct such a bold, dangerous action?" Balanche asks.

It is hard to find anyone who believes the situation in Syria will get better before it gets much worse.

"The conditions are in place," says Hokayem, "for a disastrous collapse of the Geneva talks -- now delayed until late February -- and a painful, bloody year in Syria."