The world was on lockdown for most of 2020. But from the Caucasus to the Horn of Africa to the Himalayas, several conflicts, some frozen for decades, erupted in violence.
Here are the top conflicts or issues that could burst into all-out crises in 2021.
Nuclear arms race: From rogue states to regional tensions
At the start of 2020, the Bulletin of the Atomic Scientists made a dramatic announcement -- its famed Doomsday Clock was the closest to midnight it's ever been, with the threats of nuclear war and climate change growing ever more acute.
"National leaders have ended or undermined several major arms control treaties and negotiations during the last year, creating an environment conducive to a renewed nuclear arms race, to the proliferation of nuclear weapons, and to lowered barriers to nuclear war," the group said in January.
Twelve months later, the last nuclear arms control pact between the U.S. and Russia is weeks from expiry, with no plans to extend it in sight. China continues to develop its nuclear arsenal, possibly even doubling it in the next decade, according to the Pentagon. It's also clashed high in the Himalayas with its nuclear-armed neighbor India, which in turn spilled blood with nuclear-armed rival Pakistan over the disputed territory Kashmir.
As the global infrastructure to constrain nuclear weapons wanes, any one of these could turn into a flashpoint next year, and that's without even mentioning the rogue nuclear power states North Korea and Iran -- both of which are likely to test the incoming Biden administration.
After four years of President Donald Trump's policies, North Korea has more nuclear weapons and enhanced ballistic missile capability, which it may show off with a test launch early in President-elect Joe Biden's term to try to garner some attention and leverage, according to analysts. While the likelihood of a "fire and fury" response will diminish after Trump's departure, the risk of a skirmish spiraling into all-out war remains real, according to analysts.
Iran doesn't have nuclear weapons and says it won't pursue them, but it once again has a stockpile of enriched uranium and a host of spinning centrifuges that decrease its so-called "breakout time" to potentially develop the bomb, according to nuclear experts. Analysts expect its forces, under disguise or through proxies, could resume attacks in the Persian Gulf region to build leverage ahead of possible negotiations with Biden's team, risking conflict with U.S., Israeli, or Arab forces.
Terrorism threat expands, seizing instability across Africa
On the campaign trail, Trump and his senior advisers repeatedly celebrated the defeat of ISIS's so-called caliphate in Iraq and Syria. But since then, the terror threat has dispersed, with fighters and weapons flowing out of shrinking ISIS territory to new pockets around the world.
Across Africa in particular, the world's youngest and fastest-growing continent, ISIS affiliates are now gaining strength, especially in Nigeria, Mozambique and the Congo -- although a few terrorism experts caution some claim to be more powerful than they are in reality.
In the Democratic Republic of Congo, sub-Saharan Africa's largest country, the Allied Democratic Forces, a decades-old militant group, has traded claims of responsibility for deadly attacks with a local ISIS affiliate. The fighting compounds the deep hunger crisis there, with more than 19 million people in need, according to the International Rescue Committee, which reported that DRC now has "more people facing a severe hunger crisis... than has ever been recorded in any country."
In Mozambique, Islamist militants linked to ISIS have conducted brutal attacks in the northernmost province Cabo Delgado, including beheading more than 50 civilians in November and temporarily seizing control of a port in August. The deteriorating security situation has displaced more than half a million people, according to the U.N. refugee agency (UNHCR), with continued violence likely to bring more acute humanitarian need next year.
The situation is perhaps worst, however, in the Sahel, the semi-arid region that spans northern Africa just south of the Sahara Desert and that has seen a sharp rise in extremist groups and fighting. In Mali and Niger, the security situation is at best shaky, with a military junta trying to stabilize Mali amid inter-communal and jihadist violence and tense elections this week in Niger leaving the path ahead uncertain, but hopeful.
But Burkina Faso, the landlocked country twice the size of New York, has become the world's fastest growing crisis. Over 1 million people have been internally displaced in just two years, according to UNHCR, and there is no end in sight of fighting between the government, militia groups and terrorist organizations, boosting the risk of famine for its 20 million people.
Nigeria, the region's powerhouse and Africa's most populous country, is facing all the same trends, with even deeper implications for global security. Its northeastern corner has been a hotspot for over a decade, with jihadist group Boko Haram and criminal violence terrorizing and displacing millions of civilians. But Nigerian armed forces' response has been cast as failing, and the government also faced sharp criticism for its heavy crackdown on anti-police brutality protests -- signs that the state itself is increasingly unstable, which could create more chaos in 2021.
Peace efforts fail, crises worsen in Afghanistan, Yemen
Afghanistan and Yemen have been torn apart by conflict for years now, but 2021 could bring even deeper suffering for civilians in both countries.
In recent months, while Afghan government and Taliban delegations sit in luxury hotels in Doha, Qatar, for peace negotiations, there has been a spike in car bombings, rocket fire, targeted attacks on police and security forces, botched Afghan Air Force bombings, and assassinations of government officials, activists and journalists. Compounded by coronavirus, that has kept Afghanistan's already victimized civilian population in continued danger, even after decades of humanitarian need.
The peace negotiations were supposed to aim for a nationwide ceasefire as soon as possible, according to the U.S.-Taliban deal signed in February, but the militant group has resisted so far, using violence as leverage in talks. But if the violence is sustained into 2021, it could imperil negotiations and ignite into all-out conflict, just as U.S. troops draw down out of the country and the ISIS franchise claims more deadly attacks more frequently, according to Afghan officials and U.S. analysts.
