Last year was one wild, unpredictable and unforgettable ride, but 2017 could well be as frighteningly full of shocks, with everything from global trade wars to a new nuclear arms race potentially on the horizon.

Those who vividly remember the Cold War find it surreal to hear Moscow and Washington talking almost eagerly of nuclear arms buildups after two decades of historic co-operation on arms control.

Russian President Vladimir Putin spoke in December of Russia's need to upgrade its nuclear weapons arsenal and U.S. president-elect Donald Trump reacted by telling a morning show: "Let it be an arms race … we will outmatch them at every pass."

U.S. President-elect Donald Trump's relationship with Russian President Vladimir Putin has become confusing. On one hand, they seem intent on developing closer relations between their countries. On the other, they seem ready for a new nuclear arms race. (Jonathan Ernst/Reuters)

It's not quite clear how intense an arms race will develop if Putin and Trump forge better relations, but the dangers of 14,000 warheads held by Russia and the U.S. are still incalculably vast.

Not just because they can reduce civilizations to instant rubble in war, but because even in peace, command systems are subject to false alarms and accidental use and increasingly vulnerable to cyberattacks. Yet in stark contrast to during the Cold War, there's scarcely any public debate about the weapons these days, says Eric Schlosser, a leading author on nuclear control.

"My greatest concern is the lack of public awareness about this existential threat," he wrote in the New Yorker as the year ended. "These machines have been carefully designed to kill us. Complacency increases the odds that someday they will."

The Pacific's other nuclear threats

But a new U.S.-Russia arms race is by no means the only nuclear concern. North Korea has been busy testing its nuclear creations as it tries to perfect ballistic missiles capable of carrying warheads to Japan and even North America's West Coast.

The Pacific's other nuclear power, China, appears to have seriously deteriorating relations with the U.S. since Trump, upon his victory, accepted a call from the leader of Taiwan and then tweeted about it. China was outraged because it considers Taiwan an integral part of its homeland and not an independent country — a position the U.S. has publicly respected for decades with its "one-China policy."

Interesting how the U.S. sells Taiwan billions of dollars of military equipment but I should not accept a congratulatory call. —@realDonaldTrump

China also has worrisome territorial disputes with Japan, Vietnam and other Asian nations.

In late December, China conducted both a sea and air exercise close to Taiwan's territory, prompting the island's defence minister to declare: "The threat of our enemies is growing day by day."

It was around this time, Japan announced major increases in defence spending, including anti-missile defences to guard against the nuclear strength of both North Korea and China.

The potential impact of Trump's stated animosity to China as a trade and currency manipulator, combined with the suspicion rife in Beijing that Trump won't respect the one-China policy so vital to Pacific stability and the global economy, is yet another unknown to jangle nerves.

The reality is nobody in any part of the world can confidently predict how Trump will guide the U.S.

It remains to be seen whether Trump's boardroom negotiating tactics will work in his new job. (Mike Segar/Reuters)

His enthusiasts applaud the fact he's "transactional" as opposed to ideological and will always look for a deal favourable to U.S. interests. But his gift for bargaining is untested in an international crisis.

This is a president-elect with no government experience who calls for a boost to the U.S. nuclear arsenal before he's even taken the oath of office and whose preferred method of diplomacy seems to be writing snap judgments using 140 characters or less on Twitter.

Yes, 2017 promises to be particularly turbulent — and the Trump factor looms large just about everywhere.

Populism in Europe

Already shaken by the U.K.'s Brexit vote in June, Europe is seeing the remarkable rise of populist movements that are furious at the status quo. The months ahead will see a string of national elections: the Netherlands in March, France in May, Germany in October and Italy at some point as well. In each contest, opposition parties will test the very notion of a united Europe.

The continent's most powerful leader, Germany's Angela Merkel, is likely to win her electoral battle, but to try to make sure of it she's been tacking her Christian Democratic Union party sharply to the right, including with her recent support of a proposed burka ban.

German Chancellor Angela Merkel faces populist anger in her re-election bid, particularly because of her open-arms policy for refugees. (Hannibal Hanschke/Reuters)

The politics of Europe will continue to be tested by the migrant and refugee crisis, which polls have shown is a major source of populist anger. More than 347,000 newcomers arrived last year, a million the year before, and thousands have died at sea. And yet there's still no solution in sight.

Fear that anti-EU sentiment could start to fragment Europe is a major concern for NATO. Especially with a new U.S. administration on the way that's been very critical of "freeloaders" inside the alliance and that might drop sanctions against Moscow in favour of working ties. It's not even clear yet how strongly Trump will support NATO's eastern members along or near the Russian border.

Boiling hatreds in the Middle East

Conflicts in Syria, Iraq and Yemen will test Trump's oft-stated desire for a reduced American role in the Middle East.

In Syria, he'll have his chance to use his cozy relationship with Putin to discuss a possible safe haven for refugees as well as a U.S./Russian offensive against ISIS.

An internally displaced Syrian boy walks through mud in the Bab Al-Salam refugee camp, near the Syrian-Turkish border in northern Aleppo province. (Khalil Ashawi/Reuters)

But boiling religious hatreds in Syria and Iraq threaten to spill over.

Sunni Muslims are incensed about the lack of support from the West during the bombing and shelling siege of Aleppo, Syria, that killed so many followers. The brutal assault was conducted largely by Iranian-backed Shia fighters and Russians, seen by many in the Middle East as the champion of the Christian minority — a calculation that could fan more attacks on the dwindling number of Christian communities in the region.

Lasting problems in South Asia

In South Asia, Afghanistan is likely to demand reinforcements from Trump as the Taliban continues to gather strength in its latest offensive.

And the unsteady relationship between the region's two nuclear powers, India and Pakistan, remains potentially the most dangerous flashpoint on Earth.

An Afghan man removes burnt items from the Kabul house of an Afghan member of parliament after the home was attacked by the Taliban on Dec. 22. (Omar Sobhani/Reuters)

There are too many potential conflicts in the world to list here, possibly more than during the Cold War when superpowers often slapped lids on dangerous flare-ups. What's also striking is how quickly and confusingly these crises move.

"No single problem compares with the Cold War at its height, but the sheer number and complexities of the difficult issues are without precedent in modern times," writes Richard Haass, longtime diplomat and head of the Council on Foreign Relations in New York.

This vortex of crises means we'll need extraordinarily competent world leaders to avoid dangerous geopolitical and economic upheavals over the next few years.

That's a great deal to hope for in a hurry.