Nic Robertson is CNN's international diplomatic editor. The opinions in this article belong to the author.

Munich's annual Security Conference felt tenser this weekend than it has in recent years.

The reason? The increasingly complex global security issues that world leaders are currently facing.

And in 2018, these threats and challenges feel increasingly connected: from sophisticated cyber attacks, to Syria and ISIS; from the EU's security and defense plans and Brexit, to North Korea; from Iran to Russia. The topics are familiar, but suddenly more pressing.

Unlike last year, when everyone awaited US Vice President Mike Pence's speech in the hope he'd calm concerns about President Trump's apparent pivot away from America's traditional allies like NATO, there was no such anticipation this year.

Yet Trump's influence -- or inconsistency thereof -- in the field of international diplomacy still echoed in the plush hallways and paneled rooms of the Bayerischer Hof hotel -- the security conference venue.

On Syria, former US Secretary of State John Kerry was asked about the absence of American political engagement. He said what is required is "real and artful diplomacy" -- a sentiment that will have struck a chord with UN Secretary General António Guterres, who told me of his concern about the sudden spike in violence.

But the tone of discourse this year did sound shriller than in the recent past.

Israel's Prime Minister Benjamin Netanyahu stole the show , rising above the cacophony of other voices with stark warnings of Iranian ballistic missile threats and an expansionist agenda: "Israel will not allow Iran's regime to put a noose of terror around our neck. We will act without hesitation to defend ourselves and we will act if necessary not just against Iran's proxies that are attacking us but against Iran itself."

Iran's foreign minister, Mohammad Javad Zarif, called Netanyahu's speech "a cartoonish circus" which "does not even deserve the dignity of a response."

He issued his own red lines for Trump over the Iranian nuclear deal, saying: "If Iran's interests are not secured, Iran will respond ... and I believe that it would be a response that people would be sorry for taking the erroneous actions they did."

Zarif -- who had come direct from a state visit to India to drum up business -- had missed Trump's National Security Advisor H.R. McMaster's speech the previous day, but was clearly taking aim both at it and at Trump, knowing that among Europeans -- and even with Kerry -- he would get some support.

McMaster said: "Now is the time to address serious flaws in the Iran deal and counter Iran's destabilizing activities." Saudi Arabia's foreign minister would echo these sentiments later.

A new alliance is taking shape. Although the criticism of Iran is not new, it is gaining rhetorical flourish and is less inhibited than it has been in recent history.

And the diplomatic gaps between major players are becoming increasingly apparent.

Guterres told me that one of his big concerns over Syria was that Israel's engagement in the conflict could trigger an escalation -- a view shared by many others.

He also told me that Russia's efforts to usurp the UN's Syria peace talks by shifting the venue from Geneva to Sochi earlier this year were nothing of the sort -- that the Sochi talks were a one-time development that fed the UN's Geneva process.

But Russian chairman of the state Duma on international affairs, Aleksey Pushkov, insisted that Sochi talks were an independent process and far from dead. This is a staggering gap between the UN chief and one of permanent five members of the UN Security Council.

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Pushkov wasn't the only Russian bringing a cooling effect to the proceedings. Both Russian Foreign Minister Sergei Lavrov and Moscow's former ambassador to the US Sergey Kislyak left a frosty nip in their wake.

Both were in denial -- particularly Lavrov, who is a regular at such meetings. His speech lacked his trademark confident verbal swagger. It was short, curt and defensive on all issues, extremely so on the indictment of 13 Russians accused of meddling in the US 2016 presidential elections, which he said was without evidence -- "just babble".

Kislyak was far more forensic in his counter claim: "I have in my briefcase a comparative table that was prepared on the basis of an analysis of computer security companies in a number of countries including in Russia and other countries. And is shows that the main source of computer threats in the world is not Russia - it the United States. Twenty to thirty percent."

McMaster pushed Russia further into their corner. "As you can see with the FBI indictment, the evidence is now really incontrovertible and available in the public domain. ... Now that this is in the arena of a law enforcement investigation it's going to be very apparent to everyone." He added, "I think Russia may re-evaluate what it's doing is because it's just not working."

If Russia is re-evaluating, it's certainly not doing so in public. But then not everything that happens at these conferences take place in public.

Netanyahu and his Mossad security team were in the Bayerischer Hof hotel a full two days before his speech, in an out of meetings with, among others, the UN Secretary General.

US Secretary of Defense James Mattis was there, but spent almost his entire time in closed door meetings -- as did many of the delegates from the other nations present.

If Netanyahu's public speech was any measure of his intent to persuade disbelievers, his private discussions can only be assumed to have been more blunt.

And while many were not surprised that Syria's spiral from proxy war to direct confrontation is bringing Iran and Israel to new degrees of enmity, the arrival of new cold fronts from closer to home in Europe are an unwelcome addition to the growing global disorder.

Germany's Foreign Minister said that he expected Russia and China to try to divide Europe with "sticks and carrots," but not Europe's allies -- a possible dig at Trump over his anti-EU rhetoric.

British Prime Minister Theresa May exposed another opening sore on the continent between the UK and the remaining 27 EU member states over security.

In her speech, she appealed for a new security partnership between the UK and the EU, offering concession on EU law and data protection.

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Such is the concern among intelligence chiefs that political bartering over Brexit will hurt vital cross-border security cooperation that UK's MI6 chief and his German and French counterparts were photographed for the first time ever together at a joint briefing during the security conference.

The combined overture seemed to get a cold shoulder from European Commission President Jean Claude Junker, who spoke immediately after May's announcement, saying: "I do not want to mix up security policy considerations with other considerations." Which of course has been May's stated aim all along.

However this particular Brexit issue is sliced, it cuts to the capabilities of Europe's politicians to deal with other issues on the agenda in Munich such as Syria, another topic very close to home for Europe.

NATO Secretary Jens Stoltenberg warned the gathered ministers of the perils of a consolidated EU defense policy -- something that is currently under consideration and seen by some as a rival to NATO.

Stoltenberg said 80% of Europe's defense costs are met by non-EU members: US, Canada, Turkey, Norway and soon to join them, the UK.

Mattis stressed during a bilateral meeting with his French counterpart that EU defense initiatives should not compete with NATO.

The longer the conference went on, the more big issues threaded themselves between different speeches and panels. The weekend took on the role of a mirror, showing the international security community exactly how serious things have got in the last year.

Significantly, Germany's defense minister criticized Trump from the podium for dialing back American diplomacy with budget and staff cuts at the State Department.

And the bad news kept coming. Microsoft's "fireside chat" about cyber threats and what to do about them turned out to be a glimpse into what is to come. Spoiler: worse, more sophisticated attacks.

Brad Smith, president and chief legal officer of Microsoft, said the world would need leadership to hold such attacks at bay. And in the context of the size and nature of this threat, that can only mean American leadership.

He described 2017 as the year of the cyber attack wake-up call.

On May 12, 2017, Smith said 200,000 computers were impacted by an attack -- near simultaneously -- in 150 countries.

Never before in the history of conventional conflict has an attacker be able to strike so many, over such a dispersed area, in such a short space of time.

In a video montage featuring real hospital patients who missed surgeries as a result, he told the human impact of the attack and warned that while this cyber attack didn't kill anyone directly, the next one might.

He went on to talk about the risk of "cyber weapons" and a new "great challenge" to "partner with tech giants to stop the threat."

After sitting at Smith's hearth for an hour, stepping into the sub-zero Munich night brought yet more chilling clarity.

A world without an engaged or focused superpower is a scary place.

Dangerous situations become more volatile and the voices around them become increasingly voluble.