Yemen has similarly faced years of stop-and-start peace efforts, but with coronavirus raging through the country with no health care system to track it, let alone treat it, the world's worst humanitarian crisis is expected to descend even deeper in 2021.
After five years of endless fighting, humanitarian funding is drying up, leaving approximately 80% of the population in need, according to aid groups. The U.N.-mediated effort has stalled, with the Saudi and Emirati-led coalition fighting in its own ranks as much as with the Iran-backed Houthi rebels, and neither side has shown real interest in protecting civilians, let alone peace talks.
One other near decade-old conflict to mention is Syria, where murderous strongman Bashar al Assad, backed by Russia and Iran, could test the incoming Biden administration by trying to finally seize control of the last pocket of rebels and jihadists in Idlib province, causing a bloodbath and pushing masses of packed Syrians fleeing into Turkey and beyond to Europe.
East Africa erupting as violence spills over borders
In the final few months of 2020, the greater Horn of Africa experienced a flash of violence, often spilling over borders and threatening to suck in the whole region in the coming months.
At the heart of it is Ethiopia, whose government went to war with well-armed political forces in its Tigray region, a conflict that continues to see sporadic fighting and claims of mass killings and that could worsen ahead of 2021 elections. It may also suck in neighboring Eritrea, long at war with Tigrayan leaders and now partnering with federal forces against them, leading to cross-border rocket fire and aerial bombardment.
Further endangering the region is the fact that the fighting sent tens of thousands of refugees scrambling into Sudan, itself on a rocky transitional road to democracy after decades of oppressive rule. The two neighbors are already locked in a dispute over the Grand Ethiopian Renaissance Dam, and occasional clashes along the border could enflame into another frontline.
Elsewhere in East Africa, Kenya and Somalia have cut diplomatic ties over Kenya's support for breakaway region Somaliland, heightening regional tension further. The move also means Kenya will likely pull its peacekeeping troops in Somalia, just as U.S. forces withdraw, leaving Somalia more vulnerable to al-Shabab, a powerful al-Qaida affiliate that will continue to plot attacks and increasingly conduct them abroad.
In the midst of it all, the fragile semi-peace in South Sudan, the world's youngest country still emerging from civil war, faces "catastrophic levels of hunger," according to the U.N.
"If left unchecked much longer, a strategic region could devolve into war -- with itself and others -- imperiling U.S. interests from the Red Sea to Europe," warned Cameron Hudson, a senior fellow at the Atlantic Council's Africa Center.
COVID-19, political crisis sink Venezuela even lower
Once one of Latin America's richest countries, Venezuela has been wracked by Nicholás Maduro's corruption and mismanagement, but the political opposition's efforts over the last two years have not forced him from power. Parliamentary elections in December were boycotted by the U.S.-backed "interim" leader Juan Guaidó and decried as fraudulent by most democracies, but they also pushed Guaidó and many on his team from the legislature -- leaving them with one less avenue of power.
That political stalemate has increasingly splintered the opposition, which could lead to more radical voices emerging -- sick of Maduro's intransigence and seeking alternative means. Instead of a political settlement, Venezuela is likely to see more social unrest, particularly as coronavirus further sinks Venezuela's economy and causes food and fuel shortages, with one quarter of the country's population in need, according to IRC.
But the danger could also become one for the region. Despite COVID shutting borders, Venezuelan refugees continue to escape the country, but their growing presence -- almost 2 million in Colombia and nearly 900,000 in Peru alone, according to the U.N. -- are starting to destabilize neighbors. This fall, Colombia has already seen protests and attacks on Venezuelans, who are blamed for rising crime or unemployment, which could escalate as COVID-19 further damages local economies.
Assertive China gets punched back
While the coronavirus emerged from Wuhan and threatened to overwhelm China, its draconian lockdown has allowed Beijing to emerge more quickly than other major powers -- rebooting its economy and taking advantage of the world's paralysis with increasingly assertive moves.
In Hong Kong, democratic protests have faded under COVID-19 restrictions, but particularly after China's national security law tightened its control on the territory. While protests could reemerge in 2021, the tale of the city now is of asylum seekers fleeing and activists incarcerated.
Elsewhere, China is likely to keep flexing its new muscles, asserting firmer control over now militarized islands in the South China Sea despite U.S. opposition and seeping its control across international boundaries, such as the disputed border with India's Ladakh region, continued claims against Japan's Senkaku Islands, and land grabs in Nepal and Bhutan, two tiny neighbors.
But these new moves could be met with clashes in 2021 as regional powers push back, often with increasingly vocal American support. India has banned Chinese apps and boosted its military spending and border troop presence, and Japan's defense minister said China had become a "security threat" -- both countries joining the U.S. and Australia under the Trump administration’s revitalized "Quad" format.
Nowhere is the tension fiercer than in Taiwan. Considered by Beijing a breakaway province that must eventually be reunited, Taiwan is likely to face more harassment from China's navy and air force after they upped their tempo this year. That was met by record-breaking arms sales to Taiwan by the Trump administration, totaling $18.3 billion over four years and including elite fighter jets and advanced torpedoes. With a Biden administration focused on issues at home, China could take the ultimate risk of forcing reunion by the barrel of a gun, which analysts fear but say remains unlikely